Boat Building Forum

Find advice on all aspects of building your own kayak, canoe or any lightweight boats

Re: Catmaran kayak? I have one --- almost
By:Carl Delo
Date: 5/27/2008, 6:15 pm
In Response To: Re: Catmaran kayak? I have one --- almost (Bill Hamm)

: Hi Carl,

: Very interesting, you're further along than I am. The one I'm thinking of is
: quite a bit narrower though, around 21" beam. Basically a surfski
: split in half, though the hulls do have to be much deeper to compensate
: for the reduction in displacement. Definately will need a rudder, will
: look silly but with the hulls so close together there's only a need for
: one rudder from the bottom (or stern) of one hull.

: I would though suggest that making the individual hulls more full at the bows
: should help them not bury as much in waves. Very narrow hulls tend to do
: that. There's a term for the relative fullness of the hulls that right now
: escapes me (senior moment ).

: Will be looking forward to seeing your progress. Hey I can wait and learn
: from someone else mistakes (for once ).

: Bill H.

What, mistakes? Me? Heaven forfend...

But seriously, Re: the overall beam, one of my design criteria is to allow a swimmer to lounge around between the hulls in the stern to rest, so I am working with a 12-16" spacing - I think the 24" overall beam is optimistic, it will probably be more. The greater beam may be offset by the higher seating position of the paddler, allowing a higher paddling angle even though the beam is wide. I will play around with crossbars of various lengths to see what effect it has. A speedy version could have very narrow separation. I think the boat would lend itself well to a sailing rig with greater hull separation. I've made some sketches of a rowing cockpit (similar to a Skimmer Boat), which could be made quite narrow. Hey, if the drag is low enough, I could see putting hydrofoils between the hulls below the waterline - I have plenty of potential test-pilots on crew here at school - that would be a lot of fun.

Re: the bows, I do have them quite narrow at the moment to give a very fine Swede-form shape - the half-angle of entry is only 3 degrees which does not increase along the hull. To counter burying, I plan to use a NACA foil as the front crosspiece similar to some lifeguard skis (or whatever they're called). On the model it's just a flat plank at a guessed angle - I'll make the prototype anti-pearling plane adjustable hopefully and see how (if) it works. I may increase the flare above the waterline in the bow just to be on the safe side.

If you have any other thoughts about this design, by all means I'd love to hear them. I showed the model to a bona-fide, working naval arch and he didn't laugh, gave me a couple of ideas and told me about the original Sea Sled, so I take that as encouragement from a pro. I have a big fear that the boat will be very susceptible to being bullied about by the wind, but am going to proceed anyway.

Messages In This Thread

Seeking: catmaran kayak?
Bill Hamm -- 5/18/2008, 1:26 am
Re: Seeking: catmaran kayak?
Bill Hamm -- 5/21/2008, 1:43 am
Re: Seeking: catmaran kayak?
Mike Savage -- 5/21/2008, 6:35 am
Re: Seeking: catmaran kayak?
Bill Hamm -- 5/22/2008, 1:25 am
Catmaran kayak? I have one --- almost *LINK*
Carl Delo -- 5/27/2008, 1:30 am
Re: Catmaran kayak? I have one --- almost
Chris Ostlind -- 5/29/2008, 9:11 am
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/30/2008, 1:18 pm
Re: Catmaran kayak? I have one --- almost
Carl Delo -- 5/30/2008, 10:23 pm
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 6/1/2008, 2:54 pm
Re: Catmaran kayak? I have one --- almost
Carl Delo -- 6/1/2008, 11:41 pm
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 6/2/2008, 1:53 am
Re: Catmaran kayak? I have one --- almost *LINK*
Carl Delo -- 6/2/2008, 9:36 am
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 6/2/2008, 3:26 pm
Re: Catmaran kayak? I have one --- almost
Carl Delo -- 6/2/2008, 5:43 pm
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 6/2/2008, 5:54 pm
Re: Catmaran kayak? I have one --- almost
Mike Savage -- 6/3/2008, 3:26 pm
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 6/3/2008, 5:55 pm
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 6/3/2008, 3:51 pm
Re: Catmaran kayak? I have one --- almost
Carl Delo -- 6/2/2008, 6:43 pm
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 6/3/2008, 1:58 am
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 6/2/2008, 1:45 am
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/30/2008, 11:08 pm
Re: Catmaran kayak? I have one --- almost
Carl Delo -- 5/30/2008, 11:23 am
Re: Catmaran kayak? I have one --- almost------Web
Dan Caouette (CSFW)------WebKitFormBoundaryqtsCtZA -- 5/30/2008, 11:57 am
Re: Catmaran kayak? Floatation
Carl Delo -- 5/30/2008, 10:28 pm
Re: Catmaran kayak? I have one --- almost------Web
Bill Hamm -- 5/30/2008, 1:21 pm
Re: Catmaran kayak? I have one --- almost *LINK*
Dan Caouette (CSFW) -- 5/29/2008, 1:55 pm
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/30/2008, 12:02 am
Just Curious.
John Monroe -- 5/29/2008, 4:38 am
Re: Just Curious.
Bill Hamm -- 5/30/2008, 10:46 am
Re: Just Curious.
Carl Delo -- 5/30/2008, 11:32 am
Re: Just Curious.
Bill Hamm -- 5/30/2008, 1:24 pm
Re: Just Curious.
Bill Hamm -- 5/30/2008, 1:08 pm
Re: Just Curious.
Carl Delo -- 5/30/2008, 10:48 pm
Re: Just Curious.
Bill Hamm -- 5/30/2008, 11:06 pm
Re: Just Curious.
Carl Delo -- 5/30/2008, 11:45 pm
Re: Just Curious.
Bill Hamm -- 5/31/2008, 9:24 am
Re: Just Curious.
Mike Savage -- 5/29/2008, 7:09 am
Re: Just Curious.
Bill Hamm -- 5/30/2008, 10:37 am
Re: Just Curious.
Mike Savage -- 5/30/2008, 2:53 pm
Re: Just Curious.
John Monroe -- 5/30/2008, 5:26 am
Re: Just Curious.
Mike Savage -- 5/30/2008, 6:37 am
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/28/2008, 1:43 am
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/27/2008, 5:37 pm
Re: Catmaran kayak? I have one --- almost *Pic*
Carl Delo -- 5/27/2008, 11:55 pm
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/28/2008, 1:43 pm
Re: Catmaran kayak? I have one --- almost
Carl Delo -- 5/29/2008, 12:28 am
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/28/2008, 1:51 am
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/27/2008, 5:27 pm
Re: Catmaran kayak? I have one --- almost
Carl Delo -- 5/27/2008, 6:15 pm
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/28/2008, 1:47 am
Re: Catmaran kayak? I have one --- almost
Bill Hamm -- 5/27/2008, 6:32 pm
Re: Catmaran kayak? I have one --- almost
Mike Savage -- 5/27/2008, 7:04 am
Re: Catmaran kayak? I have one --- almost
Carl Delo -- 5/27/2008, 12:03 pm
Re: Seeking: catmaran kayak?
Scott Shurlow -- 5/20/2008, 6:36 am
Re: Seeking: catmaran kayak?
Bill Hamm -- 5/21/2008, 1:22 am
Re: Seeking: catmaran kayak? *Pic*
Tom Yost -- 5/18/2008, 8:05 pm
Re: Seeking: catmaran kayak?
Bill Hamm -- 5/19/2008, 1:28 am
Re: Seeking: catmaran kayak? *Pic*
Tom Yost -- 5/19/2008, 2:02 am
Re: Seeking: catmaran kayak?
Bill Hamm -- 5/20/2008, 1:21 am
Re: Seeking: catmaran kayak? *Pic*
Tom Yost -- 5/20/2008, 2:35 pm
Re: Seeking: catmaran kayak?
Randy Ricchi -- 5/19/2008, 9:34 pm
Re: Seeking: catmaran kayak?
Tom Yost -- 5/20/2008, 2:26 pm
Re: Seeking: catmaran kayak? *Pic*
John Monroe -- 5/18/2008, 4:46 am
Re: Seeking: catmaran kayak?
Bill Hamm -- 5/19/2008, 1:26 am