Flexible Water Tank?

[Dave Wood]

On my '98 35 ft Beneteau the PO put in a bow thruster which I love when I am docking. But it was installed in what had been the forward water tank. Now we are down to 50% of original fresh water storage and the boat rides light in the bow. The orignal deck fitting for the forward water tank is still there. Likewise the filler hose and overflow which have been cut off about 2 ft below deck and sealed with wooden plugs and glue. The original fresh water supply from the forward tank to the manifold is still there also, but sealed.

Question #1: would it be advisable to install a flexible water tank of some sort in the 1ft X 1.5ft X 5ft empty cavity remaining aft of the thruster tunnel and reconnect it to the original hoses?

Question #2: if yes, what make/brand/type of flexible tank would be best for this application, and what precautions should be taken?

Thanks for any advice you can give.

[Zephyr's Aura]

I have the plastimo and have had very good luck with it. My only complaint is that it is hard to clean inside. Have to push a sponge through the water inlet and move it around inside the tank. I clean it once a year so it's not that big of a deal. Flush with white vinegar every three months or so between washing.

Tim

[Aqua Vitae]

I have read that flexible water tanks should be installed securely in their own "berth." This consists of foam (high density, I believe) of around 1" thick cushioning between the water bladder and the hull. It should also be secured with pad eyes and line run to the grommets they usually have on each corner. This will make it less likely to roll or slide which would break it of course. If you want to check it out yourself, I think it's in Nigel Calder's Electrical and Mechanical Manual.

[speedoo]

Why not install a plastic tank from these folks:

Ronco Plastics - www.ronco-plastics.com

If one of their tanks will fit, it might be your best option and they are not expensive.

Or if they don't have one that will fit, you could have a stainless tank fabricated. Probably expensive, however.

[Randyonr3]

My FIRST 42 came with flexable tanks.. when replacing I used the Plastimo units..
No prep, no fuss, no muss, roll em out in the compartment, plug in the hoses and fill them up.. the tanks have a canvas bag the plastic liner is cradeled in...
I've got two of the 60 gallon tanks in the center of the boat under the seats and the large tri-angular unit up forward... In the forward section I did attach a belt system to hold the tank in place.. kinda like seat belts for the tank..
I've been using them for 5 years now, we live on the boat so they get a-lot of use..

[little boat]

I've got two nautas and love them.
Re cleaning them out: When they are empty, just remove filler hose; fill with water with a splash of vinegar or bleach; (if in the boatyard, I let them sit a few days), swish/squish alot and let water run through for a while; water's always been clean.
No special installation on mine; just tied through eyelets to something on one that's on a tilt; the one in the bilge just sits there.
I had to throw away a vetus one time, lousy construction and leaked after only a few months.
On sale now at defender: Water Tanks on Sale

[Pblais]

The size you mention is 7.5 cubic feet or about 56 gallons and 448 pounds. Assume what you could net out of the space is less but still a nice sized water tank. 30 gallons would make it very tempting to me so I think it's worth looking further. Securing it will be the harder part of the job. You can't have a 448 pound bag of water getting loose. The more you can contain the flexible tank the less you need to worry about it getting loose, but the shifting could easly rip the hose connections.

Often the bladder tanks are made to lie flat so the up down motion minimizes the forces.

[S/V Antares]

Check out Turtle pac (Oz) The are the only ones that have enough fastening points. Real strong stuff.

[creighton]

My Pastimo flexible water tank has sprung a leak along one of its seams. Any suggestions on how or what to patch it with ?

[S/V Antares]

Creighton, Most tanks are heat welded howvever it is likely PVC coated fabric. Use the same goober (Glue) as used in PVC inflatables. You will need to be careful not to get any inside or you will taste it. Coat the area on the seam. Overlay with a patch if needed and clamp it between to pieces of wood.

[GordMay]

WELCOME Aboard, creighton !!!

I’m not certain that a simple PVC repair patch will be effective on a Plastimo flexible water tank.
The Plastimo water tanks consist of a welded PVC water chamber (inner bladder) inside an outer nylon envelope. They do sell replacement bladders.

Contact:
Platimo (USA) Dealers: Plastimo USA

Or:
Navimo USA, Inc.
7455 16th Street East, Suite 107, Sarasota, FL 34243
Toll-free: 866.383.1888
Toll-free fax: 866.214.1400

[hellosailor]

Flexible tanks are also called "blivets" in the military and elsewhere. The biggest problems with using one for water are cleaning it, as noted, and puncturing or chafing it. If you make sure it is installed against a smooth surface (rubber floor matting, carpet or carpet tiles, vinyl runners, etc.) so it isn't damaged by raw wood, fiberglass, or other sharps, it should last very nicely. I wouldn't hesitate to use one.

[getlostonpurpose]

if you go to lowes or home depot flooring section, they sell foam/rubber type interlocking mats for home gyms and play areas. i lined the insides of both my old fiberglass tanks with that stuff and put in the plastimos. be careful that the space is large enough for the tank or it will put too much pressure on the seams when it's full.