New design, will it work?

[Thin water]

I have started a radio controlled boat making business. I have built the pictured plug out of plywood from scratch and decided that after I make the mold from it I could lay up four of the hulls without their transoms, glass them together stearn to stearn and make a set of pontoons. They are 15" wide and 72" long and 10" deep. It would yield a pontoon of 12' long. I figure I could foam fill them then apply a deck on top of each one and make a 4' x 8' deck for the top like a mini pontoon boat or set it up like the outrageously priced Craig Cat ( A plastic roto molded boat that looks like a pair of surfboards that sells for over $11,000).

Power would be kept under 9.9 hp and may be one or two electric trolling motors.

Any ideas, concerns?

JIM

[Trevlyns]

Hi!

With just the very roughest of eyeball estimates, I would say that displacement may be a problem. Given the dimensions and configuration and applying an estimated prismatic coefficient of .56, total displacement (at the sheer) would be about 140kg for the craft. Bearing in mind that you would want a waterline maybe midway of total depth, this would reduce that figure considerably.

You do your boatbuilding in the kitchen, I see. At present I have a set of frames glued and clamped on the dining room table! The missus and the cat won’t speak to me anymore…

Originally Posted by Trevlyns

Hi!

With just the very roughest of eyeball estimates, I would say that displacement may be a problem. Given the dimensions and configuration and applying an estimated prismatic coefficient of .56, total displacement (at the sheer) would be about 140kg for the craft. Bearing in mind that you would want a waterline maybe midway of total depth, this would reduce that figure considerably.

You do your boatbuilding in the kitchen, I see. At present I have a set of frames glued and clamped on the dining room table! The missus and the cat won’t speak to me anymore…

hey trev.
off topic you read sara henderson eh
you may be interested to know, i have a friend here with a station of 500sq km, or 500000 Ha
come fer a picnic, bring 4 days rations) stu

[Trevlyns]

Hey thanks for the offer Stu, just may take you up on that someday – sure makes me jealous! I basically had to limit my design to 8 meters – biggest size that would fit (diagonally) in this puny English back garden. And even then, I can only build one hull at a time (building a catamaran) – dodging the wife’s plants, washing line etc. - and will then have to assemble beams and bridgedeck elsewhere. The curse of seawater in the old veins…

Who's sara henderson? I just liked the quote and thaught I'd giver her the credit!

[Thin water]

Thanks for the reply.

I have to use the kitchen sometimes since my first shop (24 x 30') has a 16' x 8' airboat mold, chop gun 2 lathes a milling machine 2 metal shapers etc.......

I built a second shop of 20' x 30'. Now it is full currently with a 16' john boat I just made and 10 mold sets for the radio controlled boats.

My wife is not amused.

I will caculate out the displacement before actually building it and see if a third hull would be of value. I did not intend for it to be a pontoon when I made it so it is no big deal if it won't work.

JIM