Help with outboard bracket design

[savagescout]

Hello,

I am going through the process of restoring a savage 23 foot half cabin (Australian built hull).

It’s from the 70’s vintage and the current hull looks like this:

http://i66.photobucket.com/albums/h241/spargs86/DSC00166.jpg

I am wanting to modernise the hull by changing the nose of the deck and also converting the hull from an inboard to an outboard/dual outboard design.

I have photoshopped the design I want to follow and this is it:

http://i66.photobucket.com/albums/h241/spargs86/Design.jpg

The question I have is in relation to the outboard bracket/pod that I want to add. I was wondering whether the bracket should follow the shape of the bottom like this:

http://i66.photobucket.com/albums/h241/spargs86/rear.jpg

Or whether the bracket should be raised about 1-2 inches above the keel line, like this:

http://i66.photobucket.com/albums/h241/spargs86/rearraised.jpg

I would really appreciate peoples opinions on this.

Looking forward to your thoughts.

Nick.

[WickedGood]

Looks like your gotta take a traditional Classic Hull and turn it into a Blob Boat.

Extending the transom to mount a pair of outboards would be nice; However I would leave the smart lines of the original boat.

Do add at least a 4 ft dive platform between the engines and the boat and make a full transom with large scuppers. If you have to have a door you can put in a door. Gheeze. ( I dont like doors. but if you do make it open outwards)

A full hardtop without that Blob thiny in your picture would keep with the clean looks and be stronger; both emotionally and physically.

I would say you have a diamond in the rough there. Maybe after a few years of working on it and 70 or 80 thousand in engines and materials you will have quiet a boat. Oh.. Yea, You may want to sandblast that trailer and weld on some supports and galvinize dip it and maybe a new axcel and bearings and tires , winch and lights and it will work fine.


There is a REason people GIVE AWAY FREE Boats like that. Might want to think about it before you have to pay to have it disposed of.

[tom28571]

You can certainly do what you propose but, along with Wicked, I think the original is a far far better looking boat. The add-on top is a little awkward on the existing boat.

One big outboard is much less expensive than two and modern outboards are much less failure prone than an IO of any vintage. Twins are rarely more reliable than a single. Work out the balance/buoyancy equation to see how far aft the new power should go and make the extension to fit that. It may be that there will be too much buoyancy and a transom mount or a bracket with less immersion is in order.

In the end, it is easy to sink more money and effort in a rebuild than searching for a more suitable boat in the first place.

[Mr Efficiency]

Twins are rarely more reliable than a single ? How did you talk yourself into that ? I suppose it is true if you are happy to have other people towing you in when the inevitable happens if you go out often enough.

[tom28571]

Twins are rarely more reliable than a single ? How did you talk yourself into that ? I suppose it is true if you are happy to have other people towing you in when the inevitable happens if you go out often enough.

Most twin engine installations have a single fuel supply and a single battery system. Most problems with modern engines occur in one or the other of these. Mechanical problems are getting pretty rare and those that do happen usually give fair warning. A single outboard and a small kicker with a separate fuel supply is a more reliable power system than twin outboards.

You asked.

[EgliVincent]

Hey Savage Scout, I understand where you're coming from in wanting to modernize the look of your boat. Key is, you gotta do it on the cheap (both labor and time). Like others mentioned already, your proposal is basically 2/3 of the work of making plugs for a whole new boat. Here's my 2 cents: Bolt a nice gill bracket off the transom and hang a single outboard, make accommodations for a kicker motor if you desire the redundancy. Pull the small windows in the cuddy section and fill back out the holes. Find some newer contemporary windows and cut them back. Pull the windshield and rework it and the top as you like. This will still be a good amount of work but at least you're not tearing into the general structure of the boat. Once you're done with that you'll probably even question why the effort was put in. For me its a nice classic looking boat, I'd keep with the spirit of it and polish it up, modernize the power and be out on the water months sooner!

[Mr Efficiency]

Most twin engine installations have a single fuel supply and a single battery system. Most problems with modern engines occur in one or the other of these. Mechanical problems are getting pretty rare and those that do happen usually give fair warning. A single outboard and a small kicker with a separate fuel supply is a more reliable power system than twin outboards.

You asked.

No great drama to have separate battery and fuel. Kickers are OK most of the time, but tend to be useless or unmanageable in bad sea conditions. The real problem with twins is efficiency, particularly if you are hoping to have the ability to plane on one motor, you then need to under-prop and that means more fuel, and you use more anyway with twins. But the security and peace of mind factor tips the balance for a lot of people.

[pistnbroke]

Why not put a pod (or two ) on the back this will mean for every 6 inches you move the engines back you can lift them 2 inches....so a typical 18inch long pod would put the motors 6 inches higher out of harmes way ...the bottom of the pod does not follow the line of the V hull but is flat and above the water when on the plane.....have a look at the pod on a stabicraft say a 556 ....get some made up in aluminium and bolt them on ..with a deck between if you like

[Typhoon]

Buy a bracket, reinforce the transom, paint the boat and enjoy owning a very attractive boat as it is.
I'd run a large single outboard, a 200 will be plenty, a 250 would be icing on the cake.
What you propose to do will cost tens of thousands to do PROPERLY and not look like total garbage.

Regards, Andrew.

[pistnbroke]

I agree trying to glass new to old poly is a disaster ...get a pod/bracket

[tom28571]

No great drama to have separate battery and fuel. Kickers are OK most of the time, but tend to be useless or unmanageable in bad sea conditions. The real problem with twins is efficiency, particularly if you are hoping to have the ability to plane on one motor, you then need to under-prop and that means more fuel, and you use more anyway with twins. But the security and peace of mind factor tips the balance for a lot of people.

You are correct that a lot of people have that opinion. A lot of people think otherwise too. It seems to be different depending on where you live. Probably peer pressure at work.

[Mr Efficiency]

You are correct that a lot of people have that opinion. A lot of people think otherwise too. It seems to be different depending on where you live. Probably peer pressure at work.

Running a barred inlet, or operating in remote areas favours the twin installation. Don't want "kickers" when needing to stay with fast moving swells, or expect tows a long way from civilization. Independence is a good policy in most facets of life. When a tricky bar is the only way home, I really think twins are de rigeur.

[tom28571]

Running a barred inlet, or operating in remote areas favours the twin installation. Don't want "kickers" when needing to stay with fast moving swells, or expect tows a long way from civilization. Independence is a good policy in most facets of life. When a tricky bar is the only way home, I really think twins are de rigeur.

I'm tired of the argument and since you insist, I proclaim you the winner.

[Submarine Tom]

Twins are rarely more reliable than a single ? How did you talk yourself into that ? I suppose it is true if you are happy to have other people towing you in when the inevitable happens if you go out often enough.

I have run thousands of commercial hours on twins and single OB's and only ever had one fail on me, bottom end gears spun. In rescue boats, I'm all for twins but that is for reasons other than reliability, more about durability and damage. Today, there is no need for twins (OB's) in recreation and perhaps not even commercial. You are far better off to spend the money on preventative maintenance than on another OB.

Kind of ironic your handle is "Mr. Efficiency"... twins are not.

-Tom

[Mr Efficiency]

Tell me something i don't know, Tom(s). Of course they are not efficient, but in certain circumstances, as I mentioned earlier, common sense compels their use. Would you expect some other poor sucker to tow you in over a breaking bar if there was no alternative to getting back in the same way you left ? Putting other people's lives and property at risk to get me out of the do-do isn't my thing. Anyone who tells me there is no place for twin installations hasn't had a big enough fright yet.

[pistnbroke]

Noosa Coastguard will tow you in no problem from 50 miles out to sea in a gale .....$50 a year...... only joking you have to have 2 engines in South Africa to go offshore...

[tom28571]

Tell me something i don't know, Tom(s). Of course they are not efficient, but in certain circumstances, as I mentioned earlier, common sense compels their use. Would you expect some other poor sucker to tow you in over a breaking bar if there was no alternative to getting back in the same way you left ? Putting other people's lives and property at risk to get me out of the do-do isn't my thing. Anyone who tells me there is no place for twin installations hasn't had a big enough fright yet.

I think we can all agree on that. I have nothing against twins in certain circumstances but most of the boating world can get along just princely without the added expense and complication. Good maintenance will trump redundancy for most people. I haven't had an, on the water, outboard failure not related to external causes in 40 years. Earlier mechanical blown engines were the result of pushing too hard for speed.

Oops, Almost lied here. Was on a small uninhabited island off Culebra a few years ago in a borrowed Whaler 13" with a brand new Yamaha 9.9. When the cord was pulled to start back, it came out in my hand although the engine started. With no tools, I was a afraid to stop it and we made it back to Culebra ok. Turned out that there was no way to repair it anyway and the whole unit had to be replaced. Of course, I don't know where you might place a second engine on a Whaler 13.

[WickedGood]

There is No Debate.

http://www.all-pro-sportswear.com/images/A12090A%20crack%20of%20dawn%20twin%20screw.jpg

[mydauphin]

There is No Debate.

http://www.all-pro-sportswear.com/images/A12090A%20crack%20of%20dawn%20twin%20screw.jpg

Still two mouths to feed, not bad if you can afford it... :P

Are we talking boats here....

[Bruce46]

Based on my experiences with similar projects I’d think about updating the windows clean out all the inboard engine junk and give the old girl a quality coat of paint. I’m sure that if you have a significant other you’d have to admit that she looks a lot better dressed up with fresh makeup. Boats are females too.

Unless you are very experienced doing glass or aluminum work buy an good quality bracket and add proper structure inside the original transom to support the bracket/engine.
As for the engine package, buy a new 4 stroke 200 and invest in a new fuel tank, the best fuel filtration system you can find, a heavy duty starting battery plus a house battery that can act as battery backup for starting.
The money saved by just having one engine will enable you to update the interior to better then new. Remember first class preventive maintenance is a better choice then just more or bigger.
Happy boating

[EgliVincent]

I second, go with one power unit. redundancy is great and makes total sense in certain applications or where major amounts of power is needed. Look at single prop airplanes for instance, there are thousands flying around without worry and if they fails the consequences are much greater than in a boat! Keep the fuel few from water, the batteries and charging system up, and tune as recommended and you will have no worries.

[tom28571]

Now when its really critical to get across the water.
http://www.hoax-slayer.com/drug-runner-boat.shtml

Taking redundancy to a new level.

[Submarine Tom]

Tell me something i don't know, Tom(s). Of course they are not efficient, but in certain circumstances, as I mentioned earlier, common sense compels their use. Would you expect some other poor sucker to tow you in over a breaking bar if there was no alternative to getting back in the same way you left ? Putting other people's lives and property at risk to get me out of the do-do isn't my thing. Anyone who tells me there is no place for twin installations hasn't had a big enough fright yet.

It's okay Mr. Efficiency, you don't get it, you don't want to and you're not going to. Carry on.

You can get off your high horse about me putting some "poor sucker" at risk rescuing me, it's never happened. Further more, I am the "poor sucker" who drives the rescue boat...

-Tom

[Mr Efficiency]

Ouch ! :p

[Commuter Boats]

My vote goes to a single main and adequate power in an ancillary to make hull speed ( a 10 horse would be minimum in this case ). It's been mentioned that a large percentage of the problems with modern outboards is fuel and battery related. I'd like to I add that in the Pacific Northwest ( as our friends from BC will agree) a large percent of our propulsion casualties are a result of driving over logs and rocks and when a twin does either of those it generally takes out both engines.

Why not put a pod (or two ) on the back this will mean for every 6 inches you move the engines back you can lift them 2 inches....so a typical 18inch long pod would put the motors 6 inches higher out of harmes way ...the bottom of the pod does not follow the line of the V hull but is flat and above the water when on the plane.....have a look at the pod on a stabicraft say a 556 ....get some made up in aluminium and bolt them on ..with a deck between if you like
My experience has been a little different than yours, I generally go half of an inch of lift for each 12 inches of setback and on the faster projects sometimes have to come up another half of an inch per foot.

I agree trying to glass new to old poly is a disaster ...get a pod/bracket
I don't know why you'd suggest that bonding new to old poly would be problematic, I do it all the time with great success. If it's not working for you you might have a procedural problem.

I also believe that the boats styling isn't bad nor would it likely be improved by the infusion of far more money than it's worth.
It's okay Mr. Efficiency, you don't get it, you don't want to and you're not going to. Carry on.

You can get off your high horse about me putting some "poor sucker" at risk rescuing me, it's never happened. Further more, I am the "poor sucker" who drives the rescue boat...

-Tom
I'm also one the "poor suckers ( an accredited search and rescue team)" that hops in the boat in the middle of the night to assist somebody in trouble and most often I'm at the helm of a single engine powered boat with an ancillary although I would prefer a triple ( twins and an ancillary )for rescue work as efficiency is less of a priority .

I've been towed before ( weather conditions prevented the ancillary from being practical ) and it could happen again....
Gerald

[Landlubber]

poor ol Jack Savage would not be happy with the mess you plan on doing to his nice boat...just restore it as it was made, they are an excellent boat as it is...single engine.

[pistnbroke]

wet on wet poly is a chemical bond ...old and new poly only mechanical so you need to do it right....one or two nice aluminium brackets /pods and internal re inforcement ....

[savagescout]

Thanks everyone for the advice. I have decided to keep the original hull design as it is (possibly look at changing windows) and throwing on a single engine. Looking forward to getting stuck into the project.

Really appreciate the advice.

[Landlubber]

Good on ya mate, there are plenty of boat window makers that can supply the right ones for you.

She is a nice boat, well worth looking after and restoring. I am sure that you will get a nice engine at the right price too with a bit of "scouting"...all the best mate.

[alidesigner]

I dont do fibreglass boats so this is not a sales pitch but can I suggest that before you do anything you pay a naval architect a few hundred dollars to do a weight study and tell you what effect your plans will have on trim and stability. (or at least attempt it yourself with a spreadsheet and freeship)

I only say this as a while ago I was asked to help out when a modified boat had its deck under water at re-launch. New cabin, new engines and it sank like a rock. It was too late, the mods had been done at a 6 figure cost.

Moving engines and extending the hull could be ok or it could be a disaster. Get it checked out and find out how it will trim before you spend any serious money.

[Submarine Tom]

Savagescout,

Wonderfull decision. All the power to 'ya. Great idea. Way easier, way less money, way better.

All the best, good luck, post pics of your progress and remember: One hour of disassembly is worth ten hours of reassembly!

-Tom

[savagescout]

Hi EgliVincent, I would be interested to hear what sort of windows you would recommend in the cuddy section of the hull... Ie. more modern styling....

Cheers

[savagescout]

P.S thanks to all for advice and support.

[Landlubber]

Hi EgliVincent, I would be interested to see ya bike!

[EgliVincent]

Hi Savage Scout,
Looking at your photoshop work, it looks as though you're trying to make it look a bit more modern. To me that means getting rid of that hard angled windshield first. Maybe some glass with radius transitions from the front to the side would give it a more modern look. Check out 'water bonnet' and 'taylor-made' glass online, they a big pdf catalog of all their shapes as well as frames etc.. From there you could rework the top and probably save the cuddy glass for last once the other work is complete and the aesthetic comes together. I like the look of the ovals you had cut in. I just finished a 22' aluminum fishing boat build where I tried to make things look more like a fiberglass boat. I'll try to post some pics of the radiused glass I used for that (water bonnet style 536 I think). Its hard to tell from the pics but most boats have a nice flat helm surfaces allowing old glass and frame to be removed and new glass installed (especially if you buy the appropriate framework).

[savagescout]

Thanks for the advice on the curved glass sections but now that i am going to do minimal mods i think i will stick with the straight glass look.

I have drawn up my revised plans. Would love some input on thoughts.

http://i66.photobucket.com/albums/h241/spargs86/DSC00166-1.jpg

Essentially it utilising the existing hard top but enclosing the helm in full. I will form up the windshield frame out of glass with appropriate flanges so that i can insert frameless direct glazed glass to the enclosure.

Existing cuddy section windows will be reglazed with tinted glass. Boat to be two toned hull. Most likely a white bottom and deck with off white/cream sides.

I will also form up a bolt on engine bracket similar to the one in the picture and will keep it 1-2" from the edge of the transom..

WOuld like to hear what people think of this look.

[seamac]

savage,
Being blunt, it's a waste of time/money and space in the barn. Don't spend a dime on this one. Post ideas of what you want in a boat ( not this project ) others can steer you there. Something about " teaching a pig to sing" comes to mind.

[EgliVincent]

Looks good, flat glass will allow you to have it cut and installed at nearly any local glass shop. One idea as far as looks, you could kind of make it look like a Down East sort of boat. Here's a link. http://www.archdavisdesigns.com/davis_jiffyv22.html . Classic lobster trawler-ish sort of look might fit with that style of boat if you liked. Another note, make sure you have a good solid hull, stringers, transom etc. I think putting a little elbow grease could yield you a nice boat as long as the foundation is solid!

[savagescout]

Thanks for the advice EgliVincent but dont quite agree with the sentiments of Seamac but each to their own i guess.

I am completely redoing the hull so will have a new transom, stringers, foam filled etc so the boat should be rock solid.

Cheers,

Nick

[EgliVincent]

We all are familiar with that saying about opinions.....and how evyone has one. Thats fine they're just that.
Everyone has different situations, some have bags of money and no time, other need to pinch and do things themelves. I know for me, I've always built a bond with things I've created myself. There are two advantages to sweat equity, one you build an emotional bond with what you're creating, and two you'll know that boat inside and out and if something goes amiss at sea you can probably identify the problem immediately.
I'm in a strange position right know, I'm pondering buying a new powercat off the shelf or building a new one myself. The price difference will be negligable but I know if I build it I will get what i want. Fortunately I have build a few boats so I have the core skillset, but my brain says buy a boat and my heart says build your dreamboat.

[savagescout]

Guys, as per my original question on outboard bracket/pod design... If i am building a full width bracket/pod, should i install it as a continuation of the bottom of the hull or should i mount it like a stepped pod sitting approximately 3-4" above the keel line? I am interested from a performance point of view and plan for the pod to be approximately 2.5 feet long.

CHeers,

Nick

[Commuter Boats]

Both plans have potential pitfalls, the pod that doesn't conform to the bottom can induce porpoising ( longitudinal instability at speed), the one that conforms to the bottom can induce a bow down attitude while underway, both of them can provide too much buoyancy aft and make bilge water run forward at rest.
You could cover your ass and build a bracket that is 3 inches above the keel in such a way that if porpoising became a problem that 3 inches could be filled in and the engines could be lower appropriately. It could be further designed so that the center compartment could flood at rest to alleviate the situation that generated too much buoyancy......
I've done more than a dozen pods, and I had trouble with porpoising on one of them and the problem was rectified as described above. With the bugs worked out all of the pods have proven beneficial to the vessel.
Gerald

[EgliVincent]

Good advice commuter boats. In addition I would add a couple of other thougths. With an armstong bracket mounted above the keel line you will usually notice an effect when putting the boat in reverse. Rather than the majority of the reverse thrust going underneath the boat and propelling it in reverse, a good amount will often hit the back of the transom and your reverse won't be quite as efficient. I think in regards to your boat you wouldn't need the additional buyoancy of having a custom bracket made that matched the bottom of the boat. If your boat was a stern drive it was designed to hold more weight at the transom than what a new outboard would be even hung out a ways. If you were a little heavy in the rear then you could move up your fuel tank and use it to fine tune the hull to eliminate porpoising etc.. I'd just buy an inexpensive ready-made bracket and be off to the races, I don't think there are a lot of big variables to consider in your situation. If you want a custom bracket check out conradyachts.com they design very nice ones.

[savagescout]

Thanks guys,

Today i spoke with John Savage (from family who built and designed this boat). His advice was to do an extension of the hull. I can't argue with the guy who designed and built these boats. Going to get stuck into the project shortly!

Will keep all updated.

[EgliVincent]

Just one small piece of advice. If you go this route, create a bracket that bolts to the transom and has a clean break from the bracket and the transom of the boat. If you try to glass this thing in and have no seam line from bracket to boat on the bottom side it will surely stress fracture and you'll have some issues at that junction point. One question, did the designer give any specifics to support that recommendation. Many times boat builders think in terms of 'If I were building a new hull plug' how might I do it. There are many theories supporting both styles of outboard bracket, and many might support with evidence thhoughts that the reverse is true. I think I mentioned it before,but I just finished a boat that had a full bracket that matched the bottom of the boat. The thing is it was engineered that way. I had a very narrow bottom width trying to get a narrow beam to length ratio and needed the additional buoyancy. If your boat was a stern drive previously, the boat was designed to carry 150-200lbs more weight at the stern than like horsepower of an outboard. Sitting that weight out a couple feet would probably just about compensate for that additional weight hopefully keeping the longitudinal COG about the same. It is possible to creat a bow heavy boat if you have too much buyoancy aft. I don't think in your case there is anything to worry about though. Best of luck on your project, I look forward to seeing it when its done.

[savagescout]

Yeah he mentioned the difficulties of getting the stepped pod dimensions correct in relation to the engine height as a step will change the way the boat performs. His thought was that he had seen many of these boats converted with a stepped pod and a full extension pod and the extension pod was always the safer bet in relation to performance.

In response to your advice above, i am actually planning to basically extend the hull much like the conversion found here http://www.classicmako.com/forum/topic.asp?TOPIC_ID=10363&SearchTerms=mako

Essentially the existing transom will become entirely redundant and will be cut out with the stringer/floor structure extended into the new pod/extension. This extension will be a perfect area for batteries/oil reservoirs etc and will allow for a totally different rear combing set-up, transom door etc.

Lots of planning first before getting stuck in. this is the most important stuff!