seat wood cracking help

so i finally took the boat out and now the wood i put on the benches to then screw my seat bases has started cracking some,no major cracks but its cracking ,whats best fix? they were exterior plywood pieces that were thompsons water sealed then just spray can painted ,can i put paint on again to help seal the cracks or do i have to start over on the seats? thanks

Did you pre-drill the holes? If not, that is why it cracked.
As far as what to do, depends on how bad the cracks are. If they effect the seats structurely, replace. If not, maybe put in some waterproof wood putty & then repaint.
Also, not sure how well can spray paint will protect the wood anyway. A coat of primer followed by a couple coats of good exterior or marine paint is the way to go.
Thompsons is petroleum based, it can actually prevent paint from penetrating the wood.

Did you use a backing plate on the bottom of the wood for your seat mounts?