View Full Version : Conversion from trailer-sailer to low power motor boat


Dr. Peter
04-27-2010, 03:22 AM
I have a Hartley 18. It was a sail boat. Now it is a low-powered (8hp) displacement camp cruiser.

To bring about this transformation the mast, mast step and associated paraphanalia was removed.

The centre-board casing was removed along with the steel centre-plate. The slot plugged with a board and back-filled with West System (no leaks). The resulting space inside the cabin is fabulous.

I also removed the porcelain toilet which pumped straight out of the boat (illegal where I live) and extended the quarter-berth. You can actually rollover without having to think very much about it.

The centre-plate was then cut up and retained as ballast along with other heavy material to equal the weight of the mast. I can't quite bring myself to attack the rudder (also steel plate) in quite the same way. The ballast sank the boat further into the water so that fore and aft trim is better under high power.

I purchased a fixed height outboard motor mount and fitted the same in the centre of the transom. To the leg of the outboard (it was extra long) a friend and I fashioned a rudder for better low-speed control.

The boat is used in rivers and sheltered bays - at hull speed. The 8hp Yamaha 2-stroke (dual thrust) manages things quite well in calm situations, as long as the current isn't too strong, and as long as you are going along at about half hull speed. But its not a relaxing engine to listen to when you ask it for a bit more.

I have enjoyed the boat in this version for a couple of years now.

The next phase of the conversion after this is to fit the motor directly to the transom and increase the hp. Hartley recommend 5-30hp for the Hartley Fisherman, a motor boat heavily influenced by the Hartley 18 design.

1. Can the forum recommend a small modern tiller-controlled outboard?
2. Can the forum advise me on how I might reinforce the transom?

The cockpit now has an after-market bimini which is OK for sun protection but I doubt it will be any use in heavy rain.

3. Can the forum point me towards ideas they have seen or constructed themselves where shelters, dodgers etc have been retro-fitted?
4. What materials were used?

In the photo (attached I hope) you can see the short mast. At one point a steadying jib sail was part of the mix but not any more.

Regards one and all,

Peter

waikikin
04-27-2010, 03:48 AM
Hi Peter, definatly go for a four stroke outboard, heaps easier to live with so far as noise goes, I've had Yamaha 9.9 four stroke & it was a very good engine, I beleive they may have changed a bit, but would still be fine for your boat. All the best from Jeff.

Dr. Peter
04-27-2010, 04:12 AM
Hi Jeff,
I have had mixed commentary about the Yamaha 9.9 hp 4 stroke. Some very positive some ver negative. I have had some expose to small Hondas 10 and 15 hp. Four blade props. Very impressive.

The weight issue gets me. Like a 10 hp 4 stroke is pretty heavy and for about the same weight I could get maybe 5 more hp in a two-stroke which would then push my boat along a lot easier.

The Yamaha 8 I currently use runs at 100:1 petrol:oil mix and smoke is pretty much a non-issue.

Another random thought is what about two small four-strokes on brackets. Then I could re-mount my rudder????

Thanks for the feedback

Peter

Easy Rider
04-27-2010, 11:58 AM
Dr Peter,
I really like your boat ..AND the way you are using it. I have an 8hp Yamaha that I use on a really large canoe. I only use 3-5hp and it's very quiet and smooth. But if you want to make waves w your Hartley and be as whisper quiet as possible get a 20hp Honda and run it at half throttle (or a bit less) and if thats not quiet enough throw a heavy coat over the engine. If you want to save some money find a 15hp (white) Johnson. It's actually a Suzuki. A friend of mine has a little fleet of them he rents to fishermen and has found them to be excellent. I have considered turning a larger sailboat into a trawler but that presents some significant problems.
Your application looks excellent.

Easy Rider

Stumble
04-27-2010, 12:07 PM
Peter,

1) I don't know about australia law, but in the US there are very different registration requirements when a boat has anything larger than a 10hp engine on it, which is why pretty much all manufacturers make a 9.9hp engine. It may be completely irrelavent for you but I would check.

2) I have doubts that increasing the Hp would do anything but cause you to burn more fuel. I don't think the Hartley 18 was designed to be able to plane, so once you hit hull speed you can add all the power you want but won't go any faster.

3) 4 strokes are MUCH quieter than 2 strokes, but come at the cost of extra weight and torque. Which is why most lifting outboard brackets that allow the use of 4-strokes are significantly larger than their 2 stroke counterparts ( one I looked at recently was rated for 7hp if a 4 stroke, and 25hp for a 2 stroke)

I really like what you have done with the boat by the way! The idea of cruising under power efficiently is always a cool proposition to me.

messabout
04-27-2010, 12:53 PM
A while back, the devil made me buy a derelict Thistle for $75. No mast, centerboard, or rudder. I have sailed Thistles competitvely but that was not the aim. It was converted into a beach cruiser. I bought a new Johnson electric start 9.9 two stroke. I ignored the four stroke counterpart because I thought it too heavy. I knew, going in, that the 9.9 was overkill but the dealer made me an attractive offer. Turns out that the too big motor was perfect. The thing was/is whisper quiet when running at 5 knots of boat speed. In addition it sips fuel at the rate of about 12 miles per gallon. It does not vibrate or intrude on tranquility in any way. And it is not smokey. The motor has the capacity to plane a boat of this size if only it was a planing hull. The Thistle will plane under sail but in order to get it up with the engine, the boat must be heavily bow loaded. I only tried that a couple of times just to see if I could make the boat plane. Yes, but not worth the hassle, noise, rough ride, and all that jazz. The boat will run at about 6.5 knots before the wake becomes mountainous and the motor begins to do a litle work.

One of the gratifying features of this boat is that it can outrun Donzis, Rivas, and other really fast boats. This is not a complete lie. When in a no wake zone, we just move right along with no muss or fuss, and only a tiny ripple of wake. while the super boats must merely creep in order to prevent the gosh awful wake that characterizes them.

The Johnson or Evinrude of 97 vintage would make a very acceptable motor for the boat that you have. I suspect that there are newer models of two stroke that would be equally satisfactory and quiet.

Dr. Peter
04-27-2010, 07:52 PM
Hi Peter, definatly go for a four stroke outboard, heaps easier to live with so far as noise goes, I've had Yamaha 9.9 four stroke & it was a very good engine, I beleive they may have changed a bit, but would still be fine for your boat. All the best from Jeff.

Jeff,
I think the 9.9hp 4 stroke Yamaha can also be fitted with a large prop. Is that right? I wonder how that changes performance?
Peter

Dr. Peter
04-27-2010, 08:04 PM
Dr Peter,
I really like your boat ..AND the way you are using it..... If you want to save some money find a 15hp (white) Johnson. It's actually a Suzuki. A friend of mine has a little fleet of them he rents to fishermen and has found them to be excellent..... Your application looks excellent.

Easy Rider

Thanks for the kind words.
The Hartley in its current form gets around all that rigging and de-rigging before and after a cruise.

Are far as sailing goes I race a catamaran around the cans each weekend and crew for friends with large sailboats occasionally. They always need crew.

If I hadn't made the change my Hartley would have been redundent.

Is the Johnson a 2 or 4 stroke?

Peter

Dr. Peter
04-27-2010, 08:11 PM
Peter,

1) I don't know about australia law, but in the US there are very different registration requirements when a boat has anything larger than a 10hp engine on it, which is why pretty much all manufacturers make a 9.9hp engine. It may be completely irrelavent for you but I would check.

2) I have doubts that increasing the Hp would do anything but cause you to burn more fuel. I don't think the Hartley 18 was designed to be able to plane, so once you hit hull speed you can add all the power you want but won't go any faster.

3) 4 strokes are MUCH quieter than 2 strokes, but come at the cost of extra weight and torque. Which is why most lifting outboard brackets that allow the use of 4-strokes are significantly larger than their 2 stroke counterparts ( one I looked at recently was rated for 7hp if a 4 stroke, and 25hp for a 2 stroke)

I really like what you have done with the boat by the way! The idea of cruising under power efficiently is always a cool proposition to me.

1. I don't think the 10hp limit applies here. Any boat with a motor has to be registered.

2. I do appreciate the hull-speed limitation. My boat is ballasted too. The extra power is about pushing more easily and quietly against the current in a river and the weather in a bay.

When it was a sailboat it did plane on one occasion. It was a screaming reach in about 25 knots - there were three of us on board - and it was exhilerating.

3. Thanks for the tip about the outboard bracket. I bought mine from the US over the internet. It is marked 5-15hp. I always thought this was about power. I never considered the weight issue. I have reinforced its carrying capacity but I think mounting the motor to the transom is the way to go.

Peter

Dr. Peter
04-27-2010, 08:17 PM
A while back, the devil made me buy a derelict Thistle for $75. No mast, centerboard, or rudder. I have sailed Thistles competitvely but that was not the aim. It was converted into a beach cruiser. I bought a new Johnson electric start 9.9 two stroke. I ignored the four stroke counterpart because I thought it too heavy. I knew, going in, that the 9.9 was overkill but the dealer made me an attractive offer. Turns out that the too big motor was perfect. The thing was/is whisper quiet when running at 5 knots of boat speed. In addition it sips fuel at the rate of about 12 miles per gallon. It does not vibrate or intrude on tranquility in any way. And it is not smokey. The motor has the capacity to plane a boat of this size if only it was a planing hull. The Thistle will plane under sail but in order to get it up with the engine, the boat must be heavily bow loaded. I only tried that a couple of times just to see if I could make the boat plane. Yes, but not worth the hassle, noise, rough ride, and all that jazz. The boat will run at about 6.5 knots before the wake becomes mountainous and the motor begins to do a litle work.

One of the gratifying features of this boat is that it can outrun Donzis, Rivas, and other really fast boats. This is not a complete lie. When in a no wake zone, we just move right along with no muss or fuss, and only a tiny ripple of wake. while the super boats must merely creep in order to prevent the gosh awful wake that characterizes them.

The Johnson or Evinrude of 97 vintage would make a very acceptable motor for the boat that you have. I suspect that there are newer models of two stroke that would be equally satisfactory and quiet.

My 8 hp 2 stroke Yamaha is just a couple of years old. It was sold as a Yacht motor. Its great. It starts very earily and there are no fumes. I particularly like the dual thrust - it saves crashing into docks.

The rudder attachment works very well at slow speed because it allows easier steering. I don't have to use power to thrust the rear of the boat around.

Its just the noise issue which isn't terrible unless you are pushing close to hull speed. Are covers any use do you think?

Peter

Peter

Dr. Peter
04-27-2010, 08:39 PM
The cockpit now has an after-market bimini which is OK for sun protection but I doubt it will be any use in heavy rain.

3. Can the forum point me towards ideas they have seen or constructed themselves where shelters, dodgers etc have been retro-fitted?
4. What materials were used?

Peter

I have had a lot of feedback about the motor which is great.

I have attached another image. This time we are anchored off a beach with mooring lines to the shore. Stuff that was in the cabin is now in the cockpit and a lightweight mesh to stop the insects is thrown over the bimini and clipped to the sides of the boat.

The second part of my question for the forum was around sheltering the cockpit. Any ideas here please, forum?
Peter

Dr. Peter
09-05-2010, 10:32 PM
After using the rudder-motor combination I have since refitted the original tiller and rudder and off-set the outboard back in its original position to the starboard side of the transom. The set-up is more sensitive and I can steer standing up.

Peter

troy2000
09-05-2010, 10:50 PM
Thanks for bumping the thread; I missed it first time around. It makes me think about looking for something I can use as an overnight and weekend motor-sailor, until I get around to building the sailboat I want.

Have you had any ideas yet about replacing the bimini?

PAR
09-06-2010, 12:14 AM
You can't over power this particular hull form. Though it does share some similarities with it's powerboat brothers, the "run" is quite different and you're best suited with a 10 HP engine or less. With 10 HP you can expect quite impressive preformance, particularly if you get her trimmed out just right.

Remote steering, throttle and shift controls aren't terribly difficult to engineer or that costly, especially if second hand. With the remote helm, you could move forward in the cockpit and have some protection behind the cabin bulkhead. This would be the typical arrangement of a power cruiser.

A cockpit cover could be one of several ideas. A bimini is the logical choice, like you have shown. It can be retracted and more importantly it can be modified easily. The usual modification is to make it's forward portion a "dodger", which would keep mother nature out of the companionway hatch, unless you wanted her.

FAST FRED
09-06-2010, 08:02 AM
"The extra power is about pushing more easily and quietly against the current in a river and the weather in a bay. "

A 5K boat goes thru the water at 5K, extra power gets you nothing, in a 5K current you might as well anchor as add power .

Wind is different so my suggestion would be to find an outboard with a deep reduction gear that can spin the biggest diameter propeller .

These will be created to push sailboats , not small open boats , so they should be available , perhaps used..

You might also find sail boat pushers have somewhat larger alternators , so you can charge the house batteries when underway.

FF

SamSam
09-06-2010, 10:03 AM
I had a 22' O'Day and enjoyed it a lot while the mast was out and just motoring it around.

At the moment there is a 26' sailboat down at the marina that could be had for nothing. It has a weighted fixed keel, maybe 3-4' deep. If that was cut off, the mast and all removed, would that hull be stable for motoring around?

PAR
09-06-2010, 10:27 AM
Fred has a good point, purchase a high torque outboard. Sam, your 26' prospect need to have it's ballast kept in place (or replaced with a similar weight) or she'll float too high and be very "tippy".

philSweet
09-06-2010, 12:27 PM
I converted a 16' sailboat to a motor skiff when I sold it to my girlfriend. Originally planned on a short shaft, hence the large well. I realized at the last moment that the tiller would be uncomfortably low; so I switched to a long shaft and added a riser which is also wedged to about 1 in 10. An important factor when selecting your outboard is its charging system. Being able to get 6-10 amps charging may encourage you to oversize a bit. The cutout off to the side is where the old 2hp used to go.

Dr. Peter
11-12-2010, 07:46 PM
Thanks for bumping the thread; I missed it first time around. It makes me think about looking for something I can use as an overnight and weekend motor-sailor, until I get around to building the sailboat I want.

Have you had any ideas yet about replacing the bimini?

It's been awhile since this question was posted - sorry for the tardy reply. I have kept the bimini - it was a generic 3-bow style. I have now moved it from inside the cockpit where it tended to interfere with comfortable lounging and mounted it onto the cabin roof. I shortened the length of the legs quite considerably.

It now shades the hatchway and the front half of the cockpit. Being further forward means I can steer standing up which I like to do. Having re-installed the tiller and rudder means I can sit further forward and get some shade when required.

I still need to fold the bimini away for travel.

Peter

PAR
11-13-2010, 02:57 AM
That would now be called a "dodger" Peter.

Dr. Peter
11-13-2010, 05:55 AM
There is no screen. yet!

Dr. Peter
12-02-2010, 07:26 PM
"The extra power is about pushing more easily and quietly against the current in a river and the weather in a bay. "

A 5K boat goes thru the water at 5K, extra power gets you nothing, in a 5K current you might as well anchor as add power .

Wind is different
FF

I remember one time being in a 7.7m trailer sailer and the wind was kicking up to 30 knots and the waves were becoming an issue. We decided to go for the motor (a Hp 4 stroke Honda) and all it would do was hold the boat in place. We needed some sail up plus the motor to get going again. The motor seemed mainly ensure the waves did not stop us too much.

Would 15hp instead of 10 made a difference under this scenario do you think?

PAR
12-03-2010, 12:38 AM
The sailing rig and furled sails can offer a lot of windage on a sailboat, which wouldn't be the case with your new conversion. A 15 Hp, particularly a high output wouldn't be a bad choice, though you'd be running it at 1/2 throttle all the time and fuel efficiency will drop as a result. On the other hand, you'd have a healthy reserve for those relatively rare occasions you need to really punch through a mess to get home.

cathyoz
12-04-2010, 01:31 PM
1. I don't think the 10hp limit applies here. Any boat with a motor has to be registered.

Peter

just little point
no 10 hp , do not apply
but only boat with a motor over 3 kw ( 4 hp ) need to be registered

cathyoz
12-04-2010, 01:39 PM
I had a 22' O'Day and enjoyed it a lot while the mast was out and just motoring it around.

At the moment there is a 26' sailboat down at the marina that could be had for nothing. It has a weighted fixed keel, maybe 3-4' deep. If that was cut off, the mast and all removed, would that hull be stable for motoring around?

i have a 25 fts in my garden
i was thinking to cut the keel and just put a out rigger ( prao style), to just used it as motor camping home in the river.
i will put some removable lead if necessary, and water ballast in the bilge , so she will be lighter when traile or move around

Fanie
12-04-2010, 01:57 PM
Re your cockpit cover.

You get these fiberglass tent ribs that you bend and it forms the tent. You could think along the lines of something like that. If you have two in parallel left to right bent in a bow and with a support in the center from the front to the rear one you can adjust the height of the material from open to closed left and right.

On the front part you can put some see through... plastic for protection against rain. Many tents have these see through 'windows'.


On the motors - the old 2 strokes were smokers (like me), but the new two strokes are a cut above what they used to be. They have quite a bit more torque than the 4 stroke (sorry Jeff), they don't smoke, they comply to required emissions and they run softer too and weigh a lot less. All in all, I'll choose the 2 stroke every time since two strokes almost have no end either. There are the Parson motors and the Toyatsu's I know of and priced not too bad either. I'll take the Toyatsu if it was me.

FAST FRED
12-05-2010, 08:52 AM
"Would 15hp instead of 10 made a difference under this scenario do you think?"

Probably not in the least , you need to plane to get to windward in a current faster than the boats hull speed.

Maybe a 50 hp ?

FF

cathyoz
12-05-2010, 02:26 PM
15 hp is much eavier than a 10 hp even the 8 hp long sharft
used more fuel , and not always faster as the hull has a maximum speed design , if you go too fast , all the structure of the boat will colapse.

Dr. Peter
12-11-2010, 07:39 AM
Has anyone come up with a decent tiller extension for an outboard motor? I have tried a commercial clamp design but it just isn't strong enough.
Peter

Dr. Peter
12-11-2010, 07:40 AM
I have decided to stick with the 8hp 2stroke dual thrust Yamaha.
Peter

Dr. Peter
12-11-2010, 07:44 AM
OK forum - opinions please. My Hartley 18 does not have a forward hatch. It would make the boat more comfortable to work and sleep in if it did. How should I go about sourcing and fitting one. I am also a bit interested in retrofitting a slot-top like the AF4 - would this be a step too far?
Peter

PAR
12-11-2010, 09:10 AM
The slot top would compromise much of the deck and cabin strength. I wouldn't recommend it.

A forward hatch is a simple thing to make and doesn't require a lot of difficult joinery. On the other hand you can buy one (bring a big purse, they ain't cheap) and follow the instructions inside. On a boat that size, I'd use 1x2's for the edges and a piece of plywood bent over it, for the top. You could install a prism for light below if desired.

Dr. Peter
12-27-2010, 05:46 AM
Apologies for not responding sooner - I think a home-made hatch would be a better option. The Hartley has two quite simple hatches at the back of the cockpit - they are basically a wooden lid held down with an ocky strap. It would be fairly simple to emulate these.
Peter

Dr. Peter
12-31-2010, 06:21 AM
After using the rudder-motor combination I have since refitted the original tiller and rudder and off-set the outboard back in its original position to the starboard side of the transom. The set-up is more sensitive and I can steer standing up.

Peter

The tiller is gone again and I am back to a centrally-placed outboard. It works better this way on the river. The big rudder was better in the bay.

tinkz
01-07-2011, 06:27 PM
as af4 gets mentioned yet again.. lol I wanna build one!

I do like your camper, and have though about converting a small fiberglass cabin sailboat for power (if I find one for near nothing thats appropriate to start with), grafting foam, luan, and fiberglass to change the hulls shape for slow planing, but honestly, I could probably just go ahead and build a new af4 cheep enough.
what you have for power now, would probably just shove it (af4) up onto a slow plane.

Dr. Peter
01-08-2011, 05:23 AM
This was a trailer sailer once, Tinkz

http://yachthub.com/list/boats-for-sale/used/trailer-boats/custom-trailerable-cruiser/65505

Beautiful job.

Peter

Dr. Peter
09-20-2011, 08:00 AM
Its happened - after nine months of ruminating and the boat sitting there unused because it did not properly fit the purpose. I bought a circular saw and cut the slot top.

I then had to build up and extend the runners for the hatch to return some lost strength. Not too hard - I love West System. I would not want to stand on it but it serves, especially on a river where we get up on the boat rather stepping down on it.

I have chopped the ends from the old mast to use as a beam to support a tarp and insect mesh for camping under.

The boat does not even look that strange. How unusual is a sailboat with the mast carried horizontally?

Still working on it. But happy times in the shed.

What got me going was some U Tube footage on the AF4 and Skiff America. My boat does not perform like these but the idea is similar. Credit to them.

Peter

Dr. Peter
12-09-2011, 05:33 AM
Is this what I have - a terminal trawler?
Nudge
Has any one else done this?
Peter

peabody
08-21-2012, 01:32 PM
i have a sail boat ...(yes!) ... picking it up this weekend..
till the day i learn to sail..im going to just motor cruise around ..it has two sleeper berths.
thinking it be alotta fun camping out. .. i do have a standard yammie 9.9 long shaft...might trade it in for a high thrust model.

looking forward to this.
peabody

Dr. Peter
08-21-2012, 11:42 PM
Check out the art of motorsailing on the main. The ride will probably be more comfortable.

PAR
08-22-2012, 06:24 PM
Just hoist the sail and go for it. The art of sailing isn't especially hard, though doing it well is as challenging as any other sport.

Better yet would be to take out a buddy that actually can sail and have them show you the way things work. You'll learn much faster and you'll be propelling your boat as it was meant to be, not to mention for free, by mother nature.

peabody
08-23-2012, 04:14 PM
thanks guys... trouble is i know nobody who knowshow to sail.
zero .
im in central missouri . asked all friends and family. non of us know a thing .
let alone knowing anyone who sails...lol
but i think i can figure it out.
but see ? that's why im asking about the use of my yammie 9.9... a small motor cruiser till i know how to use a sail.
i was under the impression the yamaha high thrust would be a better motor for a sail boat.
but anyhow . thanks.
peabody

PAR
08-23-2012, 11:31 PM
The 9.9 on your boat is more motor then you need. A high thrust version wouldn't make you go any faster, but would be able to shove more weight.

Put an ad in the paper or on line for someone to show you how to sail. You can muddle through. but it's a lot easier (and safer) having some basics in hand as you learn. I've preformed this task countless times and after an hour, they're on their own and better for it.

OLDBRAVE1
08-29-2012, 11:28 AM
I have two older Highlanders. Only need to sail one and was thinking about converting other to beach/bay cruiser. Thought about removing centerboard box and center board and adding a strongback? down the hulls center similar to a pennYan hull. I would mount the outboard on rear and possibly add some hard chines on upper hull sections. Wanted to keep the deck the same but put in a slightly elevated floor with additional foam floatation. rearrange the seating to across the hull. I would mount a gas tank in front..20 gal.and place hose under flooring. What are your thoughts. Saw one like this on Cape Cod and it seemed most roomy, dry, and easy in and out of back waters.A while back, the devil made me buy a derelict Thistle for $75. No mast, centerboard, or rudder. I have sailed Thistles competitvely but that was not the aim. It was converted into a beach cruiser. I bought a new Johnson electric start 9.9 two stroke. I ignored the four stroke counterpart because I thought it too heavy. I knew, going in, that the 9.9 was overkill but the dealer made me an attractive offer. Turns out that the too big motor was perfect. The thing was/is whisper quiet when running at 5 knots of boat speed. In addition it sips fuel at the rate of about 12 miles per gallon. It does not vibrate or intrude on tranquility in any way. And it is not smokey. The motor has the capacity to plane a boat of this size if only it was a planing hull. The Thistle will plane under sail but in order to get it up with the engine, the boat must be heavily bow loaded. I only tried that a couple of times just to see if I could make the boat plane. Yes, but not worth the hassle, noise, rough ride, and all that jazz. The boat will run at about 6.5 knots before the wake becomes mountainous and the motor begins to do a litle work.

One of the gratifying features of this boat is that it can outrun Donzis, Rivas, and other really fast boats. This is not a complete lie. When in a no wake zone, we just move right along with no muss or fuss, and only a tiny ripple of wake. while the super boats must merely creep in order to prevent the gosh awful wake that characterizes them.

The Johnson or Evinrude of 97 vintage would make a very acceptable motor for the boat that you have. I suspect that there are newer models of two stroke that would be equally satisfactory and quiet.

SamSam
08-29-2012, 07:35 PM
I have two older Highlanders. Only need to sail one and was thinking about converting other to beach/bay cruiser. Thought about removing centerboard box and center board and adding a strongback? down the hulls center similar to a pennYan hull. I would mount the outboard on rear and possibly add some hard chines on upper hull sections. Wanted to keep the deck the same but put in a slightly elevated floor with additional foam floatation. rearrange the seating to across the hull. I would mount a gas tank in front..20 gal.and place hose under flooring. What are your thoughts. Saw one like this on Cape Cod and it seemed most roomy, dry, and easy in and out of back waters.
A proper steering wheel and throttle up front makes motoring much better. It gets you away from the motor and eliminates the awkward body position of tiller steering. That looks like a good boat for conversion.

PAR
08-30-2012, 01:40 AM
. . . A proper steering wheel and throttle up front makes motoring much better . . .


Not to mention gets you out of the boat's butt, making trim issues easier to address.

larry sellers
10-30-2012, 07:02 PM
I've been saving a 2 cylinder wisconsin gasoline/kerosene engine (about 18 hp) to plant in a sound sailboat hull as an inboard - making a funky sort of pilot-house "cruiser" - something about 21 feet. Of course old hulls are more or less free. Yes, sailboats can be pretty stiff without their rigging, but many of the day-sailer hulls look suitable to me, and might even plane in a flat out emergency full-power mode. I expect to have to do some stability calculations and 'sperimentin'....and add some steel bedded in seak-a-flex to protect the shaft/prop. Had anybody seen any examples - I'd like to crib from their good ideas and avoid their mistakes...

larry sellers
11-21-2012, 03:24 PM
I've been reading up on this subject for quite a while. Some thoughts - Everyone knows that work/fishing boats called "trawler" or dragger or dogger or smack - all these types, began as sail designs of modest size. They were converted to steam and motor power (and began to grow!) at the close of the 19th century, although conversion of fish boats from outboard/sail to inboard petter type diesels continues today in the third world fishing fleets of small boats. In trawlers, the low speed sail type hull remains in modified form - recognizable at least as a descendant of sail. Converting an old mac or venture hull or whatever to a "terminal trawler" is more practical now than it was in 1912 - 100 years ago. What you get is slow and cheap to run. Yes, the boats tend to be uncomfortable with respect to ride, but a careful attention to (and competent calculation of) stability and roll-damping (proper ballasting and bilge keels), and keeping a bit of sail, can result in a low-cost and fun boat. Direct drive inboard engines are around and the diesels (listeroid and petter types with compression release) can (check the oil pump design!) be spun in reverse with prestolite electric reversible motors - giving approximately the functionality of a direct-reversing engine, sort of (at least long enough to maneuver out of a slip). No quick reversing, though, takes a while to stop and reverse such engines even if there's a flywheel brake. Sure, a transmission is better. But not essential. It's my intent to build something along these lines with a center pilothouse and a 650 rpm diesel engine. Collecting the stuff... The Lister makes 6 hp@ 650 revs and uses about 1 gallon per 4 hours. Don't use it much anymore and planning to pull it out of my generator shack when we move.) I remember seeing working small trawlers as a child - and it makes me want to build my own. Go figure!

muskymania
11-26-2012, 08:37 AM
I know you said you wanted to go up a bit in hp, but I thought I would just throw out the idea of a propane outboard. I've heard sailors love them because there are hardly any emissions and they are virtually matinance free. I've seen a 5hp I'm not sure if they make any larger ones.

larry sellers
11-27-2012, 10:30 AM
i have seen diesel outboards, and kerosene, but propane is something new to me. I believe I'd be concerned about fire dangers and fuel consumption - lp, being introduced as a gas displaces air and has the effect of lowering both compression ratio and power output. being a heaver-than-air gas at stp it seems like a problematic fuel for a decked-over boat.

muskymania
11-27-2012, 05:05 PM
i have seen diesel outboards, and kerosene, but propane is something new to me. I believe I'd be concerned about fire dangers and fuel consumption - lp, being introduced as a gas displaces air and has the effect of lowering both compression ratio and power output. being a heaver-than-air gas at stp it seems like a problematic fuel for a decked-over boat.

I haven't seen the propane outboard in action but I heard you can run it 10 hours on a 20lb tank of propane which is actually pretty cheap.

larry sellers
11-27-2012, 05:46 PM
Well, let's see...20# of LP is about 4.7 gallons, and over ten hours that's an average consumption of 0.47 gallons or just under 2 lbs per hour. Colorado State (http://www.ext.colostate.edu/pubs/farmmgt/05006.html) says 0.080 gallons of LP gives (in the real world of farm and dirt) one horsepower for one hour. Let's assume a "5 HP" 4 stroke motor (I guess it could be done with a 2 stroke, but it'd be tough) so, 5 x .08 = 0.4 (gallons). Yup, it's a credible claim. I don't see any advantage, but, well, at a marina where the propane'd be free for the management it'd maybe be worth the trouble to use a propane outboard for the work-boat-skiff.

larry sellers
11-29-2012, 04:00 PM
Paper dealing with fuel consumption (and more) of outboards and petter diesels in work-boats http://tinyurl.com/cpm39ca

Wavewacker
12-06-2012, 12:01 PM
Is this what I have - a terminal trawler?
Nudge
Has any one else done this?
Peter

I like your Terminal Trawler! Another nic-name is "Strawler", an interesting article about a guy mear St. Charles, Mo. converting a Mac 21/22 as an ideal river cruiser. Also suggested as a Looper, to do the Great Loop for the hardy at heart. Sorry I don't have a link, google will get you there.

As to your boat, I'd fabricate a windshield, may be a fold down. I'd have go to a boat cover shop and the can probably make side and rear curtians for a camper enclosure much like those on larger cruisers. Zip roll up vinal for windows and they can put in the screens as well. I had one made for a 26' cruiser out of Hypolan (sp?) and it was great! In fact, I might keep your top and just have a camper top made to match on such a nice boat.

Around here, PVC pipe, a hose and hose clamps make an extension pretty easily.

I'm seriously considering a Strawler as well! I'm on the trail of an older 40' Willard pilothouse built for the Navy as a liveaboard, it will carry a washer and dryer and my cargo needs. But, if it doesn't turn out I'll be looking for a 24 to 30 footer for a conversion.

The Strawler article featured another guy who converted a much larger sailboat, like 46' I think, making a very nice pilothouse strawler. He trimmed off the keel and added cement for balast. While I'm sure he has money tied up in his conversion it would probably take over a hundred thousand to duplicate what he has above the water line with a conventional trawler.

Great to see so much interest here on such a conversion!

larry sellers
12-06-2012, 02:51 PM
The classical "Monterrey Clippers", similar boats, tended to chose the "frisco" engine in the 8 hp version - a compromise. But their experience tells us how much engine a terminal trawler needs, more or less.

I knew a couple who built a riverboat/canalboat along these lines - communists, they lived in Czechoslovakia. (Guy works in a bank now, he burned his boat when he decided to leave communism...well, he couldn't take his boat with him...) They say it was difficult doing boat-building in a country with a centralized communist economy. their coolingwater pump, for example, was the fuel transfer pump from a Dakota, a DC-3, probably a stolen pump. But it was neat too, they said, because you didn't worry about buying diesel - (they used a VW diesel motor) - anyway, in commie countries of eastern and central europe, one packed aboard cases of home-made vodka, not money (nothing to buy with it) or fuel. Then, each river-evening (or canalboat evening) they'd side-tie to a state-owned barge (they were all state owned barges) and smoke cigarettes and chat, the girls'd smile, and the vodka'd come out. By morning the hose had come out and the communist fuel had drained from the state barge into the "terminal trawler". The rate of exchange? About 5 gallons of fuel for a quart of vodka... Not so bad. Machine parts in general were obtained the same way - you knew a guy who would do a "g-job" - make the parts at his state job - and he'd do that for vodka. Engines were cheap too - as the state said that body and engine numbers had to match, so there was zero value for a used engine from a wreck. Again, a quart bottle would buy just about any motor. Of course, this was Czechoslovakia and East Germany and so forth. Things may have been much less accommodating as one moved east... Anyway, my old pal took pictures of his burning boat. I've seen 'em.

Wavewacker
12-06-2012, 03:30 PM
Trading commodities was common through out Europe I'm sure, I paid much of my penthouse apartment rents 40 years ago with Jim Beam in West Germany!

I'm insisting on a smaller power plant, gas or diesel, I looked into propane and like you said Larry, loss of power, cleaner but it has more of the boom factor when it comes to storage, overall not a good idea in a decked boat.

For a strawler, TT, I'd rather go with a 4 stroke OB.

You'all think a trolling motor with an extension would help in the dock areas for a bow thruster on a 30'er? I've never tried turning a 30'er in it's own foot print with a small OB.... ?

larry sellers
12-06-2012, 07:45 PM
If somebody said that working for the us army was a lot like the tales about Czechoslovakia they might be right. There were many "g-jobs", and many of the machinists had boats. I seem to remember people making titanium parts for their own and their friends "projects". I even remember stories about liberation of gasoline, gasp!

One guy, it was said, even built boat trailers at work...for a while.

And in Korea, back in the day, the girls were one case, two case, and for the top shelf - 3-case girls. Case? Jack Daniels. The old stories about cuba and gitmo are too dark for this arena...and the men and the girls and the kids - all grown, gone. Does anybody remember the narrow gauge railroad at gitmo?

Nominal 10 hp 4-stroke OB would, I should think, be fine. Yet my own opinion is that the prop size/rpm is going to make a very poor coupling or match with a hull that measures 20 to 30 feet. Worse, the OB is going to be temperamental as it ages, and, in a difficult weather situation, is liable to fail. My esthetic sense says slow inboard <20 hp, direct or gear-reduction, 12 " prop (or bigger). There are numerous industrial engines that might be "marinized" to suit the job. I'd favor air-cooled for simplicity...kitchen rudder or transmission. Given that the kitchen design works really well <10 kts that'd probably be best - as these boats are not going to be fast at all.

I have experimented with bilge and stem keels, wings more properly, that have aspect ratios and area that can be exploited to achieve considerable maneuverability - similar to thruster effects. The method was to mount a single large high-aspect fin about 1/4 of WL from cutwater on the keel-line, and mount a pair of low aspect ratio fins parallel aft, under engine, perhaps 3 feet from transom. With that arrangement the boat (32' steel with 100 hp ford) would turn 180 at full speed so quickly that the boat was making stern-way, yet was so solid in terms of heading that I could go below briefly to re-fill my coffee cup. At low speed the aft fins had almost no effect. As speed increased the boat tended to lock onto a course. It was an (eaton model B) outdrive boat.

I toyed with the idea of making the fwd fin steer-able. Didn't do it. Similarly, toyed with the idea of a jet-thruster ... the idea being an electric pump with valves and two jets. One jet left, one jet right; all mounted under the fo'c'sle deck.

g'nite.

James May
01-20-2013, 05:36 PM
I have finally completed rebuilding one of these myself after reading this forum a while ago... worked out well and saved a boat from going to the dump.
EX Noelex 22https://www.facebook.com/james.maylpsnz?ref=tn_tnmn#!/photo.php?fbid=10200433843559245&set=a.1031210991130.2006386.1551041686&type=1&theater

James May
01-20-2013, 05:53 PM
Sorry, i'll try that again

troy2000
01-21-2013, 12:09 PM
Sorry, i'll try that again

Looks good to me... congrats on getting it done. Do you have any pic's you took while working on it, or a blog somewhere, or....?

larry sellers
01-21-2013, 02:04 PM
Yes Mr. May, a fine job! A rather longer story of your project and additional pictures would be very welcome! Please tell us more...

James May
01-22-2013, 06:19 AM
Hiya,
well if you have time....
unfortunately i have very few photos of the build (suprising considering i am a photographer)
we have had the boat a few years, we originally brought it from a older couple who had let the condition get away on them. They were so pleased for the boat to go to a new home that i actually had to talk them UP in price!!
that first spring i started dealing to the obvious rot in the topsides, but it quickly become clear that the rot was terminal.
I patched it up enough to enjoy a summers sailing with my very young family and was still only a few hundred out of pocket.
As the hull looked remarkably sound, i had not done much more than tapped the few stringers i could find to check for any soft spots and inspected (not too closely) the outside of the hull.
sometime into the first summer i decided to open up a little more space in the outboard well to make space for a slightly larger 4 stroke outboard and discovered that the hull itself was Glass, not just GOP.
this discovery, along with the degree of rot in the topsides was the encouragement i needed to build something i have always wanted to build. (i'm one of those, "it's the journey", not the destination types)
so i sat down with a pad and paper and started to draw up a slightly more usable version of the yacht.
i had to build all of the cabin without glue, in a rented house's garage, as at the time we had to move out of our house while it was demolished (canterbury earthquake damaged) and while the new house was being built.
once we had moved home i simply had to pull off the old cabin and fit the new one into place and glue as i went, then built the decks and sides etc.
i used BS1088 Meranti and Gaboon for all the timber except the trim and fold down seats which is Kwila.
I think she still needs some more balast as the new top is a lot lighter than the old one.
I stuck to the drawings as best i could, but a lot had to be made as i went, and i am terrible at maths, so the thing the pictures don't show is the relief in my face that the boat is atop the water, not under... Someone did ask me once how i would know if i had done it right... i said when it slides off the trailer if i can see the entire boat, right way up, it probably turned out ok...
After doing some maths, i think she took around 1300-1500Hrs (im sure most of that was sanding) and all told including original purchase maybe as much as $3000. not including the motor.
a quick run down from the bow:
There is a door in the front of the cabin to get in and out without walking down the sides or over the top of the cabin. Then inside the forward berth remains pretty standard, the drop Keel is still in and also serves as one side of the galley which has hot and cold water and a wee drop in table.
There is a companionway and seating opposite.
Further back opens onto the deck, which is too low to be self draining so is drained into a tank underfloor and pumped overboard from here.
The deck i used ripped down ply for decking and filled in between with filler to give it a nice white grout look, there is a seat across the rear and a dropdoen seat on either side of the deck. then there is the motor well which ahs been adated to take a 25Hp Mercury (only 2nd hand one i could find that takes remotes and is electric start)
then a little boarding platform.

James May
01-22-2013, 06:24 AM
now that she is complete, i think i'll make her a little stitch and glue dingy to tow around and start looking at plans for as larger boat i can make fit a trailer without permits.. which of course will also be displacement.
i know i have only just joined the forums but i have been reading them for a really long time, so thanks for the inspiration, especially the member who had been using his hartly without sails!!

James May
01-22-2013, 06:28 AM
I still have a couple of wee jobs to do like the tidy up the boot topping and other bits of paint touchup

whitepointer23
01-22-2013, 08:42 AM
I still have a couple of wee jobs to do like the tidy up the boot topping and other bits of paint touchup

Great job. Looks good. Love your work on top gear to.

James May
01-22-2013, 03:50 PM
Hahahaha,... while i'm a car nut, (also built rally car over last winter) unfortunately i am not the wealthy James May...

Dr. Peter
01-24-2013, 08:15 PM
James,
I have been focussing on my sailboat lately and my Hartley conversion project has stalled for the moment, but it is not out of my thoughts. I just got back from 9 days sailing around the Gippsland Lakes, Victoria, Australia where you see a lot of converted boats - that is sailing hulls with new top structures. Very inspiring - as were your photos. Well done - 'Sweet as ... bro'

sltak
03-04-2013, 08:30 AM
I was looking at a Noelex this morning, wondering how it would convert to a power boat. Pity to cut down such a beautiful sail boat, but on the other hand if it is past its sailing days....it seemed to me to be such a sweet hull it wouldn't need much power. Tell me, how does yours go with the 25hp mercury (I would have though this to be way to much)- does she plane, or do you just use a small amount of the power. And how does the outboard well cope with the stern wave? I have been thinking about this for a while, would be very interested.

sltak
03-04-2013, 08:36 AM
I forgot to add, I am also considering a Hartley 18, which is what drew me to this thread (Dr Peter) - the general consensus seems to be that 10hp is about all the Hartley 18 can absorb. In theory. Has anyone actually tried a 15hp on one of these? I want to do displacement speed most of the time, but also want to work up a river and might need to stem about 5 knot current. Is it feasible by over-powering a displacement hull like a Hartley 18? I know know it is not feasible in theory - I want to know what happens in practice.

larry sellers
03-04-2013, 10:41 AM
My opinion is that the general rules apply - double the speed requires power squared. And that has a large effect on fuel consumption and thus range. Rivers are full of debris - punching a hole in a glass hull is pretty easy. If possible wait for tidal influence to quiet the current and go at a moderate speed - safer. Do not be hasty. Best.

fredrosse
03-04-2013, 11:03 AM
"double the speed requires power squared", implying 2Xspeed = 4Xpower.

Not so with a displacement hull, actually the relationship is a cubic function, so double speed would require 8x the power!

This is all considered with a displacement boat within the realm of displacement boat speeds, and that approximately means staying at less than 1.35 x the squareroot of the waterline length. Trying to push a displacement hull much faster results the cubic function raising to a fourth or fifth power function, power required skyrockets.

For planing hulls there is a different set of functions, however I think, with a planing boat, double speed would still require more than 4Xpower.

larry sellers
03-04-2013, 11:14 AM
Yes, excuse me. I was careless and I knew better. However the principle with respect to range and safety remains - obviously buttressed. I was perhaps thinking about the energy available to punch a hole being squared... I used to do rivers a lot. When the current was too strong I simply stopped in a safe place and found something to do, read, whatever.

sltak
03-04-2013, 04:51 PM
Thanks for the reply guys. I have no plan to go up a river at planing speed. Just want to be reassured I can move ahead in the upper reaches of a river (away from tidal influece) at more than a snail's pace.

Not disputing the theory, but very keen also to hear from Dr Peter and James May as to precisely how, in practice, their particular hulls behave under "too much" power.
The Hartley 18 and the Noelex 22 are rather different hull forms, albeit both sailboats - which makes the question even more interesting. I am familiar with both, as sailboats - but had not thought before about how much power they could take, and am right now considering one or the other as a conversion to a power camping cruiser.

If it is not straying too far from the thread, I would be interested in more advice on river cruising - in a boat such as a trailer-sailer converted to motor boat. Anyone in new Zealand tried the Waikato above Ngaruawahia?

Dr. Peter
04-01-2013, 03:53 AM
In its previous life as a sailboat my Hartley did plane once. It was on a screaming reach in about 20+ knots of wind. There were three of us on board and everything was sheeted on pretty hard. We were going really fast.

As a motorboat, going upstream with the throttle wide open, there is a lot of noise, a big wake, and only a marginal increase in speed. To be frank, I usually set the speed based on how irritating I find the engine noise. I would rather travel a bit more slowly for a bit more peace.

That might be a case for a larger engine like a 15hp - more oomph at less revs. More speed and relatively less noise. It might have a better charging coil too if charging batteries is important.

Another approach is to use a particular engine with a different pitch. I have used a 5hp single cylinder two stroke and IMHO it is easier on the ears than an 8hp twin cylinder two stroke.

This picture shows the current state of the boat. A single cylinder 5hp motor, a slot top, and a cut down mast as a ridge pole.

PAR
04-01-2013, 04:45 AM
If you want to get a bit more speed out of her, you might consider using some horizontal appendages under the aft quarters, much like the Bartender (below) does. This would offer additional area to prevent squatting so much and she'd be able to plane off, given enough power.

http://bartenderboats.com/images/RonZ%2020.5.JPG
http://bartenderboats.com/images/DaveB%2026%27Lc.jpg

There would be some experimentation necessary, so make them too big and cut them down until they work well.

sltak
04-01-2013, 06:56 AM
Thanks again for your replies.

I like the slot top on the Hartley, and appreciate the comments regarding engines. Under water appendages aft is something I have considered too.

Since the last posting, I have bought a boat, done a quick conversion and just completed a 3-day trial on the upper reaches of the Waikato and Waipa rivers. I can now add a little to this forum.

I eventually liost patience and bought the first trailer yacht that was reasonably priced. A Mark 3 Kestrel (18' trailer sail boat.) Immediately realised that was a mistake - these boats have a stub keel and require a good launching ramp to float on and off trailer. Sold it same day, and next day bought an old mark 1 Kestrel - somebody had already chopped nto the transom, the sails were past being useable - so a good candidate for conversion. This early version of the Kestrel has no keel, floats in a few inches, and appears to have no ballast either.
I took out most of the bulkhead at the rear of the cabin, widened the hatch and fitted a couple of moulded ply seats, facing forwards. The seats were picked up for $10. (Nothing "marine" on this baby.) Accomodation for two, and a galley, remain as standard under the foredeck.

My nice near-new Mercury goes back on the market after discovering it costs nearly $1,000 to fit these things with remotes and teleflex steering. You need special Mercury conversion parts. I have no time (or money) for that sort of nonsense.
Picked up an old Yamaha 9.9hp 4-stroke that already had remotes, made up a wooden quadrant and fitted her with rope and pulley steering. (They use the same system for the flight controls on light aircraft don't they?)
Loaded the bow with 50 litres of water, in containers, for ballast - and off up the Waikato. From Ngaruawahia to almost Lake Karepiro took about 7 hours. (I turned around at that point - lesson learnt: the issue is not being able to steam against the fairly rapid current - can do that OK - my fear was running back down the river, going the wrong side of an obstacle, and not being able to stop. As you get further up river fropm Cambridge, the river becomes more and more rapid. The banks looked pretty hard and rocky, and suddenly the old fibreglass hull felt a bit fragile.

Returned to Ngaruawahia next day, and did a trip up the Waipa tributary. Quite a different river - sluggish at first, very easy - but both sides and sometimes the middle littered with tree trunks and snags, so proceded slowly. Up past Whatawhata it starts to become a bit rapid. The 65' armed and armour-plated paddle-steamer Avon worked right up to here during the Waikato war in 1863/64, well-documented by mishipman Cecil Foljambe. The river appears not to have changed much.

Conclusion: old trailerable yachts can indeed make excellent little displacement launches. 10hp is enough to draw a sizeable stern wave and I spent most of my time at less than half throttle, with almost full hull speed and no stress. Like the previous posts, I can say 10hp is enough - 15hp might be nice but only because it might be even quieter. I was very happy with my 9.9hp (which has alternator and electric start) and it was powerful enough to push against a fairly rapid current at "the narrows", up-river from Cambridge. Galloping back down with the engine idling just fast enough for steerage was more of a worry. Incidently, I steamed a total of about 15 hours and used a little less than 15 litres of petrol.
One further point - these motors can be fitted with a fine pitch propellor. It seems you have to retain the same diameter and gear ratio, but at least with fine pitch you can get a bit more useful thrust from your low powered engine, at the relatively low speed of a displacement hull. My motor came with a standard propellor (which I have not tried) and also a fine pitch, which had already been fitted, and was the one I used.

Being a person who loves sailing, I am not advocating hacking up sailboats, in general. I will retain the sailing ability of the Kestrel, but probably give her a simple and more sensible low rig, as befits a motor-sailer. Twin rudders are all the latest fashion on race boats these days - so I think the motor can stay in the middle, where it should be - and I might put twin rudders on, for sailing, if I get around to making a sailing rig. A shortish mast in a proper tabernacle (not these little stainless steel gismos the trailer-sailers have) will double nicely as a ridgepole - exactly as on the Hartley in the previous post - an excellent idea.

But there are trailer boats around which will probably never sail again - I actually saw one at the Waitakere rubbish recycling station the other day!
Such boats can make a lovely trailerable displacement launch and 10hp with a barge prop (fine pitch) is all you need.

This little old boat will be fine on rivers, estuaries and any sheltered stretches of water accessible by boat ramp.

sltak
04-01-2013, 07:04 AM
Here are a couple of pics.

Dr. Peter
04-01-2013, 08:06 AM
The essence of what we do is about enjoying simple boats. To be honest, my converted Hartley 18 sits in my shed most of the time while I continue to enjoy sailing - but that's OK. Well done, on your conversion.

James May
04-30-2013, 06:09 PM
sorry for the delay in replying...
firstly, the 25hp was only brought as it had remotes and electric start... the difference between quarter throttle and full throttle is lots of noise and about 1/2 a knot.
that said, the boat is awesome to use (if your not in a rush) and the biggest problem i tend to strike is people stopping me to talk about here and take photos wherever we go!!
SLtak: I wish i could have joined you!!!!!, i cant imagine anything more awesome than going on an expedition up a river or exploring over a few days in my old girl!.
We also have since brought a little ski boat (kids made me) which tends to be the boat that gets voted to use most often but, it does not compare to floating around on the big boat with the smell of coffee and sausages cooking!!

DennisRB
05-04-2013, 07:42 PM
Congrats on the conversions!

Would some designs lend themselves to removal of the keel? Obviously this will be dead weight when towing and motoring and the huge centerboard case takes up a lot of room in a small boat. The mast and sails will be gone so the overturning moment will be gone from that point of view. However as mentioned if the hull sits very high it may become "tippy". It seems to me that some designs may suffer this and some may end up no worse than a powerboat. Would a full stability calculation on the hull be required?

My dad has an old hard chine plywood 25' trailer sailer. This boat was fitted with a huge oversized 6 foot swing keel of 500kg! It used to plane downwind a breeze due to a fairly narrow stern with a flat run aft so it might be able to exceed hull speed with a decent engine. My dad is getting older and the boat is a bear to rig and subsequently does not get used. Dad used to take it in serious offshore conditions with waves as tall as the mast. But when converted it would be a used in partially smooth waters at most, mainly rivers and estuaries.

An inboard diesel engine may offset some of the weight of the swing keel. The only prob I see is maintaining beachability with the prop of an inboard which would preclude the idea. Also it seems this boat has a lot if history as a race boat 40 years ago.

http://www.trailersailerplace.com.au/phpBB3/viewtopic.php?f=37&t=9550

PAR
05-04-2013, 11:35 PM
As a rule you can remove only a bit of the ballast, not all of it. In many boats, you lose what you gain. By this I mean what you take off in the rig and sails, gets replaced with a cabin structure, so you can't really remove the ballast. Now, this doesn't mean you can't reposition it, say cutting out a ballasted fin and placing this weight, in the bottom of the bilge. The boat still rides on it's "lines" but you don't have a big 'ol fin dangling under it. The same would be true of your dad's centerboarder. You'll probably still need most, if not all of this weight in the boat, but it doesn't have to live vertically in a case. You can remove the case and arrange the weight horizontally, in the bilge.

fredrosse
05-06-2013, 11:37 AM
I converted an 14 ft O'Day Javelin to electric power, removed the centerwell and steel plate centerboard, fiberglassed in a propeller shaft for a 14 inch prop, and added two bilge keels for steering/stability. The boat is very well behaved, and works with 4 adults aboard, moving around at 5 MPH. A larger boat with a few horsepower would behave similarly, with proper bilge keels.

This build is outlined on the Yahoo "Electric Boats" website, with all details under the files "Building an Electric Javelin", $1000 plus 100 hours work.

sltak
05-13-2013, 09:57 PM
Congrats on the conversions!

Would some designs lend themselves to removal of the keel? Obviously this will be dead weight when towing and motoring and the huge centerboard case takes up a lot of room in a small boat. The mast and sails will be gone so the overturning moment will be gone from that point of view. However as mentioned if the hull sits very high it may become "tippy". It seems to me that some designs may suffer this and some may end up no worse than a powerboat. Would a full stability calculation on the hull be required?

My dad has an old hard chine plywood 25' trailer sailer. This boat was fitted with a huge oversized 6 foot swing keel of 500kg! It used to plane downwind a breeze due to a fairly narrow stern with a flat run aft so it might be able to exceed hull speed with a decent engine. My dad is getting older and the boat is a bear to rig and subsequently does not get used. Dad used to take it in serious offshore conditions with waves as tall as the mast. But when converted it would be a used in partially smooth waters at most, mainly rivers and estuaries.

An inboard diesel engine may offset some of the weight of the swing keel. The only prob I see is maintaining beachability with the prop of an inboard which would preclude the idea. Also it seems this boat has a lot if history as a race boat 40 years ago.

http://www.trailersailerplace.com.au/phpBB3/viewtopic.php?f=37&t=9550

Dennis I think you could remove the heavy centreboard in a hard chine trailer boat. The stability of a boat comes from its hull form in combination with the position of the centre of gravity. A ballasted keel boat is not simply a pendulum. With centreboard boats, launches etc hull form is what gives it the stability - a keel with ballast low down would improve the ability of the boat to right itself from a knock-down, and is usually designed to provide the ultimate ability to recover from a capsize. Maybe your trailer sailer would not recover from a capsize. But if you are using it as a cabin boat with no mast, you are not going to capsize in the normal sheltered waters you would be taking your boat. The removal of the weight will affect the boat - in your case probably for the better, and it may affect the trim. The removal of the mast will give the boat better initial stability and will affect the boat's motion, possibly making it quicker in its rolling motion - you will notice that when beam on to the wake of a speedboat, for example. I would have no hesitation in removing the centreboard and mast on your sort of boat, if that is what you want, and you can always trim it up (as I do on my kestrel) with a couple of well-placed 20 litre water containers (I have to carry mine at the bow.) With the centreboard out and the rigging out, you will have higher intitial stability than before. Pushed over to the point of a capsize, you may or may not be in a better position than before. Most trailer sailers will not recover from a capsize anyway. Howe many launches have you seen capsized? You would have the displacement to spare to put in a small diesel if you want - but any weight you put in your boat will be for trim rather than stability (as long as it is inside the hull.) An easier conversion for a trailer sailer would be a 10 hp outboard mounted on the transom. It is possible that with a larger motor you will be able to defy the theorists and exceed the hull speed (See my next post) but if you really want to go running around at high speed then a runabout would be better.

DennisRB
05-13-2013, 10:05 PM
sltak, your post pretty much summed up my opinions exactly. However I am concerned that PAR does not agree. I don't really need very high speed, but my observation that this boat can plane undersail with a 500kg centerboard in it, may make it a good candidate for a larger than usual motor.

The boat is very stable with the centerboard up, even under sail. We always sailed with it up downwind.

A diesel would be good, but in reality, it will be very difficult to get the shoal draft I want. So a 4 stroke with forward controls might be much better

sltak
05-13-2013, 11:24 PM
Dennis, you've got it. A centreboard is not usually there to make the boat more stable. It is usually there to provide lateral resistance when sailing to windward.
A ballasted keel provides little self-righting moment until the boat is heeled quite a lot - that is when its "stability" factor kicks in.
At small angles of heel, hull form is what pushes the boat upright.
I must say however, that a 6' x 500lb centreboard would give a great deal of self-righting ability in the case of a knockdown.
Without a rig, however, you should not expect to be knocked down.

Over powering your trailer yacht hull.
I converted a Mark-1 Kestrel (19' trailer sailer) into a launch and found that a 9.9hp Yamaha 4 stroke, with remote controls and electric start was a delight, and had all the thrust needed. This motor had more than the usual reduction, making it able to turn a larger than normal propeller - a perfect setup for pushing a launch at displacement speed. The propeller a has less pitch - to be specific I think this 10hp motor is turning a 11.75" diameter x 7" pitch propeller. That is about the ideal.

In theory the power of a larger motor is wasted on a displacement hull, and for a reasonably heavy hull a ridiculous amount of power would be necessary to make it plane. The previous post describing the Noelex describes this. (You can of course use a larger motor and just make it do less work, thus enjoying the advantage of quieter running, electric start etc.) At higher throttle setting, you would expect anything more than the thrust from a 10hp motor to just cause noise, squatting and excessive stern wave.

But wait, there's more.

My so-suitable 9.9hp motor developed a fault so I bought a 15hp Honda to replace it. I was not looking for more speed, only quieter running with even less effort. When the motor arrived I was dismayed to find that it had a standard reduction and a runabout type propeller (9.25 x 9.5). In theory quite unsuitable. And these motors don't come with the reduction or the room to swing a bigger diameter propeller. I was going to have to sell the new motor and look around for another Yamaha "barge model."
This morning I thought I would just give it a run anyway, and see how bad it really was. To my surprise it was noisier (not quieter) than the Yamaha - but still not bad, both being 4-strokes. It ran quite nicely at low throttle and pushed the boat to hull speed quite easily despite the little propeller. (A cavitation plate is fitted, I don't know if that helped.) But the real surprise came when I "opened her up". She quickly ran up over hull speed and began planing, somewhat heavily, in the manner of a fairly big yacht planing. I would think she was doing 10 or 12 knots - certainly well over hull speed - and without the expected fuss and bother. She pulled a bit of a stern wave, but not too bad - less than a runabout would - certainly not squatting. We had two adults aboard and about 50kg of water in the bow for ballast.
The only fault I could find was that with the small unsuitable propeller, you can't pull up quickly by engaging reverse, so you lose a little bit there. But going ahead, the extra horsepower was simply converted into extra speed - in contradiction to the conventional wisdom. Also, for this motor, I can get a SLIGHTLY bigger diameter, lower pitch, 4-blade large-blade-area propeller from Solas that I think will give better thrust, especially in reverse, with maybe a little less speed - (though I am not after speed anyway. A runabout is better for that.)

In conclusion: If your boat can plane under sail, and if you are not carrying too much weight, and if she is trimmed right, it is quite possible you can make it plane by applying a bit more power. I have proved it with the Kestrel using the standard model 15hp Honda.
On the other hand, for maximum efficiency this boat is better running at hull speed and I think the 9.9hp Yamaha with bigger reduction and bigger diameter "high thrust" propeller is all you need and probably best.

I think it is most likely that with the rig and heavy swing keel out of your boat, you will get better performance than I can get with the kestrel, (being longer on the water line) and my comments about the above two motors will probably relate equally to your boat (depending on weight I suppose, and assuming that yours is a normal type of trailer yacht hull shape.)

sltak
05-13-2013, 11:46 PM
Ballasting.
Dennis, I meant to add this.
If you take a 500 lb centreboard out, your boat will certainly float higher. This may or may not be to your liking. If it feels a bit tender, or if the trim is all wrong, you will have to put some ballast back in. But instead of a heavy keel, you can use 20 litre jerry cans of water, placed as low in the hull as you can put them, and forward or aft as necessary to compensate for the weight of the motor at the back. If you anticipate a lot of rolling around in exposed water, then it might be wise to make sure they are well lashed. For rivers and estuaries I don't worry about that.
Result: the roll/pitch characteristics of your boat will be a little quicker than with a mast and heavy keel, but your stability should be just as good as before, at least with the swing keel in its case - (a kg of lead weighting about the same as a kg of water!) Plus, with a little pump and some plastic hose you have all the water you want for drinking and washing. You fill up at the ramp - and empty out before going home, so easier to tow.
That's what I am doing anyway. I carry about 40 litres, but it is no problem to sling a bit more in if needed.

DennisRB
05-14-2013, 12:56 AM
Your experiment with overpowering your TS hull proved that they can plane if the shape is right for it. Knowing this I am sure mine will plane as it done so under sail, and if you take the 500kg centerboard out it should make it very easy to exceed hull speed with say a 30hp. I need to get some pics. The run is very flat aft. It would usually be cruised at below hull speed but being able to sprint when needed would be a huge advantage.

The only issue as noted will be how it sits with no keel. The boat was once put in the water with no keel years ago. My dad did not recall exactly how it sat, but does not recall any issues. Note the keel on this boat certainly did add a lot of stability. Note it is 500kg!! Not lbs. It was able to be bolted in the down position. I am sure it would have recovered from a capsize with keel so long and heavy on a small boat. This keel was made heavier than the original design. So the boat actually always sat low and dragged the transom.

A couple of large house batteries would be installed down low. It already has a 100L water bladder. The boat also has an anchor roller with chain and electric anchor winch fitted in the bow. This all adds about 200kg.

I am sure the boat will sit higher. But I think an experiment would be in order to test how she sits with the keel removed before any other mods are performed. It may be OK, or maybe not.

sltak
05-14-2013, 03:11 AM
Dennis, what is the design does it have a name? Do you know who designed it?

Yes you are right, with that sort of keel (other things being equal) she would probably come up from a capsize and drag the mast and sails up again too. But that sort of ultimate stability is not usually called for in a launch, or for that matter a small sail boat like a Hartley trailer-sailer, for example. An even better example is a catamaran - very high initial stability, with no keel or any ballast. A motor catamaran would be very hard to capsize. Of course, once upside down, it becomes even more stable!

It will sit all right. 500kg is a lot to take out, but I am sure if you put some weight back in, down low, like your batteries, water etc. you will get it sitting nicely. By the way, in answer to the majority who will tell you that the keel is necessary for stability - until about 100 or so years ago, the age of sail, ballasted keels were unheard of. All ballast was carried inside, and ships did not have appendage keels. Hull shape which has low inherent stability and is designed for a deep ballasted keel is slightly different, but a trailerable boat with a lifting keel will have enough initial stability, especially with no mast. If not, and if all else fails, a few bags of sand under the floorboards is not unheard of, as in the old mullet boats for example. All this assumes you are motoring in sheltered waters. If ballast shifts, that can change things rapidly for the worse.

A bit of weight at the bow or stern will soon get it trimmed right, though I would think your keel would have been roughly over the centre of gravity anyway - if it is out of trim that would more likely be from putting a big motor on the back, not too hard to trim out. A bit of trial and error and you will soon get it right. If it is a bit tender (tip easily if you stand on the gunnel) you will soon know, and a bit more ballast will help. But with the mast gone I would think it would be stiffer, if anything.

The danger is if it is cranky (very slow to recover when it rolls one way) - that can be a danger signal. When you turn sharply and it rolls out, and does not seem to recover quickly - that's a sign things are not good. I saw a small launch heading off to Waiheke with a deck load of bags of cement once, that was cranky like that. In my opinion that was dangerous. I really don't think you will have anything like that to worry about at all.

I would just take it one step at a time with the ballast, until it feels and looks right.

Same with the motor - is there some way you could try something a little less than 30hp to start with? You are getting into the runabout category with 30hp. Make sure the transom is strong enough to withstand the thrust (and the stresses while towing) of such a big motor.

sltak
05-14-2013, 03:18 AM
I have just gone back and re-read what PAR wrote. It makes perfect sense, and seems quite consistent with what you are proposing - ie you take the ballasted swing keel out and put at least some of the weight back in, in in the bilges, in some other form. If it was over-ballasted and dragging its stern before, then presumably you will want to put only some of the weight back. And if it is in a form where you can dispose of some of it at the ramp - then you will have gained a lot in terms of ease of towing.

Doug Meyer
06-13-2013, 04:59 AM
Hi All,

This is my first time on a forum so bare with me.I have modified two trailer sailors, one to a power launch using a Frank Pelin 17 ft hull and the second a 16 ft Hartley GTS (Hartley 16 fibre glass version) which I raised the cabin roof and converted to a motorsailor. Both boats I kept the swing keels but both boats only reached hullspeed which at 5 to 6 knots is painfully slow.I have purchased another 16ft Quicksilver same as the hartley 16 fibreglass version.I intend to modify the hull this time and remove the keel and try and get the hull lines as close as i can to John Atkins Ninigret.
Sorry not trying to break up the thread but I have been there as above I have changed motors,props and mounting positions all end up with the same hull speed.I suggest that the easiest thing to do would put a wedge aft to change the buttock angle.I have seen this done but don't know how efficient it is so I am going to modify mine from amidships to the stern.Then you could increase your motor to maybe a 15hp. Sorry I don't know how I got here i was supposed to be on the thread with the Hartley 18.

PAR
06-13-2013, 01:19 PM
Welcome to the forum Doug.

The typical shapes used in sailing craft wouldn't benefit from a wedge, in regard to getting more speed from them. It's simple physics really and nothing short of reshaping the entire after end on the boat will help.

You also may want to start a new thread about this subject as there are some tricks that do work, besides wedges.

Doug Meyer
06-14-2013, 01:32 AM
Hi Par, Thanks for that I will set up a new thread I have only just found this forum and it seems like a gold mine of info and that there are some other Mad boaties like me out there.

PAR
06-14-2013, 04:05 AM
Most aren't willing to publicly admit to the madness, but yes, you're quite correct.

Kevin Hornby
01-30-2014, 11:37 PM
New to the forum but this subject caught my eye. I have owned all types of boats but have narrowed down my needs to a motor sailor that leans toward motoring more often, is efficient under power and can get into tight relatively shallow area's. I set off to price materials to build a boat to fit my parameters and realized how expensive that was so I started researching older boat hulls out on the market. So why not convert a sailboat, I tried to find small sailboats 25 to 30 feet that would lean toward more of a power boat stern (flatter and wider), a low rocker hull to keep the hull speed up, Trailer able because I like to travel around. Swing keels ruin interiors, full keels are hard to launch and trailer so I added shoal draft keel to my list. What I found is many of probably more unattractive sailboats as far as lines and sailing performance fit the into my list. I found a few choices but, Don't judge me! I ended up picking up a American Mariner, very roomy hull, wide flat stern, shoal draft keel you can actually put your batteries and water tanks in. Considering there reputation when they where made I am really surprised at the construction, most of the area's I would call questionable as far as construction and design I have cut out. You can pick these boats up for nothing! I have cut the deck off, and gutted most of the hull. My biggest hurdle was try and get the esthetics up a notch. I am adding raised bulwarks forward, redesigned the interior and cabin top, adding a swim step/motor mount with a bottom that will be a large trim plate. Finished design will be 29'6" +-, powered with a 30 to 40hp, be functional on and off the trailer, launch time including rig less than 1/2 hour. Boat is 50% complete at this time. There are tons of small sailboats in all sizes that are great candidates for power. Really love some of the designs I have seen above, is anyone else doing this out there, I would like to here your thoughts.

Kevin Hornby
01-31-2014, 03:04 AM
here is an interesting add, I am sure there are some candidates. http://inlandempire.craigslist.org/boa/4298415597.html

Doug Meyer
01-31-2014, 03:25 AM
Hi Kevin

It has turned out to be a big job but I feel I have got over the worst. I have attached pictures of the transom before and after the modification.I haven't taken many pictures because I see her everyday. After posting this some time ago and listening to the advice from the masters I felt I needed to learn more.so I did more research and went through "Lindsay Lords" paper on planing hulls which opened my eyes. When modifying the hull I feel I have it on the edge now between semi displacement and planing.

I am down in New Zealand and have never seen an American Mariner.I searched on the net and found some pictures and you are right has a wide straight transom and not a lot of rocker but still looks to be Full displacement and also has a round chine. Have a very close look at the MacGregor 26 that's the hull shape you need for more speed than standard hull speed of about 7 knots and you will also need a lot more power than a 30 or 40hp. The other problem is the weight of the boat and the drag on that keel. The MacGregor uses a water ballast system that can drain out when planing.

The boat in my Avatar I modified a few things raised the cabintop moved the boom up modified the transom to take a motor centrally and rudder system etc. I ended up with a very slow motor boat and not a very good sailboat.

What I am trying to say is keep it as a sailboat and tick around with a nice 9.9hp 4 stroke or modify hull completely to semi displacement and remove the keel and mast. Probably need a 70 90 hp.

Also have a look a Charles Atkins "Ninigret hull"

Kevin Hornby
01-31-2014, 10:53 AM
Wow Doug you have done a lot of work! Looks great!
I am not looking to get a lot more speed than original hull speed. It will always be a displacement hull but there are displacement hulls of all different hull speeds. I have been on plenty of power trawlers that will not do over 8 knots. I have cruised a 46' Lobster boat design long range, It hull was not a lot different minus the wider keel. It was round chine design and cruised up to 13, most of the time we ran 9/10 for comfort and fuel. That said this boat will be a single digit cruiser! I used a Trim plate on a small sailboat and it really worked well! The key is getting something big enough, mild change in angle. I am using a larger motor than needed (Most likely 30 hp)for 2 reason, I have found the noise escalates considerable and fuel usage are not great over 75% throttle so I want to keep the RPM down, also longevity and control.
I had a really nice Mac 26X, I did custom work for Macgregor yachts for years and I have to say a lot of people put there noses up at Roger Macgregors boats but they work incredibly for what they are designed for. People say oh they are not built strong enough but I am not going to take the boat open ocean cruising. They reason the boats are not built heavy is you can sail all day to a destination and the next morning be back to work in one hour under power. Another thing I will miss is the water ballast trailer weight, Towing that boat I would forget that 26' boat was back there sometimes! I have to admit I WAS A BIG SKEPTIC with the water ballast and was surprised. I have spent weeks getting to destinations such as Mexico and Caribbean powering or sailing along for days and sometimes it not that fun! I can drive to the Keys and throw my boat in and not spend 2 months getting there. I am not looking for a open ocean cruiser, I am designing comfort and easy of use, full standing room, shower, comfortable bed etc. Another big one is the rig, boy is it nice to even have small sails under power sometime! I worked for a rigging shop for 8 years and I look forward to that part of the project. I will get some pictures up later.

Kevin Hornby
01-31-2014, 11:01 AM
Here are some pics.

Doug Meyer
02-01-2014, 02:33 AM
Hi Kevin, Now I see what you are after and you are streets ahead of me I really like the lines in your drawing. Cabin work looks great. I don't know what it is but a sailboat hull makes for a very nice looking motorboat.Maybe the almost vertical stem.

So glad you are brighter than me and not cutting up the hull. Don't know about trim tabs on a slow boat could just be more resistance. When motor sailing and the boat is listing trim tabs might be all wrong, Mine are actually a hull extension for more support with 2 guys fishing off the back.

Mine is a lot smaller than yours 17ft more a day picnic boat (Like a Ryds Camping) with 2 single double berths forward so can go fishing with a mate or my wife. Fishing is what the boat is for in semi-sheltered waters.I can trail it up and down the coast drop into a quiet bay and go for short fishing trips. My boat also has a lighter hull than a deep V and my speed range is cruise at 10/12 and top about 13/14 with a 25hp 4 stroke. This is the target and I wait and work patiently on.

I agree a 30 at half throttle nice, quiet and economical.(get a 4 Blade shallow pitch thrust prop good for pushing big boats with small motors.
Idea make your screen low or fold down or a canvas screen Dodger to keep the boom low. A large furling genoa would also be magic with motor running. Remember you want your motor central for motor sailing are you going to use a twin rudder system like the Mac 26. (Not trying to tell you what to do just some idea,s)

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