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boat weights due to material selection

Posted by ccarlson 
boat weights due to material selection
October 25, 2017 07:09PM
I am ready to build, but I am questioning materials in regard to weight. Specifically honeycomb side panels vs plywood sides.
#1. Can a boat be too light?
#2 What are some of the pros and cons of heavier vs. lighter boats.
#3. Do honeycomb sides panels save that much weight since they require more layers of epoxy and glass?

Thank you,
Re: boat weights due to material selection
October 25, 2017 07:31PM
I don't think a boat can be too light. This is a religious issue. Others will argue against.

However honeycomb core isn't much lighter, if at all, because of the extra glass needed. You need a lot more glass for bottom panels. For 1/4" or 3/8" plywood sides you can use just one layer of 4 to 10oz glass. That's a wide range but I've done it all and it all works.

The advantage of honeycomb core is not weight it's about not soaking up moisture if the glass skin is dinged. And dinged it will be. Side panels aren't below the water line much so it's less of a problem with side panels.
Re: boat weights due to material selection
October 26, 2017 01:48AM
What would be your lay up for plascore type sides. This is more out of curiosity. I like the idea of wood sides for aesthetic reasons. I also enjoy working with wood. I was hoping that an ultralight boat could be built using a plascore type material. Do you know of any ultralight type 3 person drift boat/skiff/pram being built?
Re: boat weights due to material selection
November 27, 2017 03:29PM
Unless you have a lot to time on your hands, I would just use 1/4 plywood on the sides. I have built 2 all plascore boats and 1 with a plascore bottom and plywood sides. It's only a guess but I doubt the plascore sides will save you 10 pounds which is basically nothing. In addition, there is the issue of sealing off the top edge of the plascore at the gunwale. If you were to round it over with a grinder (plastic dust everywhere) then glass up and over you are going to waste hours of time doing it. A 14 foot HD with a honeycomb bottom with plenty of glass and plywood sides will have a final weight I think you find is totally acceptable and lighter then any commercial factory boat you will find.
Re: boat weights due to material selection
December 04, 2017 07:34PM
The plans I have call for 3/8 ply sides. I would like something virtually maintenance free. How about a corecell/ foam core material. Should be light weight, and would not require filling cells?
Re: boat weights due to material selection
December 04, 2017 08:42PM
Sure. I've built plywood core (covered with glass both sides), end grain balsa core and Plascore. I've never done a foam core layup, except for seat tops anyway.

You don't need much maintenance on 1/4" or 3/8" plywood sides, if and only if they are covered in glass.

What foam and honeycomb cores are really good for is the bottom panel.
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