Whaleback Proa

 
skyl4rk
 
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skyl4rk
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30 April 2013 02:50
 

I have been documenting my proa boatbuilding project with video, take a look:

https://plus.google.com/u/0/communities/104991655894056055635

 
Johannes
 
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Johannes
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30 April 2013 09:28
 

Nice progress on your proa (? I believe it is going to be a tacker, not a shunter?).
I think it will sail upwind really good. Keep the chinerunners, they help the hull to climb to windward a lot. Chinerunners really work great. I’m very impressed by them. They are only one small part of a whole concept, but in the right circumstances the do the trick. The damp pitching and all other unwanted motion too. Matt Layden is a genius!!!

Please tell us more about your Whaleback Proa!

Cheers,
Johannes

 
 
skyl4rk
 
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skyl4rk
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30 April 2013 09:41
 

I am hoping that the chine runners together with the deep vee outrigger hull will make a leeboard unnecessary.  Although I am ready to install a leeboard if it needs one.  It is a tacker.

The Whaleback was designed as a sharpie with an eye on the Paradox and many sailing canoe designs from the late 1800’s.  I wanted a boat that could be used in cold water and cold weather.  Unfortunately, I designed it too narrow and I was thinking about getting rid of it due to it being too tender.  Then I learned about proas and wanted to experiment by making it an outrigger canoe.

The original goal was to create a backpacker’s sailboat, a boat that one could drop one’s pack, sleeping pad and bag into and voyage away.  At this point, the boat will likely be used as a motorsailer on Lake Michigan, fishing for salmon with unstayed masts and a small set of lugsails for use when the wind is right.  I may do some camp cruising, depending on how the boat performs.

 
Johannes
 
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Johannes
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02 May 2013 02:25
 

I am hoping that the chine runners together with the deep vee outrigger hull will make a leeboard unnecessary

I believe the chinerunners and sharpie-hull with have enough lateral resistance for sailing upwind. Remember that a deep-V outrigger will excert a lot of bending and twisting forces on the crossbeams and attachments points, especially when sailing through waves. I don’t rely on the outrigger for lateral resistance in my proa-models. I have discovered that a skinny barge or sharpie hull has a lot of lateral resistance. It is actually quite laborious to pull my small 4,5 feet model sideways through the water. After 2 hours of sailing it out and pulling it back repetedly my arm was really sore.

The power of a 0,4 m2 crab claw sail and the sharp chines is impressive.
I believe your sharpie-outrigger-tacker will sail really good. Not multihull fast, but since it is very slender for being a monohull it will rutinly sail above theoretical hullspeed.

Cheers,
Johannes

 
 
TINK
 
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TINK
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02 May 2013 12:13
 
johannes - 02 May 2013 02:25 AM

I believe the chinerunners and sharpie-hull with have enough lateral resistance for sailing upwind.

I have always liked the idea of chinerunners but have a fear that unless the craft is moving with an even keel they will end causing a lot of drag. If the hull is pitched bow down surely the chine runner will present some strange negitive angle to the water flow. I am not being negitive just curious for the views wiser men than me.

Tink

 
 
skyl4rk
 
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skyl4rk
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02 May 2013 12:30
 

The chine runners are intended to work on a monohull where the boat heels, giving it an underwater shape of a vee hull, and the chine runner acts as a long keel at that point.  There is probably more going on but that is a simple explanation. 

I don’t recommend chine runners on a multihull, but I don’t intend to remove them from my boat.  Who knows, they may help.  There will be more drag, no escaping that.

 
skyl4rk
 
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skyl4rk
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03 May 2013 16:59
 

https://www.youtube.com/watch?v=xM8TDpmzawU

Anybody have any comments on the risers and lashing points for the outrigger float?

I have to decide whether I can make them work so I can start epoxying them down.

 
petermirow
 
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petermirow
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04 May 2013 04:29
 

Hi Paul,
interesting project. And you seem to be launching pretty soon. Congratulations!
You ask about the risers on the outrigger. My advice would be to reinforce them. Think of it similar than reefing. If you thought you maybe should do it, then it is time to do it…. 😊

Anyhow, it will not add too much weight, nor give much trouble to do it. And it something brakes there,... it will be a real nuisance. Even if your boat will probably stay upright, even without the outrigger, if you let your sails go.

Are the risers bonded to the structure of the outrigger? Or just to the deck? As Johannes has pointed out, the deep V hull will exert quite a deal of lateral and twisting forces. Therefore a sound structure is required to hold the thing together.

All the best for your launching!

Cheers,

Peter

 
skyl4rk
 
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skyl4rk
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04 May 2013 10:56
TINK
 
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TINK
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04 May 2013 12:12
 

Love the storage of the white canoe? On the gable end

TINK

 
 
skyl4rk
 
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skyl4rk
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05 May 2013 07:39
 

http://youtu.be/blIqpaENTXg

@peter

I hope to launch this year, if not, then the next…

I am a slow builder with not enough free time

 
petermirow
 
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petermirow
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05 May 2013 09:27
 

Hi Paul,

I know how it is.
I’ve been building for 5 years now. Also hope to launch this year.
Cheers,

Peter

 
skyl4rk
 
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skyl4rk
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08 May 2013 16:32
skyl4rk
 
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skyl4rk
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17 May 2013 03:06
tdem
 
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tdem
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17 May 2013 03:53
 

Looks like a simple and functional system. I’m a bit worried about how the risers are bonded to the hull. Are they mechanically fastened into some structural pieces anywhere?

Basically, supposing the top layer of ply delaminates, will this thing still be solid?

I like the overall vibe of this project, and nice job on the videos too!

-Thomas

 
 
skyl4rk
 
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skyl4rk
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17 May 2013 07:28
 

The most important connection is between the riser and the glass tape joining the deck and hull side.  That is the element that carries the most load in stitch and glue construction.

Here is a video on reinforcement that connects the riser to the hull to deck tape.

https://www.youtube.com/watch?v=QoWnkHf-qbo

It is all epoxy and glass, there are no fasteners connecting the riser to the outrigger hull.  There is not a lot of meat in the hull to screw it down to, it is 1/4” plywood with 1-1/2” x 1-1/2” crossbeams.  I could have put a few well placed screws into the crossbeam but am relying on the glass and epoxy.

I think it is wise to be very critical of riser construction.  In the future I will build curved outrigger booms to attach close to the deck of the outrigger hull.