Water tank - Stainless or Plastic

[Alpha22]

It looks like I may need a new fresh water tank. The current stainless offering has started to crack right on the welds.

There is nothing special about the tank or installation. It is a rectangular tank with top fill, bottom exit. It drops straight into position under the cockpit floor.

The big question. Is there any advantage to stainless steel over plastic??

 

[prv]

Don't know if a stainless one would be better, but I certainly have no problem with our moulded plastic tank after 16 years, mostly of heavy charter use before we bought the boat. I dose it with cleaning powder each spring as a precaution, though I had a taste before doing so this year and it seemed fine anyway. We drink from the tank (as in, plain glass of water, not just as tea or squash) and it tastes no different to the Southampton tap water we fill up with.

Pete

 

[PetiteFleur]

Plastic is better, no welds to leak, if translucent you can see level but only made in 'standard' sizes. Off the shelf tanks by Vetus, Plastimo, Cak Tanks and possibly TekTanks. Cak Tanks usually for caravans and motorhomes but you may find one to suit. TekTanks will make one to your exact size but expensive. Stainless tanks any size but expensive(and can leak....)
Good Luck

 

[Tranona]

Tek Tanks also do standard size moulded tanks. Roughly half the price of custom made fabricated tanks.

 

[oldgit]

Have look on ebay.Couple of the major makers advertise their wares on there.Even if you get a custom plastic tank made,it costs a whole lot less than heavy old metal jobby.
It will also turn up before the bloke knocking up your stainless one has retrieved your request for him to phone you,from the bottom of a pile of orders he should have started summer 2013.

http://www.ebay.co.uk/itm/caravan-C...376?pt=LH_DefaultDomain_3&hash=item1c4e079658

 

[arawa]

Plastic is better, no welds to leak, if translucent you can see level but only made in 'standard' sizes. Off the shelf tanks by Vetus, Plastimo, Cak Tanks and possibly TekTanks. Cak Tanks usually for caravans and motorhomes but you may find one to suit. TekTanks will make one to your exact size but expensive. Stainless tanks any size but expensive(and can leak....)
Good Luck

Just filled my 5-year old plastic tank (Vetus 88L) in preparation for boat launch to find it is leaking. As the boat seems to have been built around the tank I have not yet been able to find the exact source but I am pretty sure it is the tank and not any of the connections.

 

[Alpha22]

I'm particularly interested to know of any advantages and disadvantages of Stainless steel or plastic.

If money was no object, which would you choose and why?

 

[[70521]]

If money was no object, which would you choose and why?

Plastic, weight.

 

[Tranona]

I'm particularly interested to know of any advantages and disadvantages of Stainless steel or plastic.

If money was no object, which would you choose and why?

Plastic every time. The fact that you need to replace your SS tank explains all. They can be good, but prone to corrosion in welds. Difficult to spot until it happens.

 

[medium]

I don't know where that comparison. but in my opinion plastic is better

 

[LittleSister]

My stainless tanks (2 x water, 1 x diesel) are doing fine after 30 years use. They don't seem particularly heavy. I can't imagine a plastic one would be much lighter (the material would probably need to be thicker), and in any case the tanks' weight is almost negligible compared to that of their contents.

I have little experience of plastic tanks, so I'm not in a position to offer a comparative opinion.

 

[prv]

I can't imagine a plastic one would be much lighter (the material would probably need to be thicker), and in any case the tanks' weight is almost negligible compared to that of their contents.

The fabricated plastic tanks are quite thick, I think 10mm is Tek-Tanks' standard, but the roto-moulded ones are far thinner and must be a fair bit lighter than stainless. However, I agree that it doesn't really matter given the weight of the contents.

I have moulded plastic water and stainless diesel; the previous boat had flexible bag water and fabricated plastic diesel. The flexible bag tainted the water and was a pain to fill, but the rigid tanks in all three materials were and are entirely satisfactory.

Pete

 

[Martin Rye]

http://www.tek-tanks.com/2009/10/advantages-and-disadvantages/

 

[ronsurf]

Can't you just get the old one welded? It's a lot easier to fit something back where it came from.

 

[vyv_cox]

My plastic 60 litre holding tank is a lot heavier than my 100 litre stainless diesel tank.

Most of the bad welds in older tanks are due to poor materials selection. Far too many welders used the cheapest sheet metal available. If a stainless tank is made correctly by someone who knows what they are doing it will last indefinitely.

 

[Momac]

Plastic has to be the better material.
Can't imagine why boat builders fit stainless tanks for fresh water and especially not for holding tanks .

 

[Grumpybear]

Slight thread drift, but:

The 175 litre forward water tank in our Jeanneau is polyethylene, and was installed before they put the deck on - I would have had to cut it up to get it out of the boat or a replacement in. After about ten years' service it developed a leak, which I eventually traced to one of the integral baffles in the bottom of the tank. It appears that when the tank was formed, the material was thinned excessively at one top corner of one baffle, and suddenly gave way. I eventually repaired it at the second attempt with some of that eye wateringly expensive PE adhesive used as a putty, after much filling and draining and turning it upside down in the core peak.

 

[Alpha22]

In the end I took the stainless one out and took it to a specialist stainless sheet metal guy on a local industrial estate.... he ground out all the old welds.... poor quality filler rod by all accounts. He re-welded the whole tank, dye tested all the welds with penetrating dye. 12 month warranty.... all for £60!!!! No contest!!!!

 

[Boathook]

Plastic has to be the better material.
Can't imagine why boat builders fit stainless tanks for fresh water and especially not for holding tanks .

My boat has s/s water tanks. Fabricated in the mid 70's and still seem sound. If they leaked I would get them repaired rather than replace.

 

[Boo2]

The big question. Is there any advantage to stainless steel over plastic??

Yes, the material used in a stainless steel tank is a lot thinner than a plastic tank and it can make a surprising difference to the capacity you can fit in a given space. In all other respects IMHO a plastic tank is better.

Boo2