Mysterious leak

[suem]

Hello,

Last year we bought a SO 42DS (2006). It is our first boat, so there is lots to learn, but we have one specific question I wonder if someone can help us with, please.

We have noticed that when we come back into port, a short time after we turn off the engine (maybe 5-10 minutes, but I haven't timed it), there is a gurgle and water spurts out from under the step in the sugar scoop leaving the trail you can see in the attached photos. The 'leak' always follows the same trajectory. I think it is sea water, not fresh, but then perhaps it tastes salty because of salt on the sugar scoop.

We think this is new, that it wasn't happening last year, and we assume that it has something to do with the engine, but maybe that is just coincidence. There is no water in the lazarette, so no evidence of a leak in the outlet pipe from the engine.

There are three outlets under the step (we haven't worked out what they are all for yet!), but the source of the 'leak' seems to be off to the right, not under any of the outlets.

If anyone has any ideas as to what the problem is (if indeed it is a problem), we would love to hear them.

Many thanks in advance. 

[Chris Meyer]

Aug 11, 2021 13:16:29 GMT suem said:

Hello,

Last year we bought a SO 42DS (2006). It is our first boat, so there is lots to learn, but we have one specific question I wonder if someone can help us with, please.

We have noticed that when we come back into port, a short time after we turn off the engine (maybe 5-10 minutes, but I haven't timed it), there is a gurgle and water spurts out from under the step in the sugar scoop leaving the trail you can see in the attached photos. The 'leak' always follows the same trajectory. I think it is sea water, not fresh, but then perhaps it tastes salty because of salt on the sugar scoop.

We think this is new, that it wasn't happening last year, and we assume that it has something to do with the engine, but maybe that is just coincidence. There is no water in the lazarette, so no evidence of a leak in the outlet pipe from the engine.

There are three outlets under the step (we haven't worked out what they are all for yet!), but the source of the 'leak' seems to be off to the right, not under any of the outlets.

If anyone has any ideas as to what the problem is (if indeed it is a problem), we would love to hear them.

Many thanks in advance. 

Hi Suem,

Have you turned on the engine and gone underneath towards the stern platform?   Could it be a leak in the engine water cooling? 
What about a leak in the shower outlet at the stern?   Was your fresh water on?

I am sure you will find this.

Chris


 

[Tafika II]

This is the discharge area from the forward automatic bilge pumps. It the way Jeanneau design it.

[NZL50505]

I think the cockpit drains also come out here on some vintages (one from each of the two helm positions).

[suem]

Many thanks for those helpful suggestions, especially that it could be/is the forward automatic bilge pump. Does that mean we have a leak somewhere up front? I guess it must ... the water has got to come from somewhere, and presumably (as it's salty) this is coming from outside. 

We are pretty sure it's not the shower outlet because we found and mended that leak.   And we haven't yet got water in the cockpit while sailing ... we're taking things very gently at the moment, while we test everything out. But we'll certainly have another root around under the step to make sure we know what those three outlets are for. 

Thanks again.

SueM

[neworca1]

Hi SueM,
If the water is coming from the automatic bilge pump, its source could be a leak in the stainless steel water lift muffler, which is prone to corrode and start leaking in boats about the age of yours (and mine). There is a very useful thread on this issue elsewhere here on the Forum.
Cheers, 
Jim

[Trevor]

As Brent said ( Tafika ll) that location is the bilge pump outlet. You also have the outlets from both scuppers from both helm positions there. Sounds like the bilge pump is just pumping a little bit of water from the sump. The sound you are hearing would be the Johnston pump just behind the settee on the starboard side and just forward of the refrigerator.

[NZL50505]

Once it has done this once following arrival at marina and engine shutdown, does it continue to happening or is it a one-time event?

If it continues, that obviously suggests not engine-related.. But if just once or twice after engine shutdown and then stops, then it sounds like a running the engine is causing a leak. In which case do you notice the water discharging onto the transom step whilst underway under engine? You might not hear it due yo engine mouse but might see it?

But if it only happens when you’ve stopped then maybe the small amount of water that has leaked in runs forward when the boat is stationery and reverts to flat trim (as opposed to slightly stern-down when underway)?

Have you checked stern gland? That’s the kind of thing that would wrap a small but noticeable amount under engine. Not a dangerous amount but enough to trigger your bilge pump if it’s getting worn or needs re-greasing.

[suem]

Goodness ... thank you so much for all those helpful comments and suggestions. It gives us plenty of ideas to work on. We plan to go over to the boat in the next couple of weeks, so will investigate further ... and in the meantime I'll have a look at that Forum thread on the water lift muffler.

The leak seems to be a one-time event, after we turn off the engine, ie I don't think it happens while we are motoring along, but I'll pay more attention now.

Renewed thanks.

SueM

[Mistroma]

All good advice. It is almost certainly the electric bilge pump as others have said. It is located on starboard side beside the fresh water pump.

You need quite a lot of water to get into the sump as there's a fairly high lip. It will be obvious that water is in virtually every saloon bilge area (apart from galley and in front of steps). If you can't see any water then it is likely to be coming from the hot water tank PRV (pressure relief valve). It is common hear the odd chu-chug-chug from the bilge pump after motoring as the water gets very hot and some comes out from the valve if don't use any hot water. The leak is normally very slow and takes ages to build up. You would certainly have noticed if the valve was leaking badly and the pump was running regularly. Look no further if you can't see water sloshing around in the bilges or feel dried salt crystals.

Water in the next section between the galley and chart table (not the one at the steps) is almost certain to be coming from the aft. cabin area. Exhaust leaks, water tank leak or a Volvo seal leak all tend to leave a pool of water behind the engine (or dried salt crystals). It drains through a hole in a small raised section close to the gearbox. You won't see anything under the engine as that area doesn't have a low drain hole at the bow end.

It will be interesting to hear if it is the usual PRV leak. The symptoms point to the PRV, apart from salty taste. However, that can be explained by salt on the step as you suggested.

[suem]

Many thanks for the additional ideas, Mistroma.

We are just back from a week on the boat and can now say yes, the water is coming from the forward bilge pump, but the bilges are dry. So it seems the next thing to check is the hot water tank (PRV). If it is the PRV, would it still leak (and the bilge pump start working every so often) when the boat is on shore power, or does the water heat up less under shore power? 

I said the bilges are dry ... well, they have been up to now, but when we got back to port on the final day just now there was some water (a centimeter perhaps) in the bilge between the chart table and the galley. Not enough to flow forward to the bilge pump, just sitting in that one bilge. (Stupidly, I didn't taste it to see if it was salt or fresh water.) The other bilges were all dry. So we'll add that to the list of things to be investigated next time we are on the boat! 

This is very much a newbie question, but how worried should one be if there is a bit of water in the bilges after we have been out sailing? They are always dry when we get back to the boat after it's been left for a month or so. Is it "normal" or acceptable to have a little water in the bilges when we've been out, or do we need to worry whenever we see some? Having read some of the comments elsewhere on this forum, I think the answer is probably that we should aim to have dry bilges at all times ... and if not, to find out where the water is coming from, but would be interested to hear your opinions.

SueM

[johannes]

Small leaks are normal, in the sense that not every boat has them but a good percentage of them. You can either just live with it, or decide you can't and start hunting the source. It is not something you particularly have to worry about. 

[Mistroma]

Sept 5, 2021 12:31:20 GMT suem said:

Many thanks for the additional ideas, Mistroma.

We are just back from a week on the boat and can now say yes, the water is coming from the forward bilge pump, but the bilges are dry. So it seems the next thing to check is the hot water tank (PRV). If it is the PRV, would it still leak (and the bilge pump start working every so often) when the boat is on shore power, or does the water heat up less under shore power? 

I said the bilges are dry ... well, they have been up to now, but when we got back to port on the final day just now there was some water (a centimeter perhaps) in the bilge between the chart table and the galley. Not enough to flow forward to the bilge pump, just sitting in that one bilge. (Stupidly, I didn't taste it to see if it was salt or fresh water.) The other bilges were all dry. So we'll add that to the list of things to be investigated next time we are on the boat! 

This is very much a newbie question, but how worried should one be if there is a bit of water in the bilges after we have been out sailing? They are always dry when we get back to the boat after it's been left for a month or so. Is it "normal" or acceptable to have a little water in the bilges when we've been out, or do we need to worry whenever we see some? Having read some of the comments elsewhere on this forum, I think the answer is probably that we should aim to have dry bilges at all times ... and if not, to find out where the water is coming from, but would be interested to hear your opinions.

SueM

Our PRV does tend to leak more after engine runs than on shore power. The engine gets our tank to a much higher temperature than the heating element. I think the thermostat is set fairly low, perhaps 70-75C. The engine jut keeps heating the tank and I think it must be 90C+ at times (never measured it). We certainly get hot-water for longer after long engine runs than using the generator until the thermostat turns the element off. I rarely use the generator to heat water on 230V but have noticed the effect.


A small amount of water in the bilge you mention isn't from the PRV. You would have to fill the sump, central bilge and then bilges further aft.

I'd bet that the galley bilges and on in front of the steps are both dry. Lots of options here though and a few are:

Salt water:
Exhaust hose, muffler or volvo seal are reasonably common sources. Check for water in the aft. cabin near the prop. shaft. Lift the narrow floorboard and remove the back engine panel (it just pulls back to release clips). You might find a small pool of water in front of a raised hole. Water flows into the bilge you mentioned earlier when it reaches the hole. Check the small depression under the Volvo seal, water there means that it may be the source. Easy enough to dry out and monitor with a tissue to check. The exhaust hoes sometimes wears on a bulkhead near the stern and you get a little water running back to the same area (but not in the depression under the seal). Muffler is a bigger issue and I'll ignore it as there are threads here covering it in detail.


Fresh water:
Main culprit would be the aft. water tank and hoses. Pretty unlikely as the tank locker isn't drained and you'd need a huge amount to overflow the locker. Nobody is likely to leave the tank filling for long enough to also fill the locker.
A more likely source would be loose or damaged hoses. However, all of these are near the top of the tank and would only leak when the tank is full and boat heeled.

I'd say the tank isn't a likely source. A deck leak after rain is far more likely but you didn't mention rain.

[suem]

Thanks again for your really helpful and detailed comments, Mistroma.

Yes, the galley bilges and one in front of steps were both dry, and the narrow bilge aft of the engine, under the prop shaft was also dry. And no, we hadn't had any rain.

However, earlier in the week before we had been out sailing we did check under the engine and found a small amount of water there. At the same time we also removed a whole lot of gunk (including a large nut and screw!) from the small raised hole. So perhaps having done that when we were out sailing and using the engine water was able to run forward from under the engine into the bilge between the galley and the chart table. Have I understood that correctly ... that's what might be happening? However, the water in the bilge between the galley and the chart table was clean, no sign of oil or anything from the bilge under the engine. 

We'll be back on the boat in a couple of weeks and will check if the water is fresh or salt, have a look at the Volvo seal and exhaust hose ... and continue the search for where this water is coming from.

And thanks Johannes for your reassurance!

SueM

[Mistroma]

Sept 7, 2021 9:50:14 GMT suem said:

Thanks again for your really helpful and detailed comments, Mistroma.

Yes, the galley bilges and one in front of steps were both dry, and the narrow bilge aft of the engine, under the prop shaft was also dry. And no, we hadn't had any rain.

However, earlier in the week before we had been out sailing we did check under the engine and found a small amount of water there. At the same time we also removed a whole lot of gunk (including a large nut and screw!) from the small raised hole. So perhaps having done that when we were out sailing and using the engine water was able to run forward from under the engine into the bilge between the galley and the chart table. Have I understood that correctly ... that's what might be happening? However, the water in the bilge between the galley and the chart table was clean, no sign of oil or anything from the bilge under the engine. 

We'll be back on the boat in a couple of weeks and will check if the water is fresh or salt, have a look at the Volvo seal and exhaust hose ... and continue the search for where this water is coming from.

And thanks Johannes for your reassurance!

SueM

All useful information. Lack of water behind the engine means it isn't salt water from the exhaust hose or the Volvo seal. You would feel lots of salt crystals in that area if a leak had dried out. It gets hot in the area under the prop shaft and the hole is slightly raised. Water overflows and runs through the hole but always leaves a pool behind and that often dries, leaving obvious salt crystals. No water or obvious salt would be good evidence that the leak is further forward. Fresh water wouldn't leave salt behind but you haven't had rain and the aft. tank isn't a likely source.

I think Volvo seal and exhaust hose leaks aren't likely on evidence so far.

The hole doesn't drain into the engine pan on my 2009 42DS. Water has to fill that area under the engine and flow over the top of the small bulkhead with the hole. It runs forward on my boat and even a small amount is obvious. I've only ever seen a dribble of coloured antifreeze there but you could get clear salt water from the raw water side. I'd rule that out unless there's a lot of water sloshing around in there. The pan is sealed and water can only drain forward by overflowing aft part of the pan.

Curvature of the hull directs water forward and any leak from the aft head or galley would run through the dry bilge areas. If only the bilge with the sump is wet then that limits most leaks from aft of the saloon seating area.

Water can run back from the bows if the log fitting is leaking. The fresh water tank has a high bulkhead behind it and isn't a likely source.

I'm running out of possibilities now. I did have a leak from one hull window and it drained into the main bilge. I found it quite quickly as only one bilge affected, sump was dry, only after being well heeled etc. Not difficult to fix.

Try to check the sump frequently. If bilges remain dry and sump is wet that does point to the PRV. The main problem with that plan is the fact the sump will empty slightly when well heeled. It leaves you with a part filled sump and a wet bilge, making you think the leak is somewhere else.

Another source is the mast. We have a pipe glassed into the deck inside the mast to carry wires below deck. It has a slight curve, touches the mast and some wires come straight down into it. However, it only leaked in dreadful weather of heavy rain. I fixed that easily by folding the wires down and pushing the bottom part of a plastic bottle over everything. It can only leak now if there's a foot of water over the base of the mast (or periscope as I'd be referring to it by then). It is worth knowing about but isn't usually a problem. Access is a bit fiddly through the small ports in the side of the mast.

[suem]

That's all really useful to know ... helps rule out a few of the possible sources and to narrow things down. We'll keep monitoring what's happening in the bilges and report back when we've worked it out. Ever the optimist!

Many thanks again for the detailed reply,

SueM