Prout Owners Association

My Prout Escale 39 has an indentation in the bottom of the nacelle which is open to allow sea water in and out of a compartment underneath the fuel tank. There is an opening at the bottom of fuel tank compartment in which you can see water. My question is this: How far does this compartment extend? The entire length of the nacelle? Is this flow through of sea water really necessary? I assume it is to release fuel into the sea rather than flooding the boat if the fuel tank should become ruptured.
Also is there a way to access the nacelle beneath the salon? I have gotten water in there and pumped it out through the table leg hole.
Thanks in advance.