Help with water tanks

[gtmoore]

Does anyone have any experience with fitting flexible water tanks? My boat has a 20 gallon tank under both port and starboard berths. They are both in a bit of a state with cracks and blisters in the tank surfaces so I'd like to put some of those nice liners in I've seen. Problem is that all the reasonable priced standard sized ones are over 70cm wide and my tanks are 36cm wide. To get custom made ones costs over £200 each! Bearing in mind the liner will be totally enclosed and the filling is via gravity from the deck filler, is it a definite no-no to fit a flexible tank that is too wide?

Thanks

Gavin

 

[pvb]

I\'ve used Plastimo flexible tanks

Installed a Plastimo flexible tank some years ago. The inner bladder failed after a couple of years, but the replacement bladder is still fine after about 5 years.

Plastimo tanks are quoted as being 70cm wide, but remember that's when they're empty (ie when they're flat). As they fill with water, they become more cylindrical and consequently narrower. You'd probably be able to fit something like that in place of your old tanks.

Failing that, if there's reasonable access to your old tanks, why not epoxy the inside surfaces?

 

[gtmoore]

Re: I\'ve used Plastimo flexible tanks

Thanks - I was hoping it was the case that it would become narrower when filled.

One of the tanks was leaking when we bought the boat and had been capped off. When we opened it up to take a look it was horrible! The working tank was the same. After a good cleanup, the only thing remaining were the blisters but there were loads of them and popping them released the usual fluid. I don't think the tank lids had ever been removed (we had to cut them off) so what with having to now make watertight lids AND having the blisters I thought a tank liner might be better. The Plastimo ones seem quite cheap but the size was the problem.

I don't suppose you know what happens with the vent pipe? We have one on each tank - are these not required with flexible tanks?

Thanks again for your help

 

[Strathglass]

Re:vents

Not required with flex tanks. Make sure that the lid on your original tanks are secured down to hold the new tanks in place.
Iain

 

[paulrossall]

The gap for my flexible tank is only 30cm (that is 1 foot isnt it?) and I used Plastimo ones that should have been too big and they have worked very well. Also no need for that vents business as when the water goes down the bag shrinks. It is a much more hygenic arrangement than fixed tanks.

 

[gtmoore]

Thanks to everyone for their advice - I've ordered the Plastimo tanks and keeping my fingers crossed!

Gavin

 

[LeonF]

I have the same situation on my boat- the water was foul and I opened the lids to clean the GRP tanks to find that the rampant osmosis had led a previous owner to fit flexi tanks-albeit they are fitted ones in black polyester. They retained the breather tubes which are led to the cockpit. I unclipped the piping and took them home, phoned the maker who advised against the popular suggestion of Milton, and i followed the instructions on the tanks of using non-biological detergent. Copious scrubbing-rubbing the skin against itself and the emergence of brown slime and they are back in the boat and the water seems fresh and clear. The important thing was to screw the original lids down well as the expansion of the tank can force them off. Hope this is of some use.

L.A.R.Ferguson