Hull thickness

[jadranko]

What is designed bottom, side and transome thickness of a hull ?

[Brian.Dixon]

Bottom panels and chine flats are 3/4" thick, the bow area being formed from two layers of 3/8" ply.  The bottom only needs to be 5/8" thick, but it's hard to find 5/8" plywood, so I rounded up to 3/4" instead.  The weight difference is minimal.

Side panels are made from 3/8" thick plywood.

Transom thickness is 2-1/4" thick in the motor mount area and 2" thick below the motor mount area.  For the stern drive option where the transom does not have an outboard cutout, the entire transom is 2" thick.

Brian

[jadranko]

Bow is made of two layers couse of easier bending or there is some other reasons ?

[jadranko]

To add additional strength could I made whole hull from 4 layers of 1/5" (sides 2 layers) ply and between each layer put one thin layer of kevlar. Why to construct like that, first I will made thin 1/5" complete hull and then add additional layers but kevlar will cover all parts of hull together bottom, chine, side. And will be better then vacuum bagging couse I will screw layers until epoxy cure and then remove screws.

What you think about that ?

I check temperature data in my area, it never falls below 5 C (41 F), so there is no hazard of delamination.

[Brian.Dixon]

Bow is made of two layers couse of easier bending or there is some other reasons ?

Absolutely.  Bending 3/4" plywood over the bow would be very difficult while bending 3/8" plywood over the bow is easy.

Brian

[Brian.Dixon]

To add additional strength could I made whole hull from 4 layers of 1/5" (sides 2 layers) ply and between each layer put one thin layer of kevlar. Why to construct like that, first I will made thin 1/5" complete hull and then add additional layers but kevlar will cover all parts of hull together bottom, chine, side. And will be better then vacuum bagging couse I will screw layers until epoxy cure and then remove screws.

What you think about that ?

I check temperature data in my area, it never falls below 5 C (41 F), so there is no hazard of delamination.

My first thought was "overkill" since the boat is very strong as-is, and you don't need all that kevlar in order to prevent puncturing.  I think that by the time you were finished layering all those layers on, that you'd be tired of all the work and all those screw holes that had to be fixed each time.  Try my methods and I think you'll like them.  If you want increased puncture resistance, add a second layer of 10-oz woven glass cloth to the outside bottom panels and a single 5-oz layer of kevlar on the interior face of the bottom panels ...while they are still flat, e.g. pre-assembly, and you shouldn't have difficulty.

Brian