Boat Builder Central - Builder Forums

Chessie wrote: ↑Thu Mar 04, 2021 1:35 pm Thanks everybody. That’s what I thought.

In my mind two equal canoes (or kayaks) one filled with foam, one empty: you would think the foam filled would be more buoyant and be able to handle more weight.

Only if the one without the foam is getting squeezed. if they both remain rigid, the foam plays no role.

Chessie wrote: ↑Thu Mar 04, 2021 1:35 pm In testing, I did move the battery to between my legs

I REALLY hope that's a sealed battery

To me, it's all about "messing about in boats" and seeing what works, so I applaud the experimentation, always stay safe!

Well... obviously there will be no buoyancy benefit if the cross beams are not rigid enough to hold part of the outriggers under the water, they will just sit on top. = cross beams must be rigid enough. (IF the purpose is additional flotation)
obviously any extra area under the water line will be added drag, however with the motor that is less of an issue..... (IF the purpose is additional flotation)

It is all compromises and designing to a purpose. What works well for one purpose will work poorly or not at all for another purpose. When you find a solution that works well for multiple purposes with minimal negative effects for your intended purpose, you proceed down that thought path.

Another solution would be a larger purpose built kayak capable of handling the additional load. A 2 person kayak with 1 person and motor and battery would be no issue at all.

To make it easy to understand...foam flotation only floats if your boat is trying to sink.

All makes more sense, thanks to all.

Chris

All makes more sense, thanks to all.

Chris

I don't like the idea of the side floats. The weight of them add weight and you set lower and they don't balance the front and aft problem you have. I would rather he some how move the battery more forward and not between his legs. Maybe add some lead weight. I don't know how much his motor weighs but surely not that much, I assume it is some kind of trolling motor. I know a lot of kayakers and they are very particular on how they balance their boats.

Well you take care and good luck on balancing your yak.

Tom

Here is another picture that will help with the foam intuition. These sponsons only add weight, but make the canoe very hard to tip over. A fixed sponson set below the waterline can add displacement, but only to the extent of its size less its weight. Since foam is light; it can offer some gains, but again a dreadful resistance force/drag.

I apologize if I seem to be beating a dead horse. I tried to fun it up with some pics. There is ice on the lake edges here. Falling in is deadly, especially with 8 pound boots on. The fish picture is one of my favorites. That fish was about 18#.

My amas are typically hitting the water on one side of the boat and the other side is not touching the water unless we shift weight. They also need mounting space and the middle is best. Look close and you'll see they are quite a bit above the water without 400# of crew.