A bit out of the ordinary this one. Carrying out an electrical install on a 200 year old ex warship. We have installed Rcbo protection on all local circuits on the boat. There is a 50mm 4 core swa cable going to be supplying the boat direct from a lucy box with a isolator then cutout and meter supply from the Dno on land. We are also going to be providing a Earth rod for a TT system but would the supply cable supplying to the boat require Rcd protection? Ive been referring to Marinas regs for advice but im aware its more in reference to smaller boats hooking up to a socket rather then a ex warship perminatetly docked now used as a museum. Any thoughts?