JEM Watercraft

howdy,
wanting to build a pontoon around 14ft (4267mm) in length and 6ft (1828mm) in width having 3 pontoons, i work with sheet metal all day everyday making air ducts so i figured that using .6 or .8 sheet metal rounded to 550mm dia would do the job.

the cross members would be wood and alloy and the deck will all be wood and i will not need all the nice chairs and furniture found on other pontoons best try to keep the weight down. its just a fishing boat to get around the rivers here in australia. will it be 2 heavy????

just would like to hear from some of you what you think about this Idea
will if float? will it sink what are your thoughts???? what else should i do

Well it should float long as everything is sealed up. I'm not sure how much you sheet metal weighs.

G'day Yarrick
I have seen numerous pictures in my past where various young Aussies have built canoes from sheets of corrugated iron and used them on the farm dam or the Murray river and they worked. Corro is about 0.6mm I think
Cheers Mike

The force of buoyancy is equal to the weight of water you displace. If your rig weighs 100 lbs then it will have a buoyancy of 100 lbs in other words it will displace 100 lbs of water. Battleships are made of steel. Very thick and heavy steel and they weigh a lot and they displace a lot of water. They would sink if they were heavier than the water they are displacing but since they are hollow their volume allows them to displace the water equal to the weight of the vessel therefore, they float.

alas poor Yorrick - err Yarrick

sorry mate. Welcome aboard.

I see no benifiet in the steel thing. It will float, but will rust fairly quickly and all your work will be in vain.

Why not build one from ply? and sheath it with Epaxy resin. It will last you a life time, weigh less and be stronger. - and prettier

Where in Oz are you from - roughly?

howdy all,
i live in brisbane mate,

well rochedale south , so anyway i have been looking at alot of stuff so far thinking that maybe not going so big for the
first build,

those mini pontoons look alright as a first along with the wood cause there can be alot of extra shit done on the wood ( under floor eskie = god gift to me) i have been also in the desgin stage planning what will best suite me in pontoon shapes Hex, U, round and V i will be posting some photos soon of the drawing board so you guys can help out and do some correcting for me

thanks alot for the replys, going to bunnings now to get some wood i gota start building

Yarrick,

While I've never built or paddled a pontoon boat, I have seen some that seemed to make a lot more sense to me than others.

If the pontoon is the main flotation (as with the platform boats of, say, 10' X 16') then your pontoons want to be tubular shaped with sharp entry and exit stem ends.

If, on the other hand, the pontoons are outriggers for stability, then other shapes come to mind. A sharply vee'ed shape with a lot of rocker makes sense then. If the pontoon is to be maily out of the water, and dipped only for stability , this presents as little resistance as can be gained, I'd think.

But, as I said, I have zero experience here - only instinct.

Kayak Jack
hay mate, i am still lerning my self so please anymore info you have lay it down so i can read it

I've already told you more than I know. I just think that an outrigger should be exceedingly streamlined and present as little drag as possible. It should ( I think) enter the water only incrementally, do its job, then be able to be raised back out once stability is regained.

In other words, the primary hull should be the primary thing in the water, and outriggers only in as necessary. Now, maybe that's an unrealistic view? But it's how I think of pontoon outriggers.

A pontoon boat is another matter altogether. A large platform, resting on pontoons, is a party boat. LONG on stability & utility. A fellow could fish, BBQ, sleep, eat, & live on one of these large things. Pitch a 4 man tent or sling a Hennessy Hammock there and camp out. I'd probably avoid building a campfire, though.