Just been refilling my forward water tank (42DS) and as it got full I could hear gurgling coming from inside the anchor locker. And a small amount of water was trickling out of the anchor locker drain hole on the port bow waterline outlet.
Anyone know if there’s a breather hole or overflow hidden in there somewhere?
I concur! For the 42DS the forward tank overflows/breathes into the anchor locker which has an outflow low down near the waterline on the s/b side. The rear tank overflows/breathes through an outflow high on the rear s/b quarter. Tim Peacock
The breather is high up on port side in the anchor locker as already confirmed in 2 earlier posts. You can see it if you duck your head inside but it's not exactly a comfortable position.
It is worth mentioning that the tubing runs back from there to the aft end of the forward tank and may well sag en-route. I found that our vent was full of stagnant water. Well worth overfilling gently to flush it out next time. Have a look at the pipe when laying up. Unscrew the ply above the tank and remove it to get access. I removed the pipe, unthreaded it from some cable ties and then tied it up to a line from the hatch. I could then pour in fairly hot strong bleach solution and leave for several hours. The bleach is easily drained out by putting the pipe end into a bucket and lowering it back to tank level. Repeat with bleach if required and again 1-2 times with water before threading back into place and re-connecting.
I pulled the hose straight when re-fitting and is still seems to be fine. Yours might be OK but could also be pretty gross if it has sagged. No problem with aft tank as that's a downhill run with almost no horizontal section where water can pool.
Just use household bleach. No contamination in tank as it is flushed before re-connecting. Not that it would be a problem anyway as a small amount of sodium metabisulphite solution could be used to kill excess bleach. Any excess sulphite will quickly turn to tasteless sulphate after exposure to water during filling (as it is oxygenated).
Agree with the vent in the anchor locker. Want to float something by you guys while I have you. My tanks both seem to be leaking water into the bilge when I fill (overfill?) them. I haven’t pulled the bunks up and watched to see where it squirts out but curious if anyone else has a similar issue. I guess maybe my vent line could have popped off or something.
There are a few possibilities and they probably apply to most Jeanneau models. It looks as if you have a 42DS similar to mine. Your post seems to indicate that you don't get any leaks after using a little water, only when full.
1) Leak from access port Quite possible that it has not been tightened properly. I have had a leak from an access port once and I'd guess it's the most likely one. I always lift the berth cushions for first fill each season and put tissue around the red access cover. Overfill gently so that there's some pressure from the head of water in the filler tubing. Quite easy to spot a leak in from the cover. I remove them each winter when cleaning the tanks and leave a little vinegar in the tanks and lines. Lines are drained afterwards. Try not to over tighten the red cover, just enough to stop a leak.
2) Leak from filler or breather These are usually pretty well attached with jubilee clips. Same procedure as above, fill completely and put some tissue on the hose. Access is easy enough for my aft tank, just lift the ply cover to see the tank and put tissue at point hoses go through the bulkhead. There are 2 screws on the cover, one at either end. Front tank ply has about 6 screws and hoses are at back on port side.
3) Split in the tank Unlikely and I'd pretty much forget this one unless all else fails. I can't see how you would get a split right at the very top of the tank as there aren't any seams in that area. Hose points are pretty robust and no seams there either but you will have already checked that area (item 2 above).