That is great news!
I totally missed "the boat" with my response!
I read your question on my phone and saw "Ski King" and thought it was a glass boat..
Dude, replacing the transom on that aluminum boat shouldn't be all that bad! Just try to get all the old wood off the aluminum and drill out the old screws. Try to re-use the screw holes and not drill any new ones.
Once all traces of the old wood transom are gone, get a large piece of cardboard and build a template for your replacement board. Marine plywood is a great start and if you can, try to retain the original thickness of the transom. Depending on what your plywood thickness is, that may mean doubling it up!
I would also consider having a custom piece of aluminum fabricated to fit over the plywood, on top and covering the engine(s) mounting area.
Treat the marine plywood with Deks Oil after cutting to shape -but before installation- paying particular attention to the end grains, as that's where water will start to seep in.
Seal all the bolt holes with 5200 Marine Polyurethane sealant and you should have a solid transom!
Another thought is to go see the professionals at
www.HarborMarine.netThey will be able to point you in the right direction with regard to products and procedures for your project!
Great question and good luck!!!....