I used the Rustoleum paint in " hunter green" last summer on my 12' jon boat. Used both brush on and spray for first coat to get everything covered. After that dried, went over as much as pissible with a paint roller and sprsy cans to get a more uniform covering. This stuff works great and easy to find in brushon and spray cans.
If you have any leaky spots, try a product call clear coating or clear sealer, this stuff is sold at Home Depot and Tractor supply in my area, also availiable online, comes in a light blue colored can. This stuff is an excellent sealer, made for shingle roofs and metal siding, I sealed my jon boat over 5 years back with no leaks to this day. This stuff is brush on type of material.