View Full Version : Ply thickness for small skiff

Paul H
11-19-2003, 12:01 PM
I'm thinking of scaling down the design of the 22' cabin cruiser I'm building to make a small dingy/skiff to be carried on top of the pilothouse. The cabin cruiser is a stich and glue w/ 1/2" ply on the bottom, and 3/8" on the sides.

My question is, if I scale it down to a ~12' length, to be rowed or powered by an 8 hp o/b, would 1/4" ply be sufficient? It would have stringers on the bottom, and be sheated in 10oz glass.

Bruce Hooke
11-19-2003, 12:13 PM
First, off...be careful when you scale down the design -- you may well need to increase the relative width of the skiff to keep it from getting too narrow & unstable. Other changes may be called for as well for it to work well. When you reduce the length by half you are pretty much designing a new boat and need to consider all the issues that would go into creating a good new design.

That aside, there are certainly 12' skiffs that use 1/4" plywood; I'm building one now that's 14' long and uses 1/4" plywood for the sides and bottom. A lot depends on how close together the various supporting stringers and ribs are and similar issues such as the width of the various panels. One way to approach the issue is to look for similar designs and see what thickness of plywood they use.

11-19-2003, 12:59 PM
Like Bruce says. 1/4 inch should be ok, but reducing the design and framing that much might not be.

Paul H
11-19-2003, 01:05 PM
I wouldn't be reducing the beam in 1/2. I'll be looking at similar size boats to get a feel for proper proportions. What I was basically thinking of doing was trying to get maximum yield from plywood sheets, and keep the general lines of the boat. The cruiser has 30" bottom panels, and 3" flats, for a ~66" beam at the waterline. I was thinking of dropping the bottom panels to 24" wide for a ~48" beam at the waterline. The sides would also be dropped from 32" to 24".

On Vacation
11-19-2003, 01:11 PM
So many little boat designs and plans, so little time to guess at a big change between 22 to dingy size to cabin top. Looking for a challenge? Fine. Looking for a small boat, with a particular design in mind, to fit your needs, Type in "dingy" rowing boats, "tenders" and even search this forum for the same. my .02 cents

11-21-2003, 06:23 AM
Paul, I built a 14' skiff with 1/4" ply, driven by a 15 hp outboard at speeds up to 25 mph, no problems yet.