Boat Building Forum

Find advice on all aspects of building your own kayak, canoe or any lightweight boats

Re: Strip: Glass warp & weft direction
By:Ancient kayaker
Date: 5/1/2014, 11:40 pm
In Response To: Strip: Glass warp & weft direction (Paul Hansen)

Glass is so much stiffer than wood that it will react most of the forces involved in a boat on the water. The wood is just along for the ride mostly, fore-and-aft as well as athwartships. The wood's jobs are to look pretty and keep the glass layers spaced apart. It is simplistic to assume most of the forces are tension in the bottom and compression in the top.

Buckling resistance varies as the 4th power of thickness so in a thin-planked vessel compression force is handled mostly by the gunnels which are the thickest part of the structure and therefore best able to resist compressive loads without buckling.

But that's only part of the story. In a small boat like a kayak the paddler's weight generates tensile forces around the circumference of the hull up to the gunnels.

Concentrated loads on the bottom such as the paddler are reacted through a relatively narrow band of glass up to the gunnels , so I suspect that using a glass weak in this direction could lead to failure of the glass. My guess would be on the inside at the turn of the bilges. Now in a Canadian style canoe where the seats are hung from the gunnels, you might get away with it but I would add an extra bottom layer with longitudinal warp.

Messages In This Thread

Strip: Glass warp & weft direction
Paul Hansen -- 5/1/2014, 1:19 am
Re: Strip: Glass warp & weft direction
John Kroeze -- 5/1/2014, 3:35 am
Re: Strip: Glass warp & weft direction
Yoshi -- 5/1/2014, 10:32 am
Re: Strip: Glass warp & weft direction
Marc Upchurch -- 5/1/2014, 1:05 pm
Re: Strip: Glass warp & weft direction
Ancient kayaker -- 5/1/2014, 11:40 pm
Re: Strip: Glass warp & weft direction
Sam McFadden -- 5/2/2014, 11:59 am
Re: Strip: Glass warp & weft direction
Paul Hansen -- 5/2/2014, 12:53 pm
Re: Strip: Glass warp & weft direction
Sam McFadden -- 5/3/2014, 10:13 pm