Water in "Central" Bilge, Beneteau Oceanis 400

[Fabian Vaca]

Hi All,

It might be a topic that has already been discussed previously but haven't been able to find any information regarding this, any help or ideas would be much appreciated.

Since I bought My Benny Oceanis 400 there has always been a bit of water in the "central' bilge. Initially I though it was because the shape, height and position of the bilge pump didn't allow it to reach that low (water doesn't reach more than 5-8 cm from the bilge floor).

The Keel bolts have always been totally enclosed in resin and it looks like this might have been done since the beginning, as perhaps water has always been there!?

As we always were attracted to this particular Benny, we inspected heaps of them before finding one in really good condition that suited our price range. I remember talking to many dealers and brokers about Oceanis 400, and I recall that all of them had this issue with water in the "central" bilge, and I kind of remember a few of them mentioning it had to do with the positions of the bilge discharge through hole, below the water mark so any tilting of the boat while tacking would slowly let water back in...

last week we decided to sponge out the water while at the marina, and water did cleared, however after a short sail the bilge was back at its 5-8 cm water level...
what puzzles me is that the water just sits at that height all the time and never increases or overflows...

has anyone experience this before?
is it possible that the trough hole below the water line theory is true?
or should i be looking into getting the boat out of the water in an attempt to find a problem with the coupling of the keel and hull?

cheers,
Fabs

 

[Benny17441]

It is common to have many gallons of water trapped in the hull stringers below the sole. The source of that water can be sea spray, rain leaks, wash down water, galley spills and any fouled hoses, tanks, thru-hulls, keel bolts and packing gland drips. That water is usually dislodged with boat movement under sail or subject to sea motion. The trapped water is usually foul and may contain chemical residues of solvents, fuel and oil as well as being accompanied by a foul odor. Getting rid of that water may be a long tedious process which would need to start by correcting leaks and stopping any source. Some have opted to drill and open holes on the bilge liner to pump the water out. Opening the bilge liner may release unwanted smells in the cabin. Trapped water does not release by gravity alone and it entails taking the boat out and putting it through its paces a number of times to release as much of the water as possible. I know of no one that has dried the boat out 100% and no one that can avoid new water from leaking in. Personally I do not worry about it as long as the volume in the bilge remains constant and no foul smells are coming from the bilge. The electric bilge pump with an automatic switch is a convenience item to expel bilge water without having to get on the knees to scoop or sponge water out. The only time I worry is when I do not hear the pump turning on for an extended period of time.

 

[Kings Gambit]

I have a water vac that I use whenever "new" water appears in the bilge area after sailing, which it sometimes does. Just keep sucking it out until it finally disappears, which it may unless being constantly resupplied from somewhere. Evaporation should also help get rid of it so I sometimes leave the floor boards up when off the boat.

 

[Fabian Vaca]

It is common to have many gallons of water trapped in the hull stringers below the sole. The source of that water can be sea spray, rain leaks, wash down water, galley spills and any fouled hoses, tanks, thru-hulls, keel bolts and packing gland drips. That water is usually dislodged with boat movement under sail or subject to sea motion. The trapped water is usually foul and may contain chemical residues of solvents, fuel and oil as well as being accompanied by a foul odor. Getting rid of that water may be a long tedious process which would need to start by correcting leaks and stopping any source. Some have opted to drill and open holes on the bilge liner to pump the water out. Opening the bilge liner may release unwanted smells in the cabin. Trapped water does not release by gravity alone and it entails taking the boat out and putting it through its paces a number of times to release as much of the water as possible. I know of no one that has dried the boat out 100% and no one that can avoid new water from leaking in. Personally I do not worry about it as long as the volume in the bilge remains constant and no foul smells are coming from the bilge. The electric bilge pump with an automatic switch is a convenience item to expel bilge water without having to get on the knees to scoop or sponge water out. The only time I worry is when I do not hear the pump turning on for an extended period of time.

Thanks for your reply Benny17441,

We have checked for leaks of all sort but haven't found any (yet), all cabins and interior does not show signs of smells or leaks or filtered sea spray through the body or rain leaks, she is immaculate inside. Water tank pipes also don't show any leaks. what is confusing me is that There is only water in the "center" liner of the bilge, which happens to be where the keel is joined to the hull, while every other liner is absolutely dry and doesn't show signs of leaks, stains or water passing through at all (no moisture at all) (or oil and chemicals from the engine) to the center one.

we have a electric bilge pump with a manual switch and we barely use it, still, without using it the water never seems to get higher, it just sits at that 5-8 cm level, which i think that if we had a continuous leak from any of the sources you described, would continuously fill the bilge, but that's not the case.

I guess I should try and taste the water to start shortening the list!

 

[Tejas]

As for helping to identify the source of the water, you might want to try a swimming pool pH test strip. Rain water and sea water should have a different pH ,and tankage water might also. I had water in the bilge and the source was tankage via a leaky stern shower. I would never have guessed until tankage was identified as the likely source.

Another source could be the Raw Water Bleed Valve. Beneteau had a service bulletin in a newsletter several years back but I can't find it now. I also had the raw water bleed valve as a source of water in the bilge. It was easy to diagnose. There was a clear plastic tube attached to the bleed valve and and I just put a bottle on the end. The flow wasn't high, but high enough. Again, the source was a mystery for a long time.

Here's the link, but it is dead.
http://www.boat-mail.net/e-beneteau/2011horizons/201103/201103beneteauenewsletter_service.html

 

[Benny17441]

if we had a continuous leak from any of the sources you described, would continuously fill the bilge, but that's not the case.

I guess I should try and taste the water to start shortening the list!

The water that you are getting on the bilge may not likely be overflow from a continuous source. It may likely just be some of the water that has been trapped in the stringers and is being released when you take the boat sailing. The trapped water does not come in all at once and it would be very difficult to get rid of it all at once. Just because the volume of water does not change when the boat is at rest does not eliminate the possibility of some of the sources for leaks that I referred to. When I said you likely have many gallons of water trapped below the sole I meant many gallons, try 20-30 gallons perhaps. Since the level of water does not increase in the bilge I would not bother tasting that water (it should be nasty and perhaps a mix of salt and fresh waters). When I say shutting down the sources for water ingress I meant more looking out for and correcting rain leaks and being careful when hosing the boat down. Keeping sea water spray out may be hard to do as well as persons coming aboard dripping wet after a swim. The fact that it is only your center panel that accumulates water is a good indication that you have no major leaks and the released water just barely fills the bilge. I just remembered another source of water and it is the drain tube for the ice cooler or refrigerator. I would not be concerned about a leak through the keel bolts, the telltale would be a continuous increase in volume for the bilge water.

 

[Fabian Vaca]

The water that you are getting on the bilge may not likely be overflow from a continuous source. It may likely just be some of the water that has been trapped in the stringers and is being released when you take the boat sailing. The trapped water does not come in all at once and it would be very difficult to get rid of it all at once. Just because the volume of water does not change when the boat is at rest does not eliminate the possibility of some of the sources for leaks that I referred to. When I said you likely have many gallons of water trapped below the sole I meant many gallons, try 20-30 gallons perhaps. Since the level of water does not increase in the bilge I would not bother tasting that water (it should be nasty and perhaps a mix of salt and fresh waters). When I say shutting down the sources for water ingress I meant more looking out for and correcting rain leaks and being careful when hosing the boat down. Keeping sea water spray out may be hard to do as well as persons coming aboard dripping wet after a swim. The fact that it is only your center panel that accumulates water is a good indication that you have no major leaks and the released water just barely fills the bilge. I just remembered another source of water and it is the drain tube for the ice cooler or refrigerator. I would not be concerned about a leak through the keel bolts, the telltale would be a continuous increase in volume for the bilge water.

Yeah righto,

thanks for the explanation Benny17441, Im going to get the fridge drain tube checked for leaks (which we use A LOT) and also going to take a whole day continously sailing a bit and then wetvac cleaning the center bilge to see how much I get out... i hope is not gallons, finding out theres so much water inside kind of scares the crap out of me...

any ideas on how to get the water all at once without having to use a sponge or wetvac??

 

[Fabian Vaca]

As for helping to identify the source of the water, you might want to try a swimming pool pH test strip. Rain water and sea water should have a different pH ,and tankage water might also. I had water in the bilge and the source was tankage via a leaky stern shower. I would never have guessed until tankage was identified as the likely source.

Another source could be the Raw Water Bleed Valve. Beneteau had a service bulletin in a newsletter several years back but I can't find it now. I also had the raw water bleed valve as a source of water in the bilge. It was easy to diagnose. There was a clear plastic tube attached to the bleed valve and and I just put a bottle on the end. The flow wasn't high, but high enough. Again, the source was a mystery for a long time.

Here's the link, but it is dead.
http://www.boat-mail.net/e-beneteau/2011horizons/201103/201103beneteauenewsletter_service.html

Thanks for the reply Tejas,

The pool water pH is a great idea so I don't have to taste that water...
I doubt it will have anything to do with raw water bleed as the engine's bilge is very clean and dry all of the time, and also the "bilge pathway" to the center bilge is totally clean, dry and without any sign of stains etc towards the centre bilge (although it might be wrong).

 

[Fabian Vaca]

I have a water vac that I use whenever "new" water appears in the bilge area after sailing, which it sometimes does. Just keep sucking it out until it finally disappears, which it may unless being constantly resupplied from somewhere. Evaporation should also help get rid of it so I sometimes leave the floor boards up when off the boat.

Great idea Kings gambit,

it will definitively beat using the sponge!

 

[Gunni]

My bilge sump typically holds 3 to 5 cm of water. This is roughly the volume of water in the hose to the bilge pump that drains back after pump shutdown. You can decrease the bilge water volume by installing a solid state bilge switch that has a shut-down delay. Water Witch makes a reliable switch that has a 15 second shut-down delay. Your discharge hose should loop up high to your gunwale and then back down to your discharge thru-hull to prevent siphoning of sea water. Make sure your install is correct.

 

[Kings Gambit]

Having saildrive, the situation in my bilge is different from some others. The bilges are essentially flat where the water spreads over the whole bilge (boat at rest) rather than concentrating in a deep pocket. Thus, it does not collect in a convenient spot for automatic pumping out. Five centimeters (2 in) deep of water in my bilge might represent 25-30 gal. I doubt this would even reach the bilge pump; but, if so--only barely. Strange set up, which is why I installed a bilge alarm lower than the bilge switch.

 

[Gunni]

That is strange construction. 25 to 30 gallons of stagnant bilge water can cause real quality of life problems aboard. I'm guessing Fabian's residual bilge water is less than a liter and in a pocket the size of a coffee can.

 

[Kings Gambit]

That is strange construction. 25 to 30 gallons of stagnant bilge water can cause real quality of life problems aboard. I'm guessing Fabian's residual bilge water is less than a liter and in a pocket the size of a coffee can.

Yeah-that's why I endeavor to keep it dry whenever water finds its way in there.

 

[ErikFinn]

If you have a seawater facet in the galley with a pump under the sink, check that pump out very carefully. Mine had a fracture on the hose connection and it could have sank the boat. Very difficult to detect the leak and it was intermittent.

 

[Pilgrimtex]

Friends of ours have a Beneteau 50 Sense. Had it 1.5 yrs. Always had a list. Bottom line France marked but never drilled out the drain holes in the stringers for draining. 50+ gallons later no list. Bottom line they are working to get Beneteau to buy it back.

 

[NiceBeny]

I discovered a pin hole leak on the top of one of my water tanks, it was in a crease and could not be seen, when I was on tack where that tank was tilted the water shot out of the hole, I have fixed it and no more problems