I have the same setup as Andy - fresh water and fuel tanks starboard. I thought of building up a shelf at forward end of the port cockpit locker, but that would probably make access difficult through the two engine hatches (see previous references to older, less flexible skippers).
Be great to have better location than the bottom of that locker. Tim Sea Scout Ship 76 1986 #6254 I have a diesel inboard and the fuel tank is under the forward end of the aft starboard berth. There is an auxiliary bladder type water tank just forward of the fuel tank and then the built in primary water tank. Therefore, there is really no spare space along the starboard side. Otherwise, that might have been an interesting suggestion to use that space in that area for batteries. A friend of mine had an Ericson 27 and that is where his batteries were. Andy Dalzell C-27 #6298 Sandusky Bay
