Skin Fitting Leak

[patprice]

Hi All

Help please!

Before launching my B42 Penelope recently I tried to remove the external strainer on the engine raw water intake. I used, unsuccessfully, an impact screwdriver on the screws.

Result, a weep, about 2 litres/day, coming from the skin fitting. From under the nut/flange.

I am not keen to try and tighten the nut! Could make it worse?

Any thoughts on a temporary fix? We are living on board so can monitor the situation until we can get to a slipway. And we do not view it as an emergency.

Thanks for any advice.

PS We are at Poros, Ionion Islands. Very little tide for that to be used.

Pat

[Neil]

2 litres per day is not the end of the world so you could just live with it.

The main concern would be if there is a fundamental problem which could cause the fitting to fail catastrophically - but from what you say that seems unlikely. I would still want to have a float switch on my bilge pump and some of that putty ready for that eventuality.

You could try some one of the sikaflex products to stem the leak if you wanted. It certainly wouldn't any harm other than being a bit messy when you come to looking at it properly when you have it out of the water.

Neil

[PEA-JAY]

Had a similar problem once, the through hull fitting cracked inside the hull and like your strainer the outer rim was screwed into the hull. I had to use a hammer and chisel underwater to remove the outboard end and bung the hole.
Next I  prepared the replacement fitting with plenty of "Plumber's Mait" and of course with help from a friend secured it in place, fitted the ball valve etc. I had to devise a way of holding the outer part of the through hull fitting captive till my friend was able to screw all the inboard pieces into place but this saved an expensive haul out. I didn't use aqualungs then but I was about 35 at the time! 😅

[Impavidus]

Pat.
It could be one of two things. Either you have dislodged the sealant around the skin fitting or possibly the fitting has eroded by de-zincing and applying force to the fitting nut has cracked the fitting below the nut. The latter would be a worry, as it may come apart with boat movement or vibration. Assuming that you sea cock is 1/2 a meter below the waterline and is 25mm ID it will let in 1200 ltrs an hour, if it totally fails, if the hole is bigger the flow will be more. A lot more!

I would get lifted or dried out ASAP. Sail as close as you can to your lift or drying out point. Use the engine as little as possible. Keep your eye on the rate of leaking, its not that bad at the moment and you can deal with the ingress.

However, in the mean time, here are a couple of suggestions if it fails ;
Don't panic! I will take quite a while for the problem to become serious...
Have a plan to deal with the situation and let the crew know what the plan is and any alternatives.
Keep your soft wood bungs to hand and a mallet or hammer to knock one in.
If you don't have any bungs on board think about what you push in the hole if you needed to? EG a carrot, potato, end of a broom with a towel over it, Champagne bottle?  Something else that can be wedged in firmly to the fitting or hole should there be a problem? You don't need to completely stop the water coming in, just reduce it to a level your pumps can cope with. A frightened man with a cushion or towel  will stop a lot of water ingress!
People who have wooden boats re-launched after being out the water a while will tell you a tale or two.

If the fitting does fail in open water you need to think about an alternative water supply to cool the engine to get you in. (the last bit any way) Perhaps from the toilet water inlet, a sink outlet (below the waterline if you have one)?

You can fill a large bucket  with sea water or even fresh water and put the inlet pipe for the raw water into? Keep topping it up and keep the engine revs low as you can. 
I have even used a deck wash pump to supply cooling water to an engine when our raw water pump broke a shaft many years ago.

Let us know how you get on.

Hope this is of help.   

Ant

[Symphony]

Don't think that is a standard Bavaria fit as if the boat has a saildrive then the normal water intake is through the drive. However some people do fit a second intake using a seacock. So you could take the hose (or a new hose) direct to the saildrive and turn the seacock off. Will not help if it is the seal through the hull that has failed, but at least you will be able to run the engine safely.

[patprice]

Pat.
It could be one of two things. Either you have dislodged the sealant around the skin fitting or possibly the fitting has eroded by de-zincing and applying force to the fitting nut has cracked the fitting below the nut. The latter would be a worry, as it may come apart with boat movement or vibration. Assuming that you sea cock is 1/2 a meter below the waterline and is 25mm ID it will let in 1200 ltrs an hour, if it totally fails, if the hole is bigger the flow will be more. A lot more!

I would get lifted or dried out ASAP. Sail as close as you can to your lift or drying out point. Use the engine as little as possible. Keep your eye on the rate of leaking, its not that bad at the moment and you can deal with the ingress.

However, in the mean time, here are a couple of suggestions if it fails ;
Don't panic! I will take quite a while for the problem to become serious...
Have a plan to deal with the situation and let the crew know what the plan is and any alternatives.
Keep your soft wood bungs to hand and a mallet or hammer to knock one in.
If you don't have any bungs on board think about what you push in the hole if you needed to? EG a carrot, potato, end of a broom with a towel over it, Champagne bottle?  Something else that can be wedged in firmly to the fitting or hole should there be a problem? You don't need to completely stop the water coming in, just reduce it to a level your pumps can cope with. A frightened man with a cushion or towel  will stop a lot of water ingress!
People who have wooden boats re-launched after being out the water a while will tell you a tale or two.

If the fitting does fail in open water you need to think about an alternative water supply to cool the engine to get you in. (the last bit any way) Perhaps from the toilet water inlet, a sink outlet (below the waterline if you have one)?

You can fill a large bucket  with sea water or even fresh water and put the inlet pipe for the raw water into? Keep topping it up and keep the engine revs low as you can. 
I have even used a deck wash pump to supply cooling water to an engine when our raw water pump broke a shaft many years ago.

Let us know how you get on.

Hope this is of help.   

Ant

Hello Impavidus and thanks for your well thought out assessment.
I am pretty confident that skin fitting is OK, I moved it slightly and upset the sealant. 2 litres/day is easy to handle. And yes we are monitoring it with our best attention!
Thanks for your ideas. We have tapers at the ready.

[patprice]

Update for anyone interested. The leak has now virtually ceased!

I believe the leakage path was small enough to enable minuscule particles in the seawater to lodge and block the path? Or maybe salt crystals have done something similar?

Either way the news is good but of course I will remove the fitting next time on the slips and rebed.

My Australian yacht with older style packing gland on the prop shaft also does a similar thing. After and during use it drips, like it should, but the dripping stops a couple of days after the yacht is not used.