...transom/boat?

That looks like one of those military boats made by Fountain.

US MARINE I believe in New Orleans

Here's one in motion..

there is one on ebay for a lowely 200k listed with the ferraris. Too much for that in my mind.

if it could be had cheap it might be a fun project.

That's the third time it's been listed on E-Bay.
Current opening bid is 99K (not 200K) which is down from the 150K he was asking last time.
If I remember right it's located somewhere near Philadelphia.
It would be a unique boat to have, not much use except running around. Would be fun though.

Innovation builds the engines, I beleive the boat is built by US Marine.

There's a member on OSO that knows who builds them but can't say for security reasons. He may even work for the mfgr.

In the top pic, there's two large vertical brackets outboard of the drives. They have holes to mount something. Anyone have an idea as to what they're used for? I have a few other pics of HSB's and they have them too.