WATER TANK PLASTIC OR STAINLESS STEEL THE BIG QUESTION

[sailingrbg]

I am in the process of changing my 25 year old steel water tank which has quite bad corrosion internally and am wondering of the merits of stainless steel verses rigid plastic. My Port side water tank was replaced by the previous owner a few years ago but has a taint to the water taste. (Could be down to the pipes?)
To this end I am considering stainless steel for the starboard tank but at an approx cost of £500-600 think that this is quite expensive. The tank will need to be custom made to fit the shape of the hull and will only hold about 11 gallons.
My main problem is that I a wondering if the welding of stainless steel tank will hold up over the years if it is subjected to continual movement on a mooring. Or whether there is some form of plastic tanks which will not taint the water.
If I bite the bullet and go for the expensive option of the stainless steel, can anyone suggestions of what thickness of stainless steel to go for

Any thoughts gratefully received

 

[Evadne]

I've got s/s water tanks, they did leak a while ago but one of the various goos that I put on seemed to fix it, for now. If they hadn't been such an integral part of the boat's structure, apparently, I'd have had them out and replaced them. The welds will always give up, eventually, IMO, so I would go for plastic every time. Taste can be fixed with puritabs and filters. Leaks are more of a problem.

 

[Dalliance]

Have you had a quote from TekTanks? They did a brilliant job for me two boats ago and, though expensive, were much cheaper than stainless and the custom fit was superb.

 

[Mirelle]

I've got stainless tanks, fitted 1995, still fine. I'm not expecting any trouble from them. They replaced galvanised ones.

 

[qetoo]

My primary water tank is 65 gallon aluminum. It's been in the boat since 1973 and still holds water. I guess I don't see any advantage to stainless steel considering the high cost.

 

[Talbot]

Must be deja-vue could have sworn that I had just responded to this thread.

 

[Signed Out]

[ QUOTE ]
My primary water tank is 65 gallon aluminum. It's been in the boat since 1973 and still holds water. I guess I don't see any advantage to stainless steel considering the high cost.

[/ QUOTE ]

I recall hearing that aluminium contributes to Alzheimers. Although I confess I cook with pans made of it.
(How's that for a bit of web scaremongering?).

 

[TigaWave]

The plastic tank circa 1991, was good in my boat, no smells or tastes but we did have an inline filter, we had aft stainless...(very noisy to sleep over) and for'd plastic, surrounded by expanded foam so there was no movement.

I have expereince of the smells/tastes coming from the hose some people have used to fill their tank with. Some garden hoses don't seem to be the right plastic for drinking water (not surprising really) and leave a smell even though they are only used for filling.

 

[vyv_cox]

If you decide on stainless steel, accept ONLY AISI 316L with appropriate filler rods. 'Normal' 316 contains a small amount of carbon that will preferentially form chromium carbides in the welded region. This ties up chromium from the alloy and a condition known as 'knife line corrosion' will occur where the chromium content is reduced. The welding grades of stainless and filler contain traces of titanium and other metals that will preferentially form carbides, reducing the likelihood of this problem. Given the above your tanks should last indfinitely.

Having said all that, personally I would only have plastic tanks unless the economics are ridiculous.