Seafari batteries forward advice?

[Bushwacker]

I've seen a Seafari with a couple Group 27 batteries in the compartment up under the center hatch below the bunks. They were mounted on a shelf mounted between the stringers and would need to be well secured due to the G loads they'll see up there when you get into rough seas. I believe a Group 27 battery will just fit through that hatch, but I'd make sure it's a marine battery with a built-in lifting strap because otherwise it'll be a bear to lift in and out of that hatch! You would probably have to use larger cables to avoid excessive voltage drop due to a total cable run of ~ 35' or so from batteries to engine. (Have to use total length of both + & - cables when using voltage drop tables!) You could run the cables under the bunks back to the bulkhead, where you could mount + and - buss bars behind the instrument panel. I'd be inclined to mount the battery switch on the aft side of the bulkhead, maybe below the helm, where it's easy to access. (Mounting a battery switch under a hatch is a bad idea. A friend of mine lost a 36' Viking sportfish due to that! His boat developed an electrical fire shortly after he left the inlet on his way to the Bahamas, and his automatic Halon system went off and killed the fire and the twin diesel engines, but when he opened the engine hatch to turn off the battery switch, the fire re-ignited! Boat burned to the waterline and sank just a couple miles outside the inlet! Fortunately the black smoke attracted lots of boats so he and his family were able to get off the boat safely!)