Flexible water tanks

[tikvah59]

The water tank under the V-berth in my Triton had not been used in some time, so I cut an inspection hole to check it out. After removing the baffle, which had become disconnected, I found a bunch of mildew. Rather than scrubbing then painting it with some fancy FDA-approved paint, I thought I might install a flexible water tank. Anybody have any experience with these?

I'm imagining cutting a large hole in the top of the water tank, and putting the flexible one right in there. Plastimo makes a 31.5 gallon model ($120 at Defender, under $100 elsewhere) and Vetus makes a 26.5 gal version ($199 at Defender). Your thoughts?

Thanks

[A30_John]

I've gong through a similar process of evaluation as you, and I'm thinking of doing the same thing. I've heard that chafe can be a problem with flexible tanks, and it's important to prepare the mounting area so it's free of sharp corners, etc. It's also important to secure them firmly, so adequate tie down points should be a key consideration.

Please keep us updated with your project.

John

[bcooke]

Sounds like a pretty good idea to me .... now.

I don't have that much experience with flexible tanks but I think chafing and funky taste/dirt in the tanks are their downfall.

From a cost/benefit point of view I would say your idea will definitely give you the best bang for the buck. If the tanks have to be replaced every 5-10 years it will take a long time to equal the cost of the tanks that are being welded up for me even as I type this.

-Britton

[CharlieJ]

JUST today finished installing one under Tehani's cockpit. A Vetus 70 liter tank. Had a 22 gallon one in my trimaran- used it for all the time we had the boat with absolutely NO problems. Neat thing is you don't need a vent, so no tubes, etc to leak.

If you are putting it INSIDE an existing tank you shouldn't even need to worry about tying it down.

[Rachel]

I've never used a flexible tank and I'm curious about something: Say, for example the tank is in a confined space - like a tight bilge area or an old tank. I can see where it wouldn't move around, slosh, or chafe when it was full, but wouldn't it tend to do so when it was half full or a bit less? Or?

--- R.

[Figment]

My only experience is with use as trim ballast.... +/-40 gallons in a starboard compartment to offset the considerable weight of a late-1980's inverter mounted to the portside bulkhead.

We wondered what was up with the seemingly unnecessary water capacity, until we removed it and noticed that the boat mysteriiously took on a 5degree list. We didn't learn the weight of the inverter until the following year when it crapped out. The 3/4" rope the installer left attached might have tipped us off, but we weren't thinking in that direction.

[tigerregis]

First post. I found one at BAM in Annapolis for $5. Installed it 4 years ago and it is perfect. I drink rum and water, so you should know that quality is very important. I think they are good for anything except waste.

[CharlieJ]

Couple of pics of Tehani's under cockpit tankage and anchor storage box. The tank is a 70 liter Vetus and is lashed to eye straps in each corner.

First- the full tank.



Then the floor goes over that, gets sealed and screwed down, then the anchor and rode is put in. I don't have a pic showing the cover over the anchor storage, but it forms the bottom of the cockpit

[tikvah59]

Charlie,

Thanks for the pictures! You're storing water in the Vetus tank, correct? Is there a reason you went with the Vetus rather than Plastimo or another brand?

Thanks,

[CharlieJ]

Yup- an EXCELLENT reason- A friend of mine over in Florida had it spare and gave it to me *grin*

And yes- it's for water. That effectively doubles our water capacity (to 140 liters). Now we're ready for much longer cruises- or much longer times out away from civilization.

[dasein668]

That effectively doubles our water capacity (to 140 liters).

That's about 37 gallons for us metrically challenged folks. 8-D

[A30_John]

Is there a reason you went with the Vetus rather than Plastimo or another brand?

I've been researching flexible tanks and have narrowed the selection down to Vetus or Nauta. I haven't been able to find much comparative information on them in terms of construction quality, reliability, etc. If anybody can help, I'd greatly appreciate it.

My research returned several results on the Vetus tanks and they were all positive. I was unable to find any commentary on the Nauta tanks. They look stronger/heavier in the pictures.