7hp Farymann Diesel Marine Engine 18W + 2:1 trans NOS

Try looking at this link for a small diesel eng/trans combo, the price seems right, has a built in alternator, I don't know if I like that.
I'm sure the light bulbs are 12 volt, any RV store will sell them.
I would pull the A-4 on the hard, unless your plan is to deep six it in the ocean and call it a man made reef
Maybe this helps.