Rustybarge
Guru
What warranty? I'd never repower with a new engine(s). Secondly, the premise in this instance was to run the boat at reduced speeds/power, so the replacement engines would be in a much, much smaller package....probably fit through the hole for the stripped V12 block. If not, make the hole slightly bigger. Chopping a hole in the hull is crazy.
I've actually looked quite closely at repowering a stabilized Hatteras yachtfish or cockpit motoryacht with one mid sized turbo six...say in the 350-400 HP range... driving the two existing transmissions through a splitter gearbox (or a splitter chain drive box from Ramsey Silent Chain). The engine room in those bigger Hatts is begging for that set up. Spectacular stabilized coastal cruiser and live aboard for reasonable money. If you wanna go slow...do it in style.
I was thinking that you could leave the main engines in place as ballast and squeeze a straight 6 or 4 cylinder engine into the space between the two main engines; easy to fabricate plates to fit onto the main engine mountings.
This way you could place a chain drive to the two original gearboxes saving lots of money.....and of course the main engines could be fired up in an emergency!:lol:
The new engine could be a small 4gal/ hr/continuous to give about 7 kts.