1987 SeaRay 390

[Prokop]

Have a leak in the onboard fresh water system. It appears to be with the holding tank under the deck in the galley. Water in bilges in engine compartment is brown in color which would indicate the wood enclosing the water tank is close to the source. Only access is the storage beneath the galley deck. Short of removing the rug-covered deck at the aft end of galley, any suggestions to confirm. Fittings on the metal tank appear to not be the source of the leak.

 

[cfd95]

Very common problem with that generation of 390.
Tank probably has a hole in it.
Search the site there are numerous threads on this subject.

 

[fwebster]

There have been about as many 390EC's with leaks in the bilge sump walls as there have been water tank failures.

The forward and aft bilge sums in the engine room are formed by building a little v-shaped dam out of wood then fiberglassing it into the V shape in the bottom of the hull to form a sump or catch basin for bilge water. Sometimes, the fiberglass/resin used to cover the wood dam gets voids in it and bilge water flows thru the void thus passing between the engine room and the area below the water tank compartment. Over time, the water trapped builds up. Since it is laying in an area filled with closed cell foam and trapped by plywood the water eventually turns brown and smells horrible.

I had the above happen to my 390. When we figured out what was happening, I used a shop-vac and removed about 60 gal of water. I cut 4" dia holes in front of the water tank and installed inspection ports in them then dug out all t he old soggy foam that I could. It took about 9 months to get the area completely dry.

To find if this is your problem, I would vacuum all the water out of the engine room and dry the bilge sumps with paper towels, wipe the sumps bottom and ends with acetone, let the area evaporate then watch the forward and aft sump walls with a strong light so you can see water re-entering the sump if it is going to.

This is one of those things that might not be your problem, but it is a non-destructive and checp way to rule out a problem common to your boat model. You might well still have to destroy the salon to remove the water tank, but I'd try anything I could to try not to do a forced remodel.