I have no blackwater holding tank on my boat (an old English boat with just a sea head) and have a large steel freshwater tank under the vberth exactly where I'd install a blackwater tank if the other tank wasn't already there.
I'm thinking about just using that steel tank for the blackwater holding tank, and installing two new collapsible freshwater tanks in the bilge (there are two perfect spots on each side of the for them).
The main benefit of having the blackwater holding tank in the vberth is that it would be trivial to configure a gravity drain to the current sea head thruhull. If I put a holding tank in the bilge, I'd need to always pump it out when offshore since it would be below the water line.
My only concern is whether the salt in the seawater will cause the steel holding tank to rust out (since the head flushes with seawater, not fresh). Would that be a problem?
I'm thinking about just using that steel tank for the blackwater holding tank, and installing two new collapsible freshwater tanks in the bilge (there are two perfect spots on each side of the for them).
The main benefit of having the blackwater holding tank in the vberth is that it would be trivial to configure a gravity drain to the current sea head thruhull. If I put a holding tank in the bilge, I'd need to always pump it out when offshore since it would be below the water line.
My only concern is whether the salt in the seawater will cause the steel holding tank to rust out (since the head flushes with seawater, not fresh). Would that be a problem?