need help in building a small catamaran

here are some free plans for a plywood cat, easy to build from local materials. Not a bad design either, even if a bit old.

http://www.svensons.com/boat/?p=SailBoats/Hobby_Kat

 

sea derby



Hm... Reminds me of this:



You know what would be awesome? If they had a show where you could sit in bleachers eating hot dogs and nachos and watch a bunch of boats like that doing wheelies and crushing smaller boats by running over them. And then a big crane barge would come out with a crane attachment that looked like the neck and head of a plesiosaurus which would pick up the crushed boats and completely demolish them. How cool would that be?

Oh! And a demolition derby for pontoon boats! I would so pay to see that.

 

By the way, there is a truck version of this too:



But it is still in the modeling phase:

 

dave,
I'm wondering about you man!
would love to see what's in you backyard and garage though!

 

Canoe Catamaran ?

I think, this is an easy way to get a small catamaran and to give it up and go back to two canoes without too much risk when you don`t like it.





http://www.boatdesign.net/forums/boat-design/canoe-catamaran-20583.html

 

this looks like a good idea.
do you know how to tie or connect the two canoes in a good an efficient way that would be easy and quick to untie? any ideas?
thanks

 

Connections

Yoram, it all depends on the canoes you have. Canoes have to be light and as a result their wall are thin. Thus you will have to spread the loads. May be you reinforce the walls with glass and epoxy when you own a glass fiber canoe.
Sometimes it seems to be useful to allow a bit of flexibility.

In one case I have made J-hooks in another I laminated clamps from glass, carbon fibers and kevlar. If you have no idea, please have a look at this: http://www.sailboatstogo.com/catalog/CANOE_RIG/5064

 

would it be enough to build the canoe from 4 mm plywood? (in stitch and glue system) or should i coat it with fiberglass too?

 

Yeah. I don't just think outside the box, I think outside the whole U Haul.

 

Canoebuilding

I have built one canoe (14ft, 17kg) of 4mm Ply (tortured) and needed to reinforce all parts where I have to stand, walk and sit. To avoid abrasion the bottom has to be protected with glass and epoxy.

If you have never built a canoe before, three books might help you: "Building Sweet Dream" of Marc F. Pettingill; "Building The Six-Hour Canoe" by Mike O`Brian et alii and "Featherweight Boatbuilding" by "Mac" McCarthy. You might also look for plans and or books at duckworksmagazin.com. A good plan is half the boat and avoids spilling money.

http://www.duckworksbbs.com/plans.htm

http://www.duckworksbbs.com/plans/storer/qce/index.htm

http://www.boatplans.dk/boat_plans.asp?id=24

http://www.boatplans.dk/boats.asp?BType=canoes

 

thanks for the info. when you write that you have reinforced some parts in your canoe, how did you do that and still kept it 17 Kg?
if i coat the whole canoe from outside with fiberglass, how much weight would it add? how much does one layer of fiberglass weight for Square meter? when you write "4mm Ply (tortured)", what does it mean tortured plywood? do you stick pins under its fingernails?;-)

 

It will never talk.....Tortured ply construction has the plywood bent in 2 directions. 2 panels are joined on a keel profile and the sides are bent in a cylindrical curve as the stem and stern are fastened adding a curve in the for and aft direction. A outside deck jig is put over the sheer to determine and hold the shape while building.The Gougeon book on boat construction has building and designing information for this fast, light build technique. A second layer can be added on the inside in places as well as framing etc..to reinforce areas. Large boats can be built this way, the Gougeons are still winning races with a trimaran they built in the 1970's.

 

ha ha ha, of course it would never talk, it was made in china. they know how to keep a secret there. thanks for your answer. do you know how much fiberglass weight for one square meter? and is 4 MM plywood and one layer of fiberglass strong enough? (i do not know how one measure strength of a boat so i do not know by what standards). it is not meant to cross the Atlantic with.

 

Hi Yoram, to keep boats light is a secret. If you take a 450g strand mat with resin you add nearly 1kg (avoid it if you can) per square meter. Reinforce the boat only in aereas where it is absolutely necessary. That is where you use to step into your Canoe.

I`ve found some nice pics for you:http://www.duckworksmagazine.com/02/projects/knudsen/index.htm



If you want to torture your ply please try to google the "Mocassin Kit" which is a good start into torturing.

 

Fiberglass with resin weighs about 96lbs a cubic foot. A cubic foot of fir weighs in at 36lbs so use that stuff sparingly!