waterlock

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cid

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Hi all I have a stainless water lock and have diyed leaks over the years . I had a major job of repair 2 seasons ago and before I lifted out last October while at first it looks ok it started leaking again. On close examination erosion is visible on the in and out outlet pipes under the connecting hose. Its off for repairs again. The first question is would a anode help to prevent this or am I wasting my time. The second has anybody tried to make a fibreglass waterlock ? Were its located is very tight. I have read many posts on the subject but none the wiser , hence the post. So I am up for trying.
 
Had a similar problem two boats ago. The corrosion you describe under the hoses is likely to be crevice corrosion, no much will stop that, and the other leaks will likely be around the welds where the weld forms a dissimilar metal area where the corrosion goes wild. Also the hot acidic exhaust strips the oxidising coat off the stainless steel, leaving it rampant for corrosion.

A fabricator may be able to make one from copper sheet with brazed joints, or line a new one with a heavy duty epoxy resin.

Another option might be to do away with a waterlock entirely instead use a high swan loop in the rubber hose close to the outlet. My last and current boats did not use waterlocks and instead used swan necks just before the outlets.
 
superheat6k said:
Another option might be to do away with a waterlock entirely instead use a high swan loop in the rubber hose close to the outlet. My last and current boats did not use waterlocks and instead used swan necks just before the outlets.
Click to expand...
The primary reason for the water lock is to collect water running from the highest point of the hose back to the engine preventing water going into the engine. With water lock you should still have swan neck preventing water from the outside entering into the exhaust system.

Vetus stock a lot of different shapes of water locks, have you looked at those?

It should be possible to make in GRP but it’s more than a bucket with two hose tails....
 
IIRC ASAP supplies sell Centek Vernalift grp waterlocks of various sizes and configurations. Fitted one to my boat some years ago and still seems sound.
 
As suggested it is not galvanic corrosion but crevice corrosion or imperfect welds so an anode wont help. In addition to Vetus waterlocks, suggest you look at Halyard Marine who make GRP waterlocks in a variety of sizes and shapes and will also make to your design if a standard one won't suit.
 
knuterikt said:
The primary reason for the water lock is to collect water running from the highest point of the hose back to the engine preventing water going into the engine. With water lock you should still have swan neck preventing water from the outside entering into the exhaust system.

Vetus stock a lot of different shapes of water locks, have you looked at those?

It should be possible to make in GRP but it’s more than a bucket with two hose tails....
Click to expand...

+1 to all that.

cid: GRP's a perfectly acceptable material for waterlocks, as Tranona's post confirms, but the work involved in a DIY job barely justifies the cost compared with a proprietary one. Many (Vetus included) are now injection-moulded plastic. The temperature they handle rarely reaches even 50ºC.
 
macd said:
+1 to all that.

cid: GRP's a perfectly acceptable material for waterlocks, as Tranona's post confirms, but the work involved in a DIY job barely justifies the cost compared with a proprietary one. Many (Vetus included) are now injection-moulded plastic. The temperature they handle rarely reaches even 50ºC.
Click to expand...

Vetus offers a range of waterlocks in all shapes and sizes. A few years ago I fitted a Vetus NLP 45 HD and I have been very pleased with it. The top and bottom chambers have drain cocks and it only takes a few minutes to drain down after sailing. It is able to withstand temperatures of 250°C.
 
superheat6k said:
Had a similar problem two boats ago. The corrosion you describe under the hoses is likely to be crevice corrosion, no much will stop that, and the other leaks will likely be around the welds where the weld forms a dissimilar metal area where the corrosion goes wild. Also the hot acidic exhaust strips the oxidising coat off the stainless steel, leaving it rampant for corrosion.

A fabricator may be able to make one from copper sheet with brazed joints, or line a new one with a heavy duty epoxy resin.

Another option might be to do away with a waterlock entirely instead use a high swan loop in the rubber hose close to the outlet. My last and current boats did not use waterlocks and instead used swan necks just before the outlets.
Click to expand...

+1

When our stainless waterlock failed I just removed it and extended the exhaust hose down into the bilge and back up to the swan neck. The engine (BMC 1.5) is just as quiet with just a straight through exhaust hose.
 
I am just going through the same process.I had a new stainless waterlock made in 2002 and it has just started leaking, having carefully looked at the leak it is crevise corrosion on the loer part of the end plates, the inlet ipes which were solid tube seem ok. I have looked at all the grp/ plastic types but they will not fit, so i am going with a new stainless one. The shape is very simple and has lasted 16 years so if the next one lasts 16 years it will see me out. The ipe dia in mine is 45mm and engine Bukh 20.

Regards
David MH
 
I built a GRP one for a 4-108. The previous Volvo was too small and had allowed water to get back to the engine. The available space didn't suit a Vetus, so it was DIY.
I used 50mm PVC plumbing joints and tube as moulds for the tubing, laying up a thin cloth, then slitting it to get the PVC out. Layed up a decent thickness over that, then bonding them into the box. That was sized for three times the capacity of the Volvo and baffled to stop surging.
 
Listen thanks everybody for your replies. I have limited space. Box size,max, 8 inches long by 9 inches high by 5/6 inches wide. I have sent the existing box for repairs so will stick with it for coming season , but clearly it is not going to last. Might try to make up a fibreglass one.
 
Further to all of the above has anybody got a picture or could direct me to a web site that might have one of the internals of a waterlock.
 
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