Is there an existing hull shape that fits this bill?

As a follow on question... does anyone know the lightest possible jon boat there is that would be 14ft long and medium/average in beam? In this case, wetted surface area is of no concern. Just a side thought while I am wrestling with this topic.

Thank you!

 

I reckon you are going to have to design it, maybe a panga http://en.wikipedia.org/wiki/Panga_(boat) or garvey with a v bow but extra narrow beam, say 3' http://www.glen-l.com/designs/outboard/jimbo.html crossed with a banka/jukung http://en.wikipedia.org/wiki/Jukung with swing in cross beams http://www.trimarans.com/swingwing/presentation.aspx with floats that nest neatly to the main hull & finish at your maximum beam, the garvey style with strait & vertical sides might be the best load carrier & your floats could be asymmetric with matching flat inboard faces, for berthing the ship side float could be retracted/swung in leaving the other float out for stability. Jeff.

 

http://smalltrimarans.com/blog/?p=5746

I'd think any canoe hull would work, at least for the bottom wetted shape.
The tri is for a high freeboard so it won't fall over without the amas,
and to give you the wide load platform.

That SwingWing tri is awesome.

 

Any requirement on stability?

What qualifies as "Ability to carry 1500lbs or so when fully loaded"? Sheer above static waterline? Some amount of freeboard? USCG requirements for manual propulsion / 2HP or less? USCG safe loading requirements for more than 2HP?

 

If you haven't rowed a good round bottom rowboat along the lines of a Whitehall, St Lawrence River Skiff, etc you might be surprised how efficient those boats can be at displacement speeds. Wetted area is substantially less than a jonboat.

 

Any requirements on accomdations for propulsion? Examples would be:
- mounting location for clamp-on outboard (electric or gasoline)
- oarlock mounting locations with sufficient spread and appropriate height
- occupants can site/kneel close enough to sides for efficient paddling

 

I know it's frustrating emailing Kurt but if you presented him with your SOR he might be able to modify plans for his existing power proa for your needs?

 

My vision (dream??) is a boat that sits up high on a nice, efficient hull form when carrying 400-500lbs.

In my imagination, I see it getting loaded up to 1500lbs (charter guests, luggage, provisions, etc...) on occasion inside the harbor when transporting guests and their belongings to/from the boat. Also, to bring them ashore for fun.

In my imagination, I see the nice, thin hull waterline changing to a very beamy boat as you sink it with weight. Performance will be all gone at that point, but it doesn't matter anyway, because I am in the harbor at "no wake/5MPH" speeds anyway.

As for rules, USCG "more than 2HP" would definitely apply. I have a Honda BF8 I would like to use with this design. Would keep a paddle or two aboard in case of engine failure only. Otherwise, it's all power all the time.

 

Yes, those hulls are getting close to what I'm thinking of.

Basically take the yellow proa in the pictures (with Kurt Hughes at the helm) and put a huge flare in the hull. When it's loaded light, it rides on the normal waterline like in the picture. When it's loaded down, a much larger waterline profile dips in the water to carry the load.

See, I need a boat that is light and efficient for 260lbs of people (wife and I), plus some provisions. Then, when it's loaded down with charter guests and their luggage, I'd like to sink it down and lose the efficiency for the ability to carry all that extra weight.

 

8HP Honda BF8 4 stroke plus standard 3-5 gallon outboard tank

Wheel steering would most likely be required because putting my weight aft with the outboard would be problematic for an efficient hull.

Outboard should probably clamp on stern to keep noise levels down. Kurt's experimental proa (pictured) looks a bit noisy and it might make you dumb/sick from breathing the exhaust.

Oars not required. Paddles for emergency situations only.

Occupants should be able to be seated with provisions for carrying standard size suitcases (or hopefully, they will read my website and bring large duffel bags!). Still, picture several people, each with a large "hockey bag" style duffel bag and cases of wine. Occupants will never paddle. Even in a breakdown, I'm the guy paddling.

 

Corley: I have run this by Kurt. He feels it's two different boats. He's probably right, but it's worth exploring here because I can only carry one boat and it needs to provide both types of service.

Waikikin: Yes, those hulls combined would be just right. Slippery, long hulls like a Tornado catamaran hull as the "lower part", then a huge knuckle/flare to sink down to when fully loaded.

Can this be done?

 

Do you like to scare your guests? A monohull with a beam much wider than the unladen load waterline will heel a considerable amount when the first or last person aboard steps near the rail. It can be un-nerving for someone not familar with the boat. To avoid that you'll need a multihull with sufficient buoyancy in the outboard hull(s).

 

Sort of like the vaka on this trimaran. See how it's a narrow, efficient hull at one waterline, but if you sunk it down with weight, it would have more and more buoyancy (as well as more and more resistance and less efficiency)?

It would be like this picture, except even more of a flare.

I am picturing a boat that has, literally, two waterlines. One for when my wife and I need to run around at higher speed and be able to hit rougher water with it and a different one for when it's fully loaded down in the harbor acting as a work horse moving 1500lbs at "no wake/5MPH" speeds.

 

Why such a relatively large outboard if efficiency is a concern?

What are your speed requirements?

USCG safe loading requirements for outboard powered boats will apply unless it is a multihull even when loaded to maximum capacity.

One solution might be a catamaran configuration; outboard hull sides near vertical, inboard hull sides with considerable flare so volume increase rapidly with immersion depth.

 

I thought you said there was a 4' beam constraint.