Leaking front water SS tank...

[Akestor]

Hello!
The front SS water tank started to leak...It's a Westerly Longbow 31, and the tank is installed under the V-birth, the only option for removing it is surgery on the fiberglass and then rebuilding it... It's frustrating to have to begin a massive job only to repair a small leak...

I suppose the leak is on a seam and since the tank is 50 years old might not be worth it to repair it and get a new leak in another spot sooner or later.
So I'll need to build a custom plywood tank or at least insert a flexible water tank in there which obviously is not optimal for capacity but an easier solution
Would like to hear from the people who did this and what solution was found for their new tank.

 

[Seastoke]

Could you not cut a hole in the top to get your arm in , clean out tank then pour 10 mm of bitumen in , if the leak is at the bottom.

 

[Snowgoose-1]

Could you not cut a hole in the top to get your arm in , clean out tank then pour 10 mm of bitumen in .

Could you not cut a hole in the top to get your arm in , clean out tank then pour 10 mm of bitumen in , if the leak is at the bottom.

Also, any chance of working a liner in somehow ?

 

[RivalRedwing]

A liner sounds like a better option that bitumen, not much capacity lost, can't imagine bitumen would improve the taste of the water either.

 

[Akestor]

Thank you for your replies. The only access point is through the inspection hatch. problem is that the tank has 2 walls inside for minimizing the water motion. So there are 3 compartments in the tank and have access only to the middle one...I'll have to cut the internal walls to see the other compartments.
I read around that bitumen tape is ok for water tanks, ( we don't drink from the tan by the way..) if I can have access to all areas then that could be a solution.
What do you mean by liner? Like a flexible rubber tank inside the ss tank?

 

[Tranona]

Realistically there is no alternative to removing the tank and identifying where the leak is. It is almost certainly a failed weld, probably in the most inaccessible place. You may be able to get it rewelded or patched and have all the other seams inspected at the same time. While inserted a flexible tank may work in some situations, you have a baffled tank which rules this out.

If the tank cannot be repaired the alternatives are a shaped flexible tank or have a new one custom made, preferably plastic rather than metal. The best people to do this are Tek Tank, but not cheap.

 

[LadyInBed]

Have you pressure tested the tank, done anything to pinpoint the source?
It could be a connection problem.

 

[westernman]

Could be worse. Ask Bouba about his diesel tank leak and how many years it took for him to get it fixed.

 

[Wansworth]

Wernt water tanks coated with a cement wash

 

[Akestor]

Have you pressure tested the tank, done anything to pinpoint the source?
It could be a connection problem.

"Unfortunately", all hose connections are dry and good...Its leaking around 2 glasses of water in 24hours.

 

[Akestor]

Realistically there is no alternative to removing the tank and identifying where the leak is. It is almost certainly a failed weld, probably in the most inaccessible place. You may be able to get it rewelded or patched and have all the other seams inspected at the same time. While inserted a flexible tank may work in some situations, you have a baffled tank which rules this out.

If the tank cannot be repaired the alternatives are a shaped flexible tank or have a new one custom made, preferably plastic rather than metal. The best people to do this are Tek Tank, but not cheap.

Yes, I must admit this is a problem with no shortcut and definitely a major project cutting the V-birth fiberglass, I cannot even know where to cut the fiberglass because I cannot see the edges of the tank. I'll probably empty it and live with the rare tanks only...Thumbs down for Westerly who encapsulated the damn tank lol...

 

[Akestor]

Wernt water tanks coated with a cement wash

No coating in the internal of the tanks. Just the SS sheet

 

[Tranona]

Yes, I must admit this is a problem with no shortcut and definitely a major project cutting the V-birth fiberglass, I cannot even know where to cut the fiberglass because I cannot see the edges of the tank. I'll probably empty it and live with the rare tanks only...Thumbs down for Westerly who encapsulated the damn tank lol...

You are not alone. Some seem to think stainless tanks last forever. I had similar with a Bavaria . The original plastic water tank failed and The Greek manager of the boat replaced it with a stainless one. He chocked it in and then foamed it. Inevitably it leaked when it was filled before a long trip across the Med. Emptied it and relied just on the aft tank until we got back to UK. Took me 2 days to get it out including cutting out part of the GRP berth top.. Fortunately it was repairable and I put it back in properly on a glassed in platform and bolted to the bulkheads through brackets I had welded on it

 

[Akestor]

You are not alone. Some seem to think stainless tanks last forever. I had similar with a Bavaria . The original plastic water tank failed and The Greek manager of the boat replaced it with a stainless one. He chocked it in and then foamed it. Inevitably it leaked when it was filled before a long trip across the Med. Emptied it and relied just on the aft tank until we got back to UK. Took me 2 days to get it out including cutting out part of the GRP berth top.. Fortunately it was repairable and I put it back in properly on a glassed in platform and bolted to the bulkheads through brackets I had welded on it

Sounds like a big job you did! especially with the added foam...What power tool did you use for cutting the GRP? Would like to avoid an angle grinder- will create a terrible glass cloud in the cabin!

 

[Concerto]

I agree the best solution would be the removal and replacement of the tank. However, considering the age of the boat I would remove and have the tank repaired. On my Fulmar I had a leak from a weld on my stainless steel water tank and it only cost £30 to get it tested, welded and retested. Fortunately my tank was bolted in place not glassed in. I would suggest removing the glassfibre by cutting tight along the hull sides using a multitool as you will be highly unlikely to touch the tank. This will still cause some dust, but nowhere near as much as an angle grinder. The glassfibre may have bonded to the tank top, but should not cause any problem for the repair as the leak is unlikely to be at the top of the tank.

 

[Wansworth]

No coating in the internal of the tanks. Just the SS sheet

No I remember that galvanized water tanks were cement washed ,not really helpful to you

 

[Macka1706]

Baffle internal plates. No internal tank poss without removal. Drill a few small pilot holes On each side of top of glass. Find ends of tank. Jigsaw and vac cleaner for dust.
Take out tank. Probably in weld if real stainless (316) if 304? pot luck. Install repaired or new tank. Foam or packing round.
Make up fresh lid for it as a mattress base, with hinges? to hold.
Have fun hey. Boats are like having a horse. something every day.

 

[Akestor]

The leak stopped as I was gradually emptying the tank until it stopped. So the hole is very close to the water level but I can't know where. It's interesting that while it doesn't leak from the top of the tank, it looks like it is the most corroded area, while the bottom seam of the tank looks in excellent condition. I guess permanent water evaporation on the top is more corrosive than the water itself. OR they made a cheap 304 seam on the top and a good 316 on the bottom...

 

[Tranona]

That was the same as my tank I described above. It only became apparent when the tank was filled to the brim and the boat experienced "bouncy" weather. The failed weld was near the top of a vertical seam. It may well have been like that for years a we tended to use the aft tank only. Inspection showed that there were other sections of vertical seams where the weld was showing signs of corrosion. All the suspect areas were repaired, brackets welded on for more secure attachment and 2 inspection hatches fitted to the top then pressure tested. Cost around one third of a new tank.

 

[Akestor]

Baffle internal plates. No internal tank poss without removal. Drill a few small pilot holes On each side of top of glass. Find ends of tank. Jigsaw and vac cleaner for dust.
Take out tank. Probably in weld if real stainless (316) if 304? pot luck. Install repaired or new tank. Foam or packing round.
Make up fresh lid for it as a mattress base, with hinges? to hold.
Have fun hey. Boats are like having a horse. something every day.

I am definitely having lots of fun the last 7 years with really wild projects and rebuilds on the boat but currently entering a stage in my life where time for such projects becoming limited...You know life changes etc. Well, I ll see, it might be my last big project lol (hopefully). Thank for feedback!