For a year now the boat yard and I have been chasing a mystery leak in my 2001 Marlin. It appears to be coming in somewhat on the port side near the back of the cabin but we can't get to it or see the source. It is salt water but the hull looks perfect. We've plugged through hulls and closed drains and it still slowly takes on water. The fwd bilge will pump out most and we just added a small dry bilge pumping the last to the shower sump. That seems to keep the bilge totally dry and it runs three times a day. I'm desperate for ideas. My brain is mush trying to figure this out.
Salt water in fwd bilge
- Thread starter Oceangopher
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'Course this is just guessing, but it could be coming in under the rubrail. The deck fits over the hull like a shoebox lid. There should be plenty of adhesive goop inbetween the joint, but maybe it's not as "full" of goop as it should be. Use a hose and start spraying spots to see if you can replicate. You could also use something like 4" or 6" shrink wrap or hull preservation tape and completely cover the rubrail. The tape removes nicely - even after being in the sun - very little, if any residue.
Is your aft bilge connected to the forward bilge? Could it be aft bilge water travelling forward under certain conditions? Many Grady's are like this - and the fwd bilge is slightly lower than the aft so some of the water then stays there in the fwd bilge.
I'm not sure what your 5th sentence is saying?
Is your aft bilge connected to the forward bilge? Could it be aft bilge water travelling forward under certain conditions? Many Grady's are like this - and the fwd bilge is slightly lower than the aft so some of the water then stays there in the fwd bilge.
I'm not sure what your 5th sentence is saying?
Thanks for the suggestion I'll give it a try. The aft bilge does connect to the fwd bilge but stays dry and we detect no leaks anywhere there. We had the boat on a lift bow up and totally drained it out. When we put it back in the water it started to accumulate water in the fwd bilge and eventually the pump kicked in. The fwd bilge is definitely the lowest point when afloat.
You could add food coloring or some water soluble dye to the aft bilge to rule that scenario in or out. Easy to do and get results quickly.
Just for clarification... this statement makes it sound like you're getting salt water in there while just sitting in the water. But you're only getting it while underway, right?
We put in a SEAFLO Dry Bilge System. It pumps out the water the fwd bilge pump can't get into the shower sump located just aft of the bilge pump and that small sump pump sends it over the side.
Ah, OK - now I understand about the bilge pumps. Thanks for the clarification.
Just sitting in the water? In that case, it's obviously not the rubrail. The only options are any seacocks, transducers, etc. Unless there's some unnoticed damage.
Are you 100% positive that it's seawater and not just "tainted" fresh water (gathering a salty taste from where it drips/tracks throughout the boat)?
Just sitting in the water? In that case, it's obviously not the rubrail. The only options are any seacocks, transducers, etc. Unless there's some unnoticed damage.
Are you 100% positive that it's seawater and not just "tainted" fresh water (gathering a salty taste from where it drips/tracks throughout the boat)?
Fishtales
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In my marlin, any water that goes into the bilge will collect in the bow area at rest. Could be coming in anywhere. Could water be getting past a thru hole at rest (water between the OD of the thru hole and the glass)? You may need to tape over the entire thru hull on the outside with waterproof tape or a product like StayAfloat. I assume you have a vacuflush head - that would eliminate saltwater. How about the screws that mount the trim tabs? Can't think of much more at rest.
I can't be absolutely positive it is pure sea water. The Gulf of Mexico has be diluted with fresh water for the last couple years. In addition the normal salt content isn't as high as other places due to the Mississippi river run off. It is salty and about the same as everywhere else but could be acquiring the salt from the boat. Good question. Sorry I don't have a better answer.
If the forward bilge is taking on water at rest and you haven't run the fresh water system and it's level is not going down, it sounds like you have a hull leak below the water line. Note that the leak if a fitting, has to be one that is below the water line and that eliminates several possibilities. Raw water pickup for AC is a possibility.
Raw water for washdown is probably aft. I would expect any transducers to also be aft. There may be a livewell through hull mid hull also but I am not sure where the livewell is.
In my opinion, this is something that could end up being serious like a loose hose that if it pops, the boat may sink.
For not shut off all seacocks and see if the water flow stops and go from there. If the flow doesn't stop. I would lean towards hauling the boat to find the leak.
Raw water for washdown is probably aft. I would expect any transducers to also be aft. There may be a livewell through hull mid hull also but I am not sure where the livewell is.
In my opinion, this is something that could end up being serious like a loose hose that if it pops, the boat may sink.
For not shut off all seacocks and see if the water flow stops and go from there. If the flow doesn't stop. I would lean towards hauling the boat to find the leak.
Uncle Joe
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I've never used one, but if I couldn't figure out, for sure, if it was salt water or rain water, I'd pick up a salinity meter and compare it to the water the boat is sitting in. If it IS salt water, I would imagine the reading shoulds be close.
I had a similar problem in my old 272 GW Sailfish. I could not find the problem for the life of me. Aft bilge was dry, all seacocks closed, no rain, no movement, just sitting there and the forward bilge would fill with water until the pump kicked on. I spent months searching. I even dried both bilges with paper towels and put a timelapse video (iPhone technology!) in there to see if I could spot anything. Nothing. Finally I hauled the boat and filled the inside of the bilge with fresh water (I got to clean it too - but make sure you dry it well) and let it sit overnight. In the morning there was a clear drip from the drain plug flange in the transom. It must have been over tightened at some point which broke the seal. For some reason, I never was able to see the water flowing from the aft bilge to the forward. Once I installed a new drain plug, I never had an issue with it again.