Strong odor and sewage in the hull

[Bpoist]

I recently bought a 1994 280 Express. I was going over the boat and noticed a strong smell when I lifted the mid cabin floor access. I could see a small amount of sewage in the bottom of the hull. I put a hose and cleaner in there and started getting out some more “stuff”. I noticed a line about 3“ up the hull. I cleaned everything the best I can, but still have a strong odor.
Are there any solutions to help me get rid of the smell? It’s in the foam of the mattress as well?
What do you think caused this? It doesn’t appear to be a current problem, but I’m still figuring it out.
Should the mid cabin drain into the bilge area. It doesn’t seem to be.
Thanks for any help or ideas. I’m a new Carver owner.

[Midnightsun]

I can only assume a hose is loose, split or the tank is ruptured. No way can this be diagnosed on the net, gonna need to get down there and find this on your own. As for the smell, clean, clean and clean again preferably with something strong like spray nice or any degreaser.

How full is the tank? Have you had issues when pumping out? could be a blocked vent which would cause excessive pressure in the tank when temperatures increase resulting in a leak.

[mjk1040]

Any standing water after time will smell up a bilge. Shower Sump, Gray or Black water tanks leaking? Dry out the bilge and place some order blocks in there. Home Depot sells an odor killer.