do you still have the lawnmower if you took the engin of of an industrial lawnmower there should be some good peices you could use of of it...
why put the mooring blocks on the boat at all just make a simple pontoon raft out of steel pipe or barrels much safer to use an unmanned platform...
weren't they building a giant luxury liner with a airstrip on top of it think its being built now
how bout a self righting lifeboat design put your bateries on a gimbal mount in the center and your solar array on the top deck lots of surface...