Flexible water tanks

[spark]

Does anyone have any experience - good or bad - of using these, especially the Plastimo ones?

Can they be partially filled so as to fit in awkward locations?

 

[paulrossall]

I replaced 2 old flexible bags with Plastimo ones 2 years ago. I find them excellent. Yes you can part fill them. Mine are constrained in a small area so they do not move about, otherwise I would strap them in place as you do not want them to move as the boat heels. Bought them at boat jumbles, don't pay Plastimo list prices, unless you are loaded.

 

[longjohnsilver]

I have a Vetus one, good quality but make sure you re-tighten the fittings after a few months - I didn't and found about 10 gallons of fresh water in my bilges!!

 

[tome]

Vetus tanks are supplied with inlet/outlet fittings and a template to cut the holes. The template hole is too big, which allows the fittings to wander under pressure.

Plastimo ones are supplied with fittings in place and far superior IMHO.

 

[extravert]

I've had one split at 13 years old. Only then did I find out that the waterproof bit was a removable liner that could be replaced. Perhaps the liner should be replaced every 10 years. At least when one does die it's damp but not a disaster or dangerous like diesel would be (any more 'd' words to go in there?) They seem like a good idea to me.

 

[bedouin]

Yes they can be fitted into awkward spaces - but let me give you a cautionary tale.

A friend of mine upgraded his water supply by fitting two flexible tanks, one under each of the two saloon berths, connected with a Y-piece, and then screwed down the locker lids. That was fine in the marina, but as soon as the boat heeled over the water in the windward tank tried to run down into the leeward, and blew the top off.

I would recommend individual valves on each tank for a number of reasons, not least this one

 

[spark]

Cautionary tale heeded. I intend to isolate each tank anyway, probably for the same reasons that you don't mention.

Thanks to all.
I think I'll get the Plastimo ones and line the space with something nice and smooth so that they don't rub on any hull fastenings. They'll make the tankage problem much easier to solve than going rigid. My worry was that they wouldn't last.

 

[colin_jones]

We have had Vetus flexible water tanks for about 10 years and they have been fine. There are possibly others as good.

Some suggestions are
Put something like carpet underlay (rubbery back) under the tank and even up the sides and overlap the top. It stops chafe and soaks up any odd drops of water.

Put some light plywood baffles into the locker so that the full tank cannot slide around.

Beware tanks with fillers already in situ because they might not line up with your best position and route for running inlet and outlet pipes, especially as the top (inlet) pipe might need to be very close to a filler pipe from outside the boat in order to let the tank fill to maximum capacity. This might only be a short length of stiff pipe. On some boats there is not much room for play here.

If you choose Vetus, begin all holes with a small 'pilot' hole and then enlarge it bit by bit. Fiddly and much bettr done in warm air, but worth doing.

We have had no pollution or bad taste problems, but we remove the tanks each spring and clean them out with Miltons baby lotion.

 

[Trevethan]

just bought a pair of 200 litre plastimos. quality seems excellent.. very robust and nice wide filler inlets.

I want to join the outlets of the tanks using a y piece, but will incorporate non return valves (and a shutoff) on each outlet hose to stop problems and let me isolate the tanks in case of problems.

Regarding inlet, I only have one filler cap on deck, so will probably have to employ a y connector and 2 non return valves to allow me to fill easily too I guess.

regards,

Nick

 

[gtmoore]

I have a similar setup but decided that running that big (38mm?) pipe over the saloon roof to fill the second tank was going to be difficult. Choices were two fillers on deck or blank off the filler on the second tank and let it fill from the first. I'm trying the latter for the moment. Tank filling means filling one tank then letting the water equalise (slow through 12mm pipe) before topping up the tank again and so on. For me it's not too much of a problem because I don't have a great use for the water at the moment (no shower etc although I'm piping in freshwater to the heads inlet to keep it all smelling nice!).

Reading Bedouin's warning earlier has made me question the method I've used for blanking the second tank filler and I now intend to fit some valves and use each tank independantly

Gavin

 

[Guest]

Re: Durability

I agree with the general concensus. My first Plastimo tank lasted 10-12 years. It replaced the original galvanised tank which had to be cut into small pieces with a grinder before it could be removed.
Just make sure you line the compartment with non-absorbent foam sheeting or similar. Carpetting would do the job, but it can smart to pong if it gets wet.