Hidden Leak

[keithwatson]

I have Sun Odyssey 42DS (2007) and have a small but continuous leak whilst motor is on but not whilst sailing or at anchor. The yacht has an air conditioning unit and bow thruster.

There is no water in the engine sump and no leak from the drive shaft. The water from the leak is cold and salty. 

I have closed all the stop cocks and checked all the skin fittings, closed all the stop cocks other than engine. Checked the bow thruster. It is not leaking from the engine salt water intake.

I am completely confused as to what the problem may be. The leak appears to come from the starboard side.

Anyone had similar issues or has any suggestions?

Help much appreciated


Keith

[vasko]

Check the exhaust pipe/hose all the way to the exit point from the hull

[keithwatson]

thanks - will do

[keithwatson]

We traced the exhaust from engine through aft cabin and into cockpit locker. There were no leaks and it confirmed that water was not leaking from aft of the engine.

Still appears to be coming from amidships where of course there is no engine coolant water.

Complete mystery.

Anybody have any other ideas. Could it be vibration related ?


Regards


Keith

[iancymru]

What a mystery, you could try smearing water finding paste around the area when dry and see what direction the water is coming from. the paste is like orange toothpaste and turns bright red only where the water touches it .

www.plumbcenter.co.uk/product/regin-rego03-kolor-kut-water-finding-paste-3oz-tube/

you can get it cheaper if you google its handy stuff for checking if yo have water in fuel tank etc.

[aschaab]

This holiday season we had an unfortunate incident with a line having caught in the propeller.

From the stress on the drive shaft the rear shaft bearing bracket appears to have moved slightly and as a result we had a very slight leak through small cracks in the hull mounting og the bearing bracket.

Don't know if this could apply to you as well, just wanted to share this possibility.

Good luck hunting the leak, cheers,
Axel

[aschaab]

PS oh, forgot: the leaking is getting stronger from vibration of the motor or the shaft whereas when sitting in the berth the leaking ceases after a few days.

[Tafika II]

Never had this problem, but you should check the galley sink through hull. We have the same boat and I don't know anything else that might cause the problem on the starboard side egress. Where are you located?

[vasko]

Leaks are very annoying - try with the gel ... mark around all truhulls and diferent places in the bilges to track the source...hope it is not something from a crack ... have you grounded the boat recently ?

[jeroen]

Sept 25, 2017 16:04:00 GMT aschaab said:

This holiday season we had an unfortunate incident with a line having caught in the propeller.

From the stress on the drive shaft the rear shaft bearing bracket appears to have moved slightly and as a result we had a very slight leak through small cracks in the hull mounting og the bearing bracket.

Don't know if this could apply to you as well, just wanted to share this possibility.

Good luck hunting the leak, cheers,
Axel

I had the same few years ago. A line in the propellor caused the P-bracket to decouple from the hull. Salt water came in, only when motoring. Small hair cracks where visible only at the base of the P-bracket block (made from epoxy). Solution: repair the bond between P-bracket and the hull. (2 days work) + cleaning the dust in both rear cabins.

[ianqv]

Is it salt water or engine coolant that is leaking?

[Marulf]

I also had a saltwater leak similar to this. I finally located it to be a leakage from the exhaust/watermuffler.

The muffler is located inside the port engine foundation on my jeanneau 53.

At first I suspected the leakage to be in the threaded fitting for the connection to the exhaust hose, but after some further testing I found that there was a small crack in the side of the exhaust muffler. I could probably have sealed this crack, but as this muffler is not easy to inspect and having in mind that this could possibly be a cause for massive waterleaks (One of my first boats had a massive waterleak after the exhaust muffler cracked open and all the cooling water went directly into the bilge) I replaced it with a new one.

Salt water in bilge

[aschaab]

Sept 26, 2017 7:57:49 GMT jeroen said:

I had the same few years ago. A line in the propellor caused the P-bracket to decouple from the hull. Salt water came in, only when motoring. Small hair cracks where visible only at the base of the P-bracket block (made from epoxy). Solution: repair the bond between P-bracket and the hull. (2 days work) + cleaning the dust in both rear cabins.

Thanks for the feedback, good to hear we're not alone

We are set to do exactly what you described in winter season, plus fixing the vibration in the motor/shaft area ...

[Mistroma]

Double check the exhaust where it touches the bulkheads in art lazarette locker. We had a leak just before it reaches the hull. Only a pinhole and difficult to see without levering the hose away from the woodwork. Cable clips above had broken, allowing the hose to pulse up and down.

If the clips are broken and hose jumps when water is expelled then a leak is likely. We also had wear at the bulkhead nearer the centerline. Again, invisible until hose pulled away and wedged clear of bulkhead.

Water appears in 2 places, depending on exact location of pinhole. Either in area aft of gearbox or bilge areas forward of chart table. In latter case it can seem to be from starboard because there's a channel from stern on port side exiting via a limber hole on starboard side. At least that's what I recall.

I have padding in both areas now but intend to sleeve with 2 short sections or plastic pipe or similar as a better solution.

The exhaust muffler inside the section on port side aft of the engine is the next likely cause.

[keithwatson]

Thanks to all for input and sorry for delay in responding

In response to the various questions

It is definitely salt water

We are based in Licata in Sicily

It is not the sink drain as far as I can see.

Not grounded the yacht


The advice around exhaust, exhaust muffler and P bracket sounds promising.


I am sging back out to the yacht in November and meeting a marine engineer to try to sort. Will report back when the source finally found !

Thanks again

Keith

[ceriabertawe]

One other possibility which fooled me for a long time - was a leak through the rudder bearing. I have a 2 year old SO 33i and water was appearing around the shaft seal. The agent changed the seal under warrantee but the leak continued. It only occurred when under engine with highish revs. Eventually I used flour (didn't have any expensive water finder paste) to trace the source. The rudder bearing was above the water line when the boat was at rest, but I guess the water pressure from the prop was forcing water up higher through the bearing and into the aft bilges. I have twin rudders and only the stb one was leaking. Eventually, the rudder bearing was replaced and the leak fixed.

Hope you can find your leak and fix it.

ceri

[zofiasailing]

Sounds similar to the water mufler/ engine exhaust leak we experienced twice. The leak was only evident when the engine was running.
The first time was because the hose was cross threaded (boat supplied in this condition)and actually a miracle that it held at all. It had probably been knocked during an engine service which was sufficient to break the seal (we think). Problem solved when properly threaded and screwed down.
Some years later the gasket developed a crack. The mufler box is a Vetus part and not a part of the Yanmar engine. Locating a Vetus part proved incredibly difficult so we had a replacement gasket custom cut. It’s been an effective solution.

[andreshs1]

hello

do you have a photo of how that Vetus is fitted?

we have a leak in our 43DS nd I cannot figure out wich vetus to use and where to fit it

cheers 

[whitebird3800]

  I know you have ruled out the exhaust,but,  Our 2003 SO 35s exhaust hose was completely riddled with cracks and leaks and pinholes last season

[tomina]

Just for something different! When you are runnng under engine, particularly at higher revs. The stern will squat by several inches (centimetres). This could be enough to dip the sternpost and a poor rudderbearing seal below water level and produce a leak. A little talcum powder as far to the stern as possible might give a clue.
Michael Solano S/Y Julia Too

[andreshs1]

Hi

I also hoped for the leak on the exhaust hose, but we traced it to the muffler. No water anywhere after the muffler connects to the hose

Cheers

[tarjack977]

Keith,

I have a 2005 Jeanneau SO37 with a similar issue. Only occurs when I sail and the water appears to be coming from the port side rear via the engine well before pooling in the centre of the boat. It's not a lot of water but I find I have to pump out about half a litre a day for about two days after a sail before it stops. 

I've not confirmed it as yet but believe I may have a rudder seal issue. 

Regards,

Tony

[tarjack977]

Sorry, forgot to mention, it's cool, clean salt water. 

[johannes]

The SO37 does not have a rudder seal, the upper rudder bearing is above the waterline.

[tarjack977]

Okay thanks did not know that. Any other suggestions re the leak or can you still get leaks via the rudder on the SO37?

Regards,

Tony