Water tank

[Fuel__2001]

Not sure how to go about this problem, so I thought I better ask.

 

Ive got a Liverpool widebeam (NBC) with a stainless steel water tank which i think has a leak. As the boat is moored on brackish water there is no leak from the hull as the water in the bilge is fresh. We've check all the other pipework and the floors are dry everywhere else,so everything seems to point to the water tank.

 

The water in the bilge is consistent and every few weeks has to be pumped out.

 

The problem is there are no access hatches cut into the bow and the water tank has been welded in.

 

Would it be easier to cut into the bow deck and lift the floor or go in at the lowest point of the fore cabin?

 

As an after thought, what could be put in place so that access to the water tank in the future doesn't involve angle grinding and welding?

 

TIA

[RLWP]

Not sure how to go about this problem, so I thought I better ask.

 

Ive got a Liverpool widebeam (NBC) with a stainless steel water tank which i think has a leak. As the boat is moored on brackish water there is no leak from the hull as the water in the bilge is fresh. We've check all the other pipework and the floors are dry everywhere else,so everything seems to point to the water tank.

 

The water in the bilge is consistent and every few weeks has to be pumped out.

 

The problem is there are no access hatches cut into the bow and the water tank has been welded in.

 

Would it be easier to cut into the bow deck and lift the floor or go in at the lowest point of the fore cabin?

 

As an after thought, what could be put in place so that access to the water tank in the future doesn't involve angle grinding and welding?

 

TIA

 

Is there any way you can get an idea of how much water is going out of the tank? I guess not as most widebeams are liveaboards. I was wondering you could prove that the water was leaving the tank because the level was dropping.

 

Richard

[bargemast]

Is there no possibility to see the welds around the front bulkhead where your watertank is welded in, as if the tank is leaking there should be a trace of water visible from there. It may be difficult if there's no or not enough space under the well-deck, but you should be able to check if the water is really arriving from the tank if the bottom plates up front are getting wet after all water has been pumped out. Because the bows are normally not as deep in the water then the stern you should find the source.

 

If your really have to replace or repair the watertank, you could always make a hatch in the deck above that will give you future access if needed.

 

Peter.

[steelaway]

Not sure how to go about this problem, so I thought I better ask.

 

Ive got a Liverpool widebeam (NBC) with a stainless steel water tank which i think has a leak. As the boat is moored on brackish water there is no leak from the hull as the water in the bilge is fresh. We've check all the other pipework and the floors are dry everywhere else,so everything seems to point to the water tank.

 

The water in the bilge is consistent and every few weeks has to be pumped out.

 

The problem is there are no access hatches cut into the bow and the water tank has been welded in.

 

Would it be easier to cut into the bow deck and lift the floor or go in at the lowest point of the fore cabin?

 

As an after thought, what could be put in place so that access to the water tank in the future doesn't involve angle grinding and welding?

 

TIA

 

Hi

I cant imagine why they would want to weld a plate across the bow inside.

A piece of ply lineing would be all thats needed and leave the tank acessable

Have you checked the outlet valve or the filler pipe.

 

Alex

[jelunga]

Hi

I cant imagine why they would want to weld a plate across the bow inside.

A piece of ply lineing would be all thats needed and leave the tank acessable

Have you checked the outlet valve or the filler pipe.

 

Alex

 

Could it also be a pipe / joint / pump in the system that is leaking, not the actual tank.

 

How old is the boat?

[Guest]

Hi

I cant imagine why they would want to weld a plate across the bow inside.

A piece of ply lineing would be all thats needed and leave the tank acessable

Have you checked the outlet valve or the filler pipe.

 

Alex

That is how I did ours. The tank is under the front cratch, and it would require removal of the stove and one cupboard to get it out. PITA but possible to do. I too doubt if the tank is enclosed by a welded bulkhead or similar.

 

As an aside, whilst I like the idea of a stainless tank (cleaner and no blacking,) I must say that quite a lot seem to be springing leaks as time goes on.

[David Mack]

Not sure how to go about this problem, so I thought I better ask.

 

Ive got a Liverpool widebeam (NBC) with a stainless steel water tank which i think has a leak. As the boat is moored on brackish water there is no leak from the hull as the water in the bilge is fresh. We've check all the other pipework and the floors are dry everywhere else,so everything seems to point to the water tank.

 

The water in the bilge is consistent and every few weeks has to be pumped out.

 

The problem is there are no access hatches cut into the bow and the water tank has been welded in.

 

Would it be easier to cut into the bow deck and lift the floor or go in at the lowest point of the fore cabin?

 

As an after thought, what could be put in place so that access to the water tank in the future doesn't involve angle grinding and welding?

 

TIA

 

If you can get to all the tank connections I would be inclined to drain the tank and carry out an air test. If the tank will hold even a modest air pressure for any time, then it won't be leaking and you can look elsewhere for the source of the water. If it won't hold air pressure, then at least you know it is the tank that is the problem.

 

I assume you have checked that it is not rainwater getting in somewhere.

 

David

[Keeping Up]

That is how I did ours. The tank is under the front cratch, and it would require removal of the stove and one cupboard to get it out. PITA but possible to do. I too doubt if the tank is enclosed by a welded bulkhead or similar.

 

As an aside, whilst I like the idea of a stainless tank (cleaner and no blacking,) I must say that quite a lot seem to be springing leaks as time goes on.

 

Maybe a lot of boat builders don't know how to weld stainless steel properly? I've never tried it myself but I've always been told that it's more difficult than welding mild steel.

 

Our water tank and our holding tank are both stainless steel. So far (touch wood) they are both watertight, the only problems have been the boat builder's stupid idea to use mild steel for the internal pipe of the holding tank and the collar that the toilet attached to - in both cases, unsurprisingly, the mild steel went rusty

[RLWP]

If you can get to all the tank connections I would be inclined to drain the tank and carry out an air test. If the tank will hold even a modest air pressure for any time, then it won't be leaking and you can look elsewhere for the source of the water. If it won't hold air pressure, then at least you know it is the tank that is the problem.

 

I assume you have checked that it is not rainwater getting in somewhere.

 

David

 

Why do you need to drain the tank to do an air test? The test would still work even if there is water already in it. The air test is a really good idea

 

 

Richard

[Pie Eater]

Put some brightly coloured food dye in the water tank to confirm that it is leaking.

 

Steve

[Guest]

Maybe a lot of boat builders don't know how to weld stainless steel properly? I've never tried it myself but I've always been told that it's more difficult than welding mild steel.

 

Our water tank and our holding tank are both stainless steel. So far (touch wood) they are both watertight, the only problems have been the boat builder's stupid idea to use mild steel for the internal pipe of the holding tank and the collar that the toilet attached to - in both cases, unsurprisingly, the mild steel went rusty

A welder told me that the welds should be pickled and something else with a very strong acid after welding. Don't know if that is correct, but if so mine cant have been done as there is no access to the internal welds (I doubt if they filled it with the acid to do so.)

 

A quick Google would seem to back this up:

 

http://www.picklingandpassivation.com/why-to-pickle.html

Edited September 26, 2010 by Guest

[RobinJ]

Put some brightly coloured food dye in the water tank to confirm that it is leaking.

That will also confirm its not condensation!