Ok, Now What...?

“what do you call that thing...the sort of chine thing 1/2 way down the hull sides”

To me it is just a chine.

“It gives the boat a more 'traditional' appearance - but I know you old guys like that!”

You shouldn’t talk about Tom that way.

I won’t bore you with any excuses as to why I haven’t been helping. Let’s leave it at, “I’m busy.” I have been watching from the side lines. I must say, you two have been tearing up the field. I was leaning towards Mike’s troller. Then Will posts this layout that is perfect, for me anyway. Not much I would change. Maybe the pilot house windshield could be vertical. A few old guy things like that and I could like this one.
Gary

 

Couple more thoughts on the raised pilothouse front.
The first is a modification on the wide-body salon - you often see it on bigger 'trawlers'. There is a side deck running the full length of the stbd side, but only as far aft as the salon on the port side.
I've also included space on the outboard bracket for an auxhillary, which we've conveniently been omitting up till now.The 2nd is a variation on both. With the narrow (250mm) sidedecks running down both sides of the salon and wider (about 400mm) from the pilothouse fwd.
In both cases I've drawn a ladder leading to the side deck just aft of the helm - could be handy, but if not you could put a small cupboard there.
Both are also a little shorter at 9m (hull)

These are just ideas - personally I prefer my extended cab idea - too many steps etc in the raised pilothouse for me.......

 

Suppose so - what's a knuckle then?

 

Will;

I like the arrangement. I think the full width cabin is a good approach for such a small boat. Interior space is worth having to climb the ladder and go over the roof.

One thing you might try is to use just one step going into the pilothouse and then another step up to each seat. This allows through traffic to only go up and down one stair. You could also use a flip up foot rest to allow standing headroom at the helm and lower the roof, but then the aft pilothouse windows would be very small.

Here is my latest version. I added a one foot grid pattern and I incorporated a ladder into the vee berth fill. The fill is hinged at the forward end and the ladder steps are on the bottom side. The fill pivots up to the hatch where it latches in place.

With the lower pilothouse roof the are only two steps up to the pilothouse and two down to the forward cabin. There is a third step up to the seats in the pilothouse.

Cheers;
Mike Schooley

 

Mike, I think that your boat is becoming, how can I say this, less ugly than the original. I know that is only a backsided compliment but it is my feeling about it. I still see no need for the high pilothouse and expect it to be a problem on a long, narrow high windage hull like this. I think you fear about both visibility and outboard weight on the stern are not real problems.

Take a look at how Devlin sets up his boats. They don't suffer from poor visibility and don't have such height, even on more beamy and heavy hulls.

Another thing is that I consider my crew mate important enough to have a good forward facing seat with good visibility.

I think that there is a consistent push to steer the O1 concept toward a bigger, faster and more complicated boat than the original concept. If the current proposals are for O1, what will the more extensive concept be like and where will a simpler boat fit in.

The 120 gallons of fuel will run my boat over 1000 miles, not 300. 60 gallons of water might last me a season. Together, the tankage is over 1400 lbs!! How will the boat handle in empty versus full tank configurations?

Rant of the day.

 

Well I am sorry you feel that way, but thanks for the feed back. If you go back to my original configuration it was very similar to the Devlin Surf Scooter and much lower and better looking. My problem was I had no place for fuel, and equipment so I had to raise something. I'll admit that I probably went overboard, but it was kind of a natural progression. Know that I understand your concerns, I'll try and address them.

So do I and I like to her to be able to sit abreast of me. That is why the port side seat slides fore and aft and the backrest reverses. With the table down and the seat slid aft all four seats in the pilothouse face forward and are at the same level as the helm. The two front seats can slide forward and by reversing the back rest and raising the tables, you have two booths with seating for four separated by an isle. With the table lowered to seat height and a cushion fill-in you have two berths. I thought this was a very functional arrangement.

In my mind the difference between the low end and the high end is the equipment. I don't think you can reduce cost much by reducing structure on a home built boat. If labor is free then cost is a driven by material cost, so to reduce cost you need to eliminate high cost items or replace them with low cost items. In my mind; the low end gets a small engine and the high end gets a bigger engine. The low end gets an ice box instead of a refrigeration system. The low end gets a camp stove instead of a Yacht type stove/oven. I was also considering a sun shower in the cockpit or a solar water heater on the roof instead of an expensive water heater. OTOH if O1 is going to be upgradeable, you need to design it to incorporate the high end equipment that could be installed some day. It is much easier to leave something out that was designed in than to add it as an after thought.

I thought the goal was a weight of 5,000 lbs and cruise at 22 to 24 knots. For that weight, speed and range plus reserve I calculated that you would need between 100 and 120 gallons of fuel. I provided for 120 gallons forward and 60 gallons aft to allow for trim adjustment. Maybe I am being over concerned, but I haven't calculated the numbers yet. The requirement was to maintain 2 people for a week cruise. I know when I take a week off I use both weekends, so I assumed 10 days. With 2 people for 10 days I allowed 3 gallons per day per person. With showers I think this is comfortable but not extravagant. Am I wrong?

Cheers;
Mike Schooley

 

You make a valid point here, Tom. The more complex the design becomes, the more difficult (and probably) more expensive it will be to build - narrowing its appeal somewhat. Further, it will add to the weight, which is going to be the enemy throughout this project. OTOH you really have to define what 'cruising for a week' is to be. People like yourself (and I say this somewhat admiringly) are prepared to do without a number of things in order to achieve a simplicity of design and to kepp weight to a minimum. Others won't leave home without every conceivable knick-knack and appliance. They are prepared to wear the cost of lugging all that stuff around.
I lie somewhere in the middle. I like to be able to shower - perhaps every 2nd day (though I'm reasonably frugal with my water use). I like to be able to light the heater, the bbq and the cooker. I like to take my dogs and my dinghy (lightweight, roll-up inflatable) etc etc. I'm still mindfull that everything I take aboard, I have to cart around and will adversely effect my economy and performance.
Some of the concepts that Mike and I have shown so far may lean a little too far to the condo end of the scale - my extended cab, for instance (still my favourite) is shown with a nice swoopy, curved cabin roof. Makes for a nice drawing, but I'd hate to try and build it out of plywood!
But it is equally important to make sure that we not restricted to a boat which by its design can only lie at the camping end of the spectrum.

I've been aiming for an all-up weight of around 1800kg (4000lbs). I'm sure Tom would like us to shave a few hundred more out of it too! At 5000lbs I think it becomes too cumbersome as a trailer boat and (though I haven't done the numbers) I'm not sure that we'd meet our performance goal with just one motor.
If O-1 is to be at all economical, then a fuel capacity of 80 US gallons should be enough (4 nmpg) If we could achieve 5 nmpg then 60 would be enough, if you don't allow any for reserve. As for water, I reckon your pretty much on the money - with my two dogs (who consume quite a bit of water), my wife and I can last about 5 days on the 30 gallons aboard my boat.

 

Tom,
thinking about the weight and getting back to the bottom loading.
My hullform has a waterplane area of 9.7 sq.m
At fully loaded displacement of 1800kg, you have 185 kg per sq.m
Or at 65% of AWP, you have 285kg per sq.m
Too heavy?

 

Mike,

I meant no insult, just wanted to jerk things around a bit and see if I could determine where the design was headed. At this point, there is no design, there are just kind of wish sketches. I think there is a strong possibility that many of the things in this wish sketch are not compatible with a trailerable boat to go to sea in.

Many NA's would say that to go to sea, a planing hull should have a bottom loading of at least 75 lbs/sq ft loading on the planing waterplane (367kg/sq m). That makes Will's boat over 5000 lbs and Mikes about 6700 lbs, I expect. I think that is incompatible with the supposed simplicity of O1. I have trailed a 4500 lb boat and don't like to do it other than on short trips. Such required loading for operation in an offshore environment also pretty much eliminates any economy or comfort of planing ability at the lower speeds. "Liz" runs about 41 or so lbs/sq ft, so, even if we do take her into some rough water at times I know that she is not suited for the big stuff and make no long planed excursions into it.

This has been part of my argument. I just don't see an 8 ft 2 inch beam, 30/32 ft monohull that can operate at 30kts and cruise at 22-24kts in any substantial seas as being compatible with the simple goal of short week end to a week cruises with a substantial trailing distance on each end. If you want to go to the same nearby places all the time, then a larger non trailerable or merely transportable boat will do. Then the higher speed goals make more sense as you may want to extend your range more.

The smaller boat that is more easily and economically trailed greatly expands the cruising range without the complications.

We found this out when I was transferred to a city too far from our cruising keelboat on the coast to make weekend trips. We sold the keelboat and bought a 22 ft swing keel Catalina as a compromise. Turned out to be the best thing we ever did in boating. We went farther, faster and cruised areas that we could never have been able to get to in the bigger boat in limited vacation times. We did not mind the smaller size and more limited acommodatio since we were on the boat for much shorter times. Water and fuel and showers can be had at intervals.

This experience led us to buy a campervan when I retired. It has all necessary ammenities other than a shower. In it we have visited all 49 states, all but one Canadian Province and Mexico. We travel rather than set up camp as the owners of the big rigs tend to do because of the complication of setting them up. Around the campfires, our discussions are about our travels and what we have seen and experienced rather than about our camping rigs and how to fix the many things that go wrong with them. We see the same thing among our cruising boat friends, both sail and power. The bigger and more complicated the rig, the more people seem bounded by them and their problems and limitations. In our small boat we cruised the Florida Keys for five days without backtracking and then hauled our boat 700 miles back home and still had a day to rest up before going back to work, all in one week's vacation.

It isn't that I don't like air conditioning and a furnace but we can take our small boat to Georgian Bay in the summer and Florida in the winter. For nearby cruises it's easier to just pick suitable weather than to provide for all eventualities in one boat. I've traveled on boats with other peoples dogs/pets and they also tend to dictate the limits of what and where you go, so we forego them also.

Sorry to run on for so long but I think the background may make my comments more understandable. And Mike, I still think your boat is too high on a long, narrow beam hull.

 

At this point Tom, I think it is time I riminded you about participation rule #1

I understand your desire for simplicity and lightweight, as I've said before - so come on - it's time to put up - let's see your sketch(es).......

Disclaimer: As always, the above is put forth in a lighthearted manner, I hope you receive it as such

I agree that the heavy bottom loadings that you refer to would probably make for a more comfortable high-speed rough-water performer, but I don't think anyone is suggesting that the 22 knot (max) cruise and 28 knot max that we have set for O-1 should be achievable regardless of sea state. One of the fundamental objectives that we set ourselves was that the boat should be able to maintain planing down to about 12 knots - partly in order to allow economical speed variations to suit the conditions. (That doesn't preclude a slightly finer entry to improve rough-water performance).
That is why I've worked on a displacement of 1800kg. I believe that it will allow for a reasonable compromise between utmost simplicity (and light weight) and lard-assed complexity. If he was prepared to do without things like hot water etc, a clever builder could probably pare that back to about 1500 and install a smaller motor.

To some extent I agree with your thoughts on towing large boats - I reguarly tow our dive boat (at a combined weight of 4300kg - note kg not lbs) all over the state. And I've trailed my own 27 footer (LOA is actually 29'10") up and down the East coast of Australia. It is a more involved process than tossing a ski boat on the back, but with the right vehicle it isn't a particularly big deal. However, it requires a far greater investment in tow vehicle, trailer etc etc. Which brings me back to the 1800kg displacement I've had in mind - on trailer its combined weight would probably be around 2200kg - I think a reasonable compromise.

By preparing preliminary sketches we aren't exactly breaking new ground - it's certainly how my Westlawn course says you should go about designing a boat.
So as I said up top - show us your ideas - and bare your *** for the darts that will surely follow!!

 

Tom;

I'm not insulted. I understand your point and I agree with Will. If you have a big enough truck and deep enough pockets then towing a big trailerable boat is no problem, but O1 isn't for the deep pockets crowd.

In Dave Gerr's book "The Nature of Boats" on page 107 he provides a curve of comfortable heave on a graph of waterplane area versus displacement. At 2.5 tons or 5,000 lbs he shows that the waterplane area should be below 120 sq ft. This equates to 41.67 lb/sq ft. At 12.5 tons, 25,000 lbs the waterplane area should be <330 or 75 lb/sq ft.

If we use Dave Gerr's curve and Will's waterplave area of 9.7 sq m or 104 sq ft, then we should have a weight >2 tons or >4,000 lbs for comfortable heave. Treating this as the minimum or empty weight and adding 100 gallons of fuel (600 lbs) and 60 gallons of water (480 lbs) puts you at 5080 lbs. With personal equipment and gear I figure the maximum weight would be 5,500 lbs. If you used a "Fastload" aluminum trailer http://www.fastloadtrailers.com/model_sheet.htm the trailer would weigh 940 lbs. This brings the total weight with trailer to 6,500 lbs. Now I agree that this is too much to tow with an average vehicle, but it isn't too much for a large SUV or pickup.

Now to go to an empty weight lower that 4,000 lbs, I think you should reduce the waterplane area. If you go to a lighter loading then you need to flatten the bottom and then it is going to start pounding.

Cheers;
Mike Schooley

 

As one of the greatest all-time fence-sitters, I'm going to partially jump ship here and side with one leg on Tom's side of the fence.
It is true that if one of your objectives is to be able to maintain a given cruise speed almost regardless of the conditions, then heavier is almost always better. But heavy also comes at the cost of economy.
By running a reasonably low bottom loading and with a relatively light displacement you can vary your speed without falling into semi-displacement mode and suffering much higher fuel consumption. This boat would be very unpleasant running at 25 knots through a 3 foot slop - leaping out of the water and pounding like mad. But being able to slow down to 12, 15, 18, 20....whatever means that you can slow to the point where the boat no longer flies off the waves, but simply goes up one side and down the other.
My father often relates how the best sea boat he ever owned was an 18 foot runabout with a small cabin. It had a very shallow deadrise and was quite light - able to maintain very low planing speeds, you couldn't discern the transformation from displacement to planing.
Anyway, I digress...
As always, there is a compromise to be suffered here. At 1800kg (or thereabouts) the boat is not as light as it could be, so it won't be as economical as it ultimately could be. It won't be heavy enough to run fast in rough water. It won't allow for every conceivable option to be carried because that would make it too heavy.
But it will be easily manageable. You will be able to tow it behind a mid-size 4wd or large sedan. It will be reasonably economical. It will offer enough creature comforts for those who don't want their boating to be confused with camping. It's a compromise and I still think it's about right

 

In designing a couple of houses, I've found it much better to start with a small plan that meets minimal requirements and then adding space and features where they are most needed to satisfy desires while ballancing the added costs (all kinds of costs). Starting with the ultimate and then backing off to reality is a much more difficult process and far less satisfying since the feeling that we are continually giving up something grates a bit.

OK here is the boat that I now use. It's been on the forum since before the O1 project started. Why do I reintroduce it? Because all in all, I don't want to add very much to meet the O1 goals, at least to my satisfaction. It has all we need now and with minor modifications meets all but high speed in rough water.



What to add or change?

*More power - a 90hp max I now can get 24-25mph in ripply water so 90hp will easily push it over 30.

*More tankage - My range is now 200miles and fuel load will need to be increased to about 36 gallons plus the differential for the bigger engine.

*Water tankage is now 30 gallons and I don't see the need for more.

Hull changes -

*A bit longer to support added engine and fuel load. Increase bottom thickness to 3/4 inches by laminating a layer of 1/4 ply over the formed bottom to handle added stress in rough water.

*Increase the aft deadrise a bit as the added displacement allows to, say, 12 degrees.

*Maybe look into adding a pad under the aft keel and increasing deadrise further.

*Reduce longitudinal angle of the planing chine flats if they introduce handling problems in high speed maneuvers (chine tripping).

Whether this boat will have the excellent low speed performance of "Liz", I don't know, but I have doubts.

 

I can tell I'm going to loose this argument, but this battle has raged for decades and has been lost by better engineers than me. I'm not going to build O1 anyway, so I'll just go with the flow.

Tom;
Can you add a shower to the list of changes? I thought we had agreed on a hot shower.

I guess how you equip a boat depends on how and where you intend to use it. When I go to Mexico, once I leave San Felipe I'm not going to get a shower or potable water until I get back. The next fuel is 225 miles and the gulf doesn't get interesting for until you go 400 miles. It is worth it, the diving and fishing is spectacular. O I forgot, no air refills for 800 miles.

If I built O1, I'd get the Admirable to go with me once. They when I went boating I'd be a bachelor. This might work for a weekend now and then, but not for 5 weeks of vacation a year. I see no value in building a boat that I'll never use. I should either waste, I mean invest more money of none. That is why Portager is 36' long, has all the comforts of home and a SCUBA tank compressor onboard.

Cheers;
Mike Schooley

 

It's all about the money

Mike, it's good and well if you can spend that much on a boat.
For O1 I believe we set a price of no more than 50K$ if you do it yourself. To me that is still quite a lot of money. Personally I'd like it to be a lot cheaper than that for homebuilt, but hey, I might not be totally realistic here....

I also think that there is a huge difference how we all use our boats.
I for one use mine in the baltic sea (swedens east-coast). We also have one of the worlds finest archipellagos here, thousands of islands. And I might not (typically) go more than say 100 NM on a cruising week, probably at lot less. Because when I go on a powerboat the goal is the largest goal. I go somewhere anchor in a beautiful bay, fish some swim some, take a long walk looking around the island e.t.c.
Just "powering" around is not my idea of cruising (in a powerboat that is). Sailing, well thats a differnt story.

Mike on the otherhand needs to go to Mexico during the cruising week. Probably 'cuse there's not to much to see on the way. So he'll need a whole lot of fuel.

We need to decide who (what kind of user) O1 is supposed to appeal to.

My own sketches will follow in a day or so

Erik