JEM Watercraft

For my Merrimac build,
would 2x2 thwarts need cleats under them?
Or would the cross section size hold enough filled epoxy to be enough?
(Thwart placement will be tight up under gunwales).
Thanks.

This process works well. You can added some cleats for extra security.

22. Install Thwarts
• Install 1-2 thwarts. For easy recreational paddling, 1 is fine. For camping and cartopping,
install 2.
• Construct the thwarts to the same dimensions as the rub rails. Or make from one solid
piece of hardwood like ash. Don’t forget to coat it with epoxy.
• Secure thwart to hull with glue and screws driven from the hull exterior. The screw shaft
should be driven at least 1” (2.54 cm) into the thwart. So at least a 2” (5 cm) long screw
is required. Drywall screws work well. Stainless steel wood screws would be optimum.
3/8” (9 mm) thread diameter.
• Glue the thwart into place first. Fillet and tape to the hull or extra strength.
• Drill a pilot hole using a 1/8” (3 mm) drill bit.
• Drive the screw. Install it a little deeper into the hull skin and cover with filleting material
to hide and seal the head of the screw. Sand smooth.

Thanks Matt.
So blessed to be able to build a boat well without being an engineer/designer,
we just have to get (and follow) the advice of the engineer/designer (you )