Bit&Kontell; Outrigger Pocket Cruiser

 
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24 April 2014 13:11
 

I saw this design by French designer Yann Quenet and thought it would be of interest here.

Bit&Kontell; 5.50: “Not really a cat or a tri or a proa, cruise freely combining storage volumes and light, and space for a kayak or various boards.”

He’s put the outrigger ama to good use, with the daggerboard and mizzen mounted there, as well as providing a big hatch and enough volume to carry a significant amount of stores. We also like the simple standing lug rig, and the kayak as “safety ama”. Not much info beyond the pics, what do you guys think?

See more images here.

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24 April 2014 18:24
 
Editor - 24 April 2014 01:11 PM

, what do you guys think?

In no particular order.

It’s a lot of stuff in an 18’ package.

Kayak is nice.

Weights going to be a challenge.

Bill S. is probably going to look real hard at this one.

Daggerboard seems a little aft.

A lot to like, getting two fore and aft berths in 18’ a real accomplishment, couldn’t do that in a leaner proa I think.

Cheers,
Skip

 
Bill S.
 
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Bill S.
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25 April 2014 13:42
 
Skip - 24 April 2014 06:24 PM

Bill S. is probably going to look real hard at this one.

The real magic in proas is high speed using minimal materials (performance at minimal cost).  The speed is obtained by narrow, light, long vaka hull with good righting moment resulting from a wide platform and low drag ama.  Any deviation from this formula will result in a slower boat and often more expensive boat.  Pacific proas have further magic in the structural efficiency of the windward ama and tensioned structure between the mast, the akas and the stays.  Lifting the ama as righting moment is needed (and reducing drag as it lifts) is an important part of the magic. 

The Bit&Kontell concept does manage to pack a lot in a small package, but I think it steps a little too far outside the formula above.  I don’t see this design as particularly fast or minimal.  I would anticipate the B&K to be bass drum noisy at anchor and I expect it would pound mercilessly in any chop.  Sharpies deal with pounding by sailing at a good level of heel burying a chine, but this boat would by design try to stay flat. 

Just like Detroit historically solved slow with cubic inches and massive gasoline flow, proas solve slow with prismatic efficiency and long waterline length.  Efficient and long waterline hulls mean 12:1 L/B (or much better) - and that unavoidably defines accommodations.  There ain’t no such thing as a free lunch (apologies to the late Robert A. Heinlein).

I’m interested in how far I can push a proa build to stay “magical” and still handle one to two people in dry and warm bunks at the end of the day.  The B&K concept meets the accommodation criteria but the short waterline, sub-par L/B ratio and the draggy ama look to make the boat a bit too far outside the sweet spot for me.

It is nice to see other people’s thoughts.  I bet the B&K design would blow away West Wight Potters, Pocketships and Nancy’s Chinas.  I don’t want to be the fastest turtle in the pond limited to 15-20k expeditions from the dock on weekends.


Bill S. in Ottawa

 
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25 April 2014 14:36
 

I think Evergreen is a better answer to that question.

 
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25 April 2014 21:09
 

Just like Detroit historically solved slow with cubic inches and massive gasoline flow, proas solve slow with prismatic efficiency and long waterline length.  Efficient and long waterline hulls mean 12:1 L/B (or much better) - and that unavoidably defines accommodations.  There ain’t no such thing as a free lunch (apologies to the late Robert A. Heinlein).

So go long or go home? I can agree with that, until I come down to the reality of my 20’ garage. 😉 If the question is how short can you go and still have some multihull canoe virtues, then I guess Chris is right, cats win that one. This one’s almost a catamaran, but not quite. A fun hybrid.

Though damn, those fat, flat bottoms do not make my world go ‘round.

 
 
Bill S.
 
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26 April 2014 09:21
 
Editor - 25 April 2014 09:09 PM

So go long or go home? I can agree with that, until I come down to the reality of my 20’ garage. 😉 If the question is how short can you go and still have some multihull canoe virtues, then I guess Chris is right, cats win that one. This one’s almost a catamaran, but not quite. A fun hybrid.

Build Space:

Therein lies the problem.  My current approach is to build the boat in three 8’ sections - with temporary construction bulkheads in place till the three units are assembled together.  Each of the sections can be 90% finished separately, leaving butt block scarfing, taping and seam fairing last.

Virtue of waterline length:

Evergreen looks like the real winner of the competition (for me at least).  It look like it is about half the build effort of the winning Marples/Brown tri, with comparable performance, similar trailer ability and lower cost.  How could it not win?  Why do people always undervalue money and build effort as major criteria?  Chris IS right on this one - in a 20’ proa, you just can’t get the job done as well as a cat.  I’m wondering how much can be accomplished in a 24/25’ proa?  It certainly would not have as much usable space as Evergreen, but I’d be going in with eyes open.


Bill S . in Ottawa

 

 

 
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27 April 2014 12:06
 
Bill S. - 26 April 2014 09:21 AM

My current approach is to build the boat in three 8’ sections - with temporary construction bulkheads in place till the three units are assembled together.  Each of the sections can be 90% finished separately, leaving butt block scarfing, taping and seam fairing last.

This makes a lot of sense, but if it’s going to be a permanent connection, why not build it in two pieces rather than 3? The pair are identical, could even be built simultaneously (with the non-current one hoisted overhead—a stacked workshop!) Plus as there’s only one final joint, the inevitable weight gain in a joined boat is minimized.

The longer pieces will also encourage you to go longer on the ama; ama should be a minimum of 16’ on this 24’er, IMO.

Then again, mention of multi-piece amas reminds me of a “clever” concept I played with, years ago. Back to 3-pieces/hull; build 4 identical bow pieces, each 7’ long. Build one center piece 10’ long (which becomes the vaka with 2 bows glued on) and one center piece 2’ long (which becomes the ama with 2 bows glued on. Oh, and there’s the justification for you building in 3, not 2; pieces even if just for the vaka:  You can do pretty much the entire livable space, plus aka mounts, all in the center section. The bows are just minimal shells.

Dave

 
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28 April 2014 06:47
 

Taking a nominal 24’ hull seems like the natural breakdowns for same conceived in plywood would be.

8’ - 8’ -8’
12’-12’
4’-16’-4’

The last one ‘kinda’ appeals to me, the latest iteration of Nomad is 16’ foot of berth bulkhead to foot of berth bulkhead.

Cheers,
Skip

 
red cedar
 
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14 May 2014 11:34
 

I’m very curious,,,
What about this split (nearly bi-plane) rig configuration?
Any opinions or experiences with additional sails mounted on the ama?

 
Bill S.
 
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14 May 2014 12:17
 
red cedar - 14 May 2014 11:34 AM

I’m very curious,,,
What about this split (nearly bi-plane) rig configuration?
Any opinions or experiences with additional sails mounted on the ama?

Opinion? Yes.  Experience in the type? No.

The rig as drawn will have a “good” tack and a “bad “tack”.  Unlike bi-plane rigs (Schionning, Evergreen etc.) or more conventional yawl/ketch/schooner rigs, on one upwind tack this rig will place the mizzen directly in the turbulent wind shadow of the main, making it questionably able to contribute to forward drive.

My other possible issue is that this design already has a large and draggy ama, with far more size and structure than most minimalist proas - now there is mast support structure added to the ama for the unstayed mizzen.

In my opinion, I’d much rather build a proper bi-plane cat like Evergreen or a proper proa like Nomad if I were committing the dollars and hours.

Every design is the net sum of it’s choices and compromises.  I’m not certain I would have arrived at this particular conclusion given my design brief.  It probably does check off all the boxes for other people.


Bill in Ottawa

 
red cedar
 
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14 May 2014 22:05
 

Yeah Bill,
that’s a good point about upwind turbulence on the ‘bad’ tack.
and i wonder at why the large size of the ama (even for an outrigger), considering that low aspect lug rig is not going to generate a high righting moment?