I would use marine ply or ACX and use poly
Most likely your transom and stringers are bad
May only go to the next bulkhead, may go all the way to the bow
Seacast is a 50/50 mixture of bondo and resin and you mix in chopped up bits of old boat hulls (provided in the kit)
Did one boat with seacast. Never again. 2x the cost and the same amount of work
regarding jerry can fueling - its insurance liability. a Marina with a fuel dock has huge insurance policy that nearly doubles in price if there is an issue
plus most fuel docks will suck out the honey tank if you buy fuel.
you need to read links 24, 25, 29, 2, 3, 4a, and 4b before you get excited about that suck-hole for cash and time
https://forums.iboats.com/threads/how-tos-and-other-great-information.283508/
here is link 14...
Welcome aboard
fix your fuel issue - there should be no drip
at idle one exhaust manifold will always be warmer than the other. (hint, its the higher of the two)
I worked on a yacht that spends $150,000 a day in fuel
the engines burn 13.6 gallons of jet A a second at WOT
then again, they were on engines # 39, 40, and 41 at the time
fuel is the cheap part
most people boat only 20 hours per year.
