Batteries up the bumpy end, under the bunks of a tin offshore boat...!
Are you planning on using any special type of batteries Redhunter, or just the plain lead acid marinised type? Any special precautions for this location?
You would also need some seriously sized battery cables to minimise voltage drop - long way back to the donks!.
Maybe you have a game plan already, just curious. Don't think I would like them up there, too risky!
Cheers
Brendon