Fuel in bilge after topping off

[scottymags]

Just bought a 1979 Albin 43 with a single 120 Lehman and 2x200 gallon fuel tanks. Bringing it home was a 4 hour journey. At about 3.5 hours in, we stopped to top off the tanks and then continued home for 30 minutes. While topping off the tanks, the guy responsible for the starboard tank (my FIL) got distracted talking to the dock master and the vent started spouting diesel. Not sure how long that was happening. Cleaned up after ourselves, apologized to the dock master, and left. Weather was calm and we ran it at about 1600rpm the rest of the way home thinking nothing of it.

While we were docking, which admittedly took a couple tries, I noticed purple diesel fuel in the water. We tied her up in the slip and checked the bilge...full of diesel.

Over the next 24 hours, we emptied the bilge into a barrel...about 30 gallons of diesel came out of the bilge. We narrowed it down to the starboard tank, which was overfilled by my FIL...bless his chatty heart.

The leak was seeping slowly down the interior wall of the bilge, but we can't identify the leak source. Could be the overflow valve or maybe a leak at the top of the tank. Previous owner says she never filled the tanks fully and that she's never had a fuel leak. The bilge was spotless and odor-free when we bought her...and even after a 30-minute sea trial and survey nothing was caught nor was there diesel in the bilge.

Any clues that might point us in the right direction? Please?

[kerrye]

First thing I'd check is where the fill and vent hoses attach to the tank.

[catalina_mike]

Level sender also..

[jleonard]

Level sender also..

Yes this got me once on my "ex" boat and I saw another boat leak this way also.

[Chester B]

While doing the loop last year we also discovered fuel in the bilge. It turns out the vent hoses had rotted near the tank connection and have to be replaced. My guess is the hoses are both old and probably not meant for fuel. Our solution was to make sure we did not completely fill the tanks (we have sight tubes on both tanks) and never had a problem after that.