Plywood laminate strength

[Explorer 19TV]

I am currently working on a build and I have a question and not sure if I am asking it correctly.
If you were building a flat bottom planning hull
16’ length
7’ bottom width
12-15” sides
Desired max speed 20-30 mph
Displacement approximately 2100#

Could you use 1/4 marine ply for the hull if glassed both sides. Would use an egg crate stringer/framing system

Spans on 16” centers square. Basically creating a box. Thanks for your response.

[cape man]

1/4 " for the sides should be fine, but I would go at least 1/2" for the bottom.

[Explorer 19TV]

Thanks cape man.

[fallguy1000]

1/4 " for the sides should be fine, but I would go at least 1/2" for the bottom.

Agree

[Explorer 19TV]

Thanks guys.

[Evan_Gatehouse]

With all the support from the framing 16" spans, you can use thinner than 1/2".

If you are glassing both sides with a single layer of 12 oz biaxial you probably could get away with 3/8 quite easily.

[OneWayTraffic]

Or you could buy one of the proven Mertens plans and know that it will work. If nothing else the specifications would be a good guide.

[Explorer 19TV]

Thanks for the replies, I’ve built a few boats as well as rebuilt a few. I have a couple sets of plans and I am using that as a reference as well.

Just wanted and respect the forums opinion as I know there is a lot of valuable knowledge here.

[Explorer 19TV]

Going with the 3/8 for the bottom for sure with one to two layers 17 oz

[OneWayTraffic]

17oz on 3/8". No worries about that breaking unless you plan on dropping it off buildings.