Seriously?! Water tank leaking!

[Cardo]

So, as we're now on our final stretch to getting the boat ready for cruising this season, I have discovered the main fresh water tank has a leak (Or, actually, a few of them). Buggerit! The tank, as far as I can tell, is stainless steel, but it looks like it is leaking from small holes along one of the edges where it seems the welding has rusted?

I'm hoping the tank will come out without too much swearing, but what then? I'm hoping I can take it to a steel chap I know and get him to clean up the weld. Is this a practical solution?

Or is something more severe and time consuming required?

 

[Alpha22]

Mine went on the weld... work hardening from flexing every time it was filled and emptied..... My local stainless man welded it.... sold the boat 6 months later....

 

[NornaBiron]

So, as we're now on our final stretch to getting the boat ready for cruising this season, I have discovered the main fresh water tank has a leak (Or, actually, a few of them). Buggerit! The tank, as far as I can tell, is stainless steel, but it looks like it is leaking from small holes along one of the edges where it seems the welding has rusted?

I'm hoping the tank will come out without too much swearing, but what then? I'm hoping I can take it to a steel chap I know and get him to clean up the weld. Is this a practical solution?

Or is something more severe and time consuming required?

From personal experience it is a waste of time getting it repaired. We had ours done 4 years ago and within 2 years other areas were leaking. Maybe it's time to bite the bullet and have it replaced.

 

[blackbeard]

I'm fortunate that I haven't, so far, had salt water sloshing about in the bottom of the boat, but fresh water in several occasions. The fresh water system seems to cause even more trouble than its house equivalent.
For what it's worth, a flexible tank might solve your problems fairly easily and cheaply for a while, but even these can fail after a few years. Might be worth a try though

 

[rotrax]

Hi Cardo, in the short term-which may turn out longer than you hope or expect- if you can see the leaks, drain the tank, clean,rough up the leaking areas and try two pack epoxy.

As long as its not leaking where you cant reach, it might be worth a punt.

Good Luck.

 

[Tranona]

Just had one of my tanks repaired. Whether it is feasible or worth it you will only find out when you get it out. Almost certainly on a weld line. Mine was plated with an L shaped plate over the whole seam. Not leaking yet!

 

[Cardo]

Thanks for all the replies. Whilst a new tank would be the best solution, we don't really have the time, or the inclination to do that at this time if we don't need to. I'll get the steel man to tidy up the dodgy area, which will hopefully see us through until at least after we return to the UK.

 

[TradewindSailor]

I had one tank 'repaired'. Soon after more leaks appeared. I repaired those with epoxy and pressure tested. I eventually found over 50 small pinholes and chucked the tank away.

The problem with flexible tanks is that they need to be properly secured in a chafe free environment ..... not that easy!

It shouldn't take long to get a polypropylene tank made.

 

[Tranona]

Thanks for all the replies. Whilst a new tank would be the best solution, we don't really have the time, or the inclination to do that at this time if we don't need to. I'll get the steel man to tidy up the dodgy area, which will hopefully see us through until at least after we return to the UK.

If you do find it is beyond repair there is a German guy in Gouvia who makes excellent plastic tanks. He made my holding tank and it is as good as Tek Tanks in UK. Let me know and I will find his contact details if you need it.

 

[coopec]

Two pot epoxy is not recommended for amateur use in potable water tanks.

QUOTE Considerations for potable water tanks
We have adopted the broad policy of not recommending epoxy for drinking water tanks because of regulatory and safety issues. The potential problems outweigh the benefits. To date, none of Gougeon Brothers' epoxies meet FDA regulations or any other drinking water certified approval. The major long-term concern with any plastic water tank is extractives leaching out in the water. Off-ratio, poorly cured epoxy can release extractives, as noted above. In the fabrication of water tanks and food handling equipment, the successful use of epoxy requires thorough mixing and adequate elevated temperature post-cure to assure the maximum cross-linking and cure of the polymer. These process controls are not always possible with the home-built tank. Unfortunately, neither Gougeon Brothers, Inc. nor any certification agency can verify the level of quality control exercised in the fabrication of the tank.UNQUOTE (Gougeon Brothers)

http://www.westsystem.com/ss/wood-epoxy-composite-tank-guidelines/

Why not use a water based bitumen which is approved for use for potable water tanks by the authorities??

https://www.youtube.com/watch?v=xn9xmKsPsW4

https://www.youtube.com/results?search_query=Water+based+bitumen+potable+water&sm=12

 

[cagey]

Sorry to hear about leak, agree with almost everyone, had same prob with steel water and fuel tanks and tried the cheap route but it was an expensive exercise. Replaced with plastic,and although not without its problems has proved to be effective . Check out ASAP site as their stock items could be a cheap result
K

 

[Sandy]

How about some of this stuff?

http://www.amazon.co.uk/Plumbers-Mate-Quick-Repair-Putty/dp/B004WDM8J2

 

[rotrax]

Two pot epoxy is not recommended for amateur use in potable water tanks.

QUOTE Considerations for potable water tanks
We have adopted the broad policy of not recommending epoxy for drinking water tanks because of regulatory and safety issues. The potential problems outweigh the benefits. To date, none of Gougeon Brothers' epoxies meet FDA regulations or any other drinking water certified approval. The major long-term concern with any plastic water tank is extractives leaching out in the water. Off-ratio, poorly cured epoxy can release extractives, as noted above. In the fabrication of water tanks and food handling equipment, the successful use of epoxy requires thorough mixing and adequate elevated temperature post-cure to assure the maximum cross-linking and cure of the polymer. These process controls are not always possible with the home-built tank. Unfortunately, neither Gougeon Brothers, Inc. nor any certification agency can verify the level of quality control exercised in the fabrication of the tank.UNQUOTE (Gougeon Brothers)

http://www.westsystem.com/ss/wood-epoxy-composite-tank-guidelines/

Why not use a water based bitumen which is approved for use for potable water tanks by the authorities??

https://www.youtube.com/watch?v=xn9xmKsPsW4

https://www.youtube.com/results?search_query=Water+based+bitumen+potable+water&sm=12

Your reply indicates covering the internal surfaces with a two pack epoxy. This appears not to be a good idea, due to the large surface area inside the tank.

My post to Cardo, however, advised him to cover pinholes externaly with two pack.

As a temporary repair, this action is not likely to be hazardous to health-especially if, as on our boat, bottled water is used for drinking.

 

[Cardo]

Replaced with plastic,and although not without its problems has proved to be effective .

Could you state what the problems are with a plastic tank?

Now that I've wrestled the tank out of the boat and filled it up with a bit of water, it has become apparent that there are a _lot_ of pinhole leaks, although all along the welds.
I'm trying to decide whether to bother getting this fixed, or get a new tank made up. The main issue is time, we're meant to be heading off in less than a week! (Though we can start off with just our second, smaller tank and cruise with that for the first couple of weeks).

 

[vyv_cox]

The cause of your problem is almost certainly a phenomenon known as sensitisation, caused by selecting an 'ordinary' stainless steel, e.g.316 rather than a low carbon one, for example 316L. Rewelding will not give you a permanent repair because the fundamental problem is the tank material. Even welding L-shaped corners is not going to solve it, for the same reason. I think the external epoxy patching is likely to be the best option and, quite timely, an article in the current PBO suggests the adhesion should be perfectly OK. Abrading in the normal way before applying the epoxy should give acceptable results.

 

[Cariadco]

Top Tanks

Could you state what the problems are with a plastic tank?

Now that I've wrestled the tank out of the boat and filled it up with a bit of water, it has become apparent that there are a _lot_ of pinhole leaks, although all along the welds.
I'm trying to decide whether to bother getting this fixed, or get a new tank made up. The main issue is time, we're meant to be heading off in less than a week! (Though we can start off with just our second, smaller tank and cruise with that for the first couple of weeks).

As per earlier post, go find the German guy. He drives round in a white 4WD with 'Top Tanks' notice on the roof. I can't remember his name but he replaced my tanks with plastic ones. Bye Bye problems....!
Ok, he wasn't cheep but he did a superb job. He had to dismantle most of my galley and worktops, and you'd never know. He used to be a Kitchen fitter/carpenter, years ago, so stuff like that he really good at.
He hang's around Klaus' office, opposite Harri's Tavern.
I fully recommend him.
Regards,

 

[charles_reed]

2nd Vyv's opinion as to the reason and "best" short-term solution.
My tank is part of the boat's structure and in GRP - a friend with a similar boat, finally sold it, after 2 years of "hunting the leak".
I mention this to re-assure you that your luck is in.

 

[Cardo]

As an update to the thread, I've ended up engaging Loupe (or Wolfgang, the Top Tanks guy) and arranged for him to make a plastic copy of my stainless tank. He's waiting on new materials from Germany, but hopefully will be able to get it done within 3 weeks or so.
Not cheap, but I figure it'll be another problem properly sorted.