Flexible water tanks?

[Mike Keers]

Hey gang,
Couldn't turn up any hits with the search, so not sure if this has come up before.

Does anyone have any experience with flexible fresh water tanks? I'm looking for direct or anecdotal experience with the common brands,ie, Nauta, Plastimo, Vetus, etc.

I've got my Puffin 28 turned right-side up, and I'm starting on some of the interior structure, so systems designs are entering the picture. A fexible tank of about 35 gallons would be the best use of space (maximum volume)under the sole.

My only experience is with smaller camping bags, and it was not positive. In fairness, these were little more than very expensive HD Zip-loc bags inside an outer nylon protective bag. But noticing the disparity between prices of marine bags, and the variety of materials used has got me pondering and wondering.

[ 07-29-2002, 03:41 PM: Message edited by: Mike Keers ]

[Mike Keers]

Hey gang,
Couldn't turn up any hits with the search, so not sure if this has come up before.

Does anyone have any experience with flexible fresh water tanks? I'm looking for direct or anecdotal experience with the common brands,ie, Nauta, Plastimo, Vetus, etc.

I've got my Puffin 28 turned right-side up, and I'm starting on some of the interior structure, so systems designs are entering the picture. A fexible tank of about 35 gallons would be the best use of space (maximum volume)under the sole.

My only experience is with smaller camping bags, and it was not positive. In fairness, these were little more than very expensive HD Zip-loc bags inside an outer nylon protective bag. But noticing the disparity between prices of marine bags, and the variety of materials used has got me pondering and wondering.

[ 07-29-2002, 03:41 PM: Message edited by: Mike Keers ]

[Mike Keers]

Hey gang,
Couldn't turn up any hits with the search, so not sure if this has come up before.

Does anyone have any experience with flexible fresh water tanks? I'm looking for direct or anecdotal experience with the common brands,ie, Nauta, Plastimo, Vetus, etc.

I've got my Puffin 28 turned right-side up, and I'm starting on some of the interior structure, so systems designs are entering the picture. A fexible tank of about 35 gallons would be the best use of space (maximum volume)under the sole.

My only experience is with smaller camping bags, and it was not positive. In fairness, these were little more than very expensive HD Zip-loc bags inside an outer nylon protective bag. But noticing the disparity between prices of marine bags, and the variety of materials used has got me pondering and wondering.

[ 07-29-2002, 03:41 PM: Message edited by: Mike Keers ]

[Ed Nye]

Mike,
Opal has flexible tanks. Nauta for the holding tank and Vetus for the fresh water. Both a plumbed to the deck for filling or empting. My first observation is that I have never thought about them. In the winter I make sure they are empty and not on the planks. In the spring I flush the fresh tank with a little Clorox (some formula I got from someplace) and then don't think much about it again until winter.
Ed

[ 07-29-2002, 03:51 PM: Message edited by: Ed Nye ]

[Ed Nye]

Mike,
Opal has flexible tanks. Nauta for the holding tank and Vetus for the fresh water. Both a plumbed to the deck for filling or empting. My first observation is that I have never thought about them. In the winter I make sure they are empty and not on the planks. In the spring I flush the fresh tank with a little Clorox (some formula I got from someplace) and then don't think much about it again until winter.
Ed

[ 07-29-2002, 03:51 PM: Message edited by: Ed Nye ]

[Ed Nye]

Mike,
Opal has flexible tanks. Nauta for the holding tank and Vetus for the fresh water. Both a plumbed to the deck for filling or empting. My first observation is that I have never thought about them. In the winter I make sure they are empty and not on the planks. In the spring I flush the fresh tank with a little Clorox (some formula I got from someplace) and then don't think much about it again until winter.
Ed

[ 07-29-2002, 03:51 PM: Message edited by: Ed Nye ]

[paladin]

Boat sails....water (or other liquid sloshes) tank chafes through...mess in bilge...

[paladin]

Boat sails....water (or other liquid sloshes) tank chafes through...mess in bilge...

[paladin]

Boat sails....water (or other liquid sloshes) tank chafes through...mess in bilge...

[Ian McColgin]

Pal and Ed confirm what I've seen - done right they work, done wrong they don't. The only time I was building tanks into a boat and we thought of going flexable, by the time we were getting done, it was clear that the work to make a tank and the work to make a good place to put a flexable tank are about the same. Given that, it's hard to bother with the expense of the flexable unless, like for a holding tank, you want what amounts to a disposable liner. After a decade or so that might well justify the expense.

[Ian McColgin]

Pal and Ed confirm what I've seen - done right they work, done wrong they don't. The only time I was building tanks into a boat and we thought of going flexable, by the time we were getting done, it was clear that the work to make a tank and the work to make a good place to put a flexable tank are about the same. Given that, it's hard to bother with the expense of the flexable unless, like for a holding tank, you want what amounts to a disposable liner. After a decade or so that might well justify the expense.

[Ian McColgin]

Pal and Ed confirm what I've seen - done right they work, done wrong they don't. The only time I was building tanks into a boat and we thought of going flexable, by the time we were getting done, it was clear that the work to make a tank and the work to make a good place to put a flexable tank are about the same. Given that, it's hard to bother with the expense of the flexable unless, like for a holding tank, you want what amounts to a disposable liner. After a decade or so that might well justify the expense.

[Figment]

in my observation the primary application for a bladder tank is when you need more tankage, but can't or don't want to rip out the necessary interior elements to get a rigid tank into place. a 30gallon bladder rolled up fits through a pretty small opening, then just unrolls and fills..... no muss no fuss. but unless carefully protected against chafe, it won't last long.

worst application for a bladder tank ever: 34'sportfish, 40gallon bladder in the hanging locker to starboard to counterweigh the inverter mounted on the port bulkhead, both mounted 5 or 6' above the waterline. with the bladder empty the boat listed 7 degrees to port.

[ 07-29-2002, 05:20 PM: Message edited by: Sailortect ]

[Figment]

in my observation the primary application for a bladder tank is when you need more tankage, but can't or don't want to rip out the necessary interior elements to get a rigid tank into place. a 30gallon bladder rolled up fits through a pretty small opening, then just unrolls and fills..... no muss no fuss. but unless carefully protected against chafe, it won't last long.

worst application for a bladder tank ever: 34'sportfish, 40gallon bladder in the hanging locker to starboard to counterweigh the inverter mounted on the port bulkhead, both mounted 5 or 6' above the waterline. with the bladder empty the boat listed 7 degrees to port.

[ 07-29-2002, 05:20 PM: Message edited by: Sailortect ]

[Figment]

in my observation the primary application for a bladder tank is when you need more tankage, but can't or don't want to rip out the necessary interior elements to get a rigid tank into place. a 30gallon bladder rolled up fits through a pretty small opening, then just unrolls and fills..... no muss no fuss. but unless carefully protected against chafe, it won't last long.

worst application for a bladder tank ever: 34'sportfish, 40gallon bladder in the hanging locker to starboard to counterweigh the inverter mounted on the port bulkhead, both mounted 5 or 6' above the waterline. with the bladder empty the boat listed 7 degrees to port.

[ 07-29-2002, 05:20 PM: Message edited by: Sailortect ]

[Charlie J]

I used a 25 gallon one - Vetus I think- in the bilge of my trimaran for three years and was happy with it. I couldn't tell you how long it lasted after I sold the boat.
It fit nicely into an odd space that a built in tank would have been a pain to put into.

[Charlie J]

I used a 25 gallon one - Vetus I think- in the bilge of my trimaran for three years and was happy with it. I couldn't tell you how long it lasted after I sold the boat.
It fit nicely into an odd space that a built in tank would have been a pain to put into.

[Charlie J]

I used a 25 gallon one - Vetus I think- in the bilge of my trimaran for three years and was happy with it. I couldn't tell you how long it lasted after I sold the boat.
It fit nicely into an odd space that a built in tank would have been a pain to put into.

[Dale Genther]

I had Vetus water tanks and holding tank in a 35 ft sailboat I once owned. They worked fine, but I was never totally comfortable with them.

[Dale Genther]

I had Vetus water tanks and holding tank in a 35 ft sailboat I once owned. They worked fine, but I was never totally comfortable with them.

[Dale Genther]

I had Vetus water tanks and holding tank in a 35 ft sailboat I once owned. They worked fine, but I was never totally comfortable with them.

[John B]

I have a plastimo tank. didn't taste very good for the first year or so. Still, I like the way the load is spread. I like the way I can pull it out super easy and get to the hull. I like the flexibility you might say.LOL.( cracks up laughing at poor pun.)( you are a sick sick man JB)

[John B]

I have a plastimo tank. didn't taste very good for the first year or so. Still, I like the way the load is spread. I like the way I can pull it out super easy and get to the hull. I like the flexibility you might say.LOL.( cracks up laughing at poor pun.)( you are a sick sick man JB)

[John B]

I have a plastimo tank. didn't taste very good for the first year or so. Still, I like the way the load is spread. I like the way I can pull it out super easy and get to the hull. I like the flexibility you might say.LOL.( cracks up laughing at poor pun.)( you are a sick sick man JB)

[mmd]

I designed a 36-ft alum. commuter yacht for a client who specified bladder tanks for fresh water and sewage. I believe that the builder used Vetus. I very carefully specified how the tank was to be cradled in the bilge to eliminate sharp edges and chafe points, and the owner has reported nothing but satisfaction in the three seasons that he has been using the boat. He summers on his island in Chester and uses the planing boat every day at 15 - 20 knots in up to 3 ft chop, so the bags have had every opportunity to fail.

[mmd]

I designed a 36-ft alum. commuter yacht for a client who specified bladder tanks for fresh water and sewage. I believe that the builder used Vetus. I very carefully specified how the tank was to be cradled in the bilge to eliminate sharp edges and chafe points, and the owner has reported nothing but satisfaction in the three seasons that he has been using the boat. He summers on his island in Chester and uses the planing boat every day at 15 - 20 knots in up to 3 ft chop, so the bags have had every opportunity to fail.

[mmd]

I designed a 36-ft alum. commuter yacht for a client who specified bladder tanks for fresh water and sewage. I believe that the builder used Vetus. I very carefully specified how the tank was to be cradled in the bilge to eliminate sharp edges and chafe points, and the owner has reported nothing but satisfaction in the three seasons that he has been using the boat. He summers on his island in Chester and uses the planing boat every day at 15 - 20 knots in up to 3 ft chop, so the bags have had every opportunity to fail.

[Mike Keers]

Well, just want to thank you guys for the responses. I also talked with a coupla friends with some experience, and I'm forming the conclusion that the tanks themselves are probably more or less reliable (seen a few plastic ones fail in my time too), and the key, as mentioned a few times above, is in the installation, to reduce movement and chafe. Also, a guy who's used them successfully for years says not overfilling them all the time seems to help.

So, good mounting, preventing chafe, proper filling, and it seems they can be as reliable as a plastic drop-in tank, altho perhaps with a limted (ten-year?) life. One advantage would be the ease of replacement if and when they do fail.

The jury is still out on this one. Another option I have is to use rigid plastic tanks and simply use two smaller ones located in other locations.

Now, over the years I have made a few tanks out of ply and poxy, including a fresh water tank of about 28 gallons, and a 25 gallon holding tank. I've never experienced any problems of leakage (and I plan to build in two 45 gallon diesel tanks on this boat). But I did notice an off-odor or taste to the water in my last boat after sitting in the tank for about six months down in tropical Mexico. It was more a mild chemical-type taste than bacterial, but who knows? Simply draining the tank and replacing the water cured that, but I've always wondered if I was drinking trace amounts of Bad Things. I used a 3:1 tank coating type googe for the lining. I've heard there are actually FDA approved epoxies for drinking water, but have no direct knowledge. If I could reconcile this concern, I'd simply make ply and 'poxy tanks. Comments?

Thanks again to all for the thoughful advice and observations all around.

[Mike Keers]

Well, just want to thank you guys for the responses. I also talked with a coupla friends with some experience, and I'm forming the conclusion that the tanks themselves are probably more or less reliable (seen a few plastic ones fail in my time too), and the key, as mentioned a few times above, is in the installation, to reduce movement and chafe. Also, a guy who's used them successfully for years says not overfilling them all the time seems to help.

So, good mounting, preventing chafe, proper filling, and it seems they can be as reliable as a plastic drop-in tank, altho perhaps with a limted (ten-year?) life. One advantage would be the ease of replacement if and when they do fail.

The jury is still out on this one. Another option I have is to use rigid plastic tanks and simply use two smaller ones located in other locations.

Now, over the years I have made a few tanks out of ply and poxy, including a fresh water tank of about 28 gallons, and a 25 gallon holding tank. I've never experienced any problems of leakage (and I plan to build in two 45 gallon diesel tanks on this boat). But I did notice an off-odor or taste to the water in my last boat after sitting in the tank for about six months down in tropical Mexico. It was more a mild chemical-type taste than bacterial, but who knows? Simply draining the tank and replacing the water cured that, but I've always wondered if I was drinking trace amounts of Bad Things. I used a 3:1 tank coating type googe for the lining. I've heard there are actually FDA approved epoxies for drinking water, but have no direct knowledge. If I could reconcile this concern, I'd simply make ply and 'poxy tanks. Comments?

Thanks again to all for the thoughful advice and observations all around.

[Mike Keers]

Well, just want to thank you guys for the responses. I also talked with a coupla friends with some experience, and I'm forming the conclusion that the tanks themselves are probably more or less reliable (seen a few plastic ones fail in my time too), and the key, as mentioned a few times above, is in the installation, to reduce movement and chafe. Also, a guy who's used them successfully for years says not overfilling them all the time seems to help.

So, good mounting, preventing chafe, proper filling, and it seems they can be as reliable as a plastic drop-in tank, altho perhaps with a limted (ten-year?) life. One advantage would be the ease of replacement if and when they do fail.

The jury is still out on this one. Another option I have is to use rigid plastic tanks and simply use two smaller ones located in other locations.

Now, over the years I have made a few tanks out of ply and poxy, including a fresh water tank of about 28 gallons, and a 25 gallon holding tank. I've never experienced any problems of leakage (and I plan to build in two 45 gallon diesel tanks on this boat). But I did notice an off-odor or taste to the water in my last boat after sitting in the tank for about six months down in tropical Mexico. It was more a mild chemical-type taste than bacterial, but who knows? Simply draining the tank and replacing the water cured that, but I've always wondered if I was drinking trace amounts of Bad Things. I used a 3:1 tank coating type googe for the lining. I've heard there are actually FDA approved epoxies for drinking water, but have no direct knowledge. If I could reconcile this concern, I'd simply make ply and 'poxy tanks. Comments?

Thanks again to all for the thoughful advice and observations all around.

[paladin]

If you build the tank from plywood and epoxy...let the epoxy cure for a couple of weeks then steam out the inside of the tank with hot steam/boiling water...then after drying it out coat the insides with hot melted wax as used for canning foods. My Thunderbird had built in water tanks...no epoxy...but after construction the tanks had poured in very hot melted wax and the outside of the ply was heated overnight with some large heat lamps and then the excess wax poured out.....water was sweet tasting and never leaked in 6 years... tongue.gif

[paladin]

If you build the tank from plywood and epoxy...let the epoxy cure for a couple of weeks then steam out the inside of the tank with hot steam/boiling water...then after drying it out coat the insides with hot melted wax as used for canning foods. My Thunderbird had built in water tanks...no epoxy...but after construction the tanks had poured in very hot melted wax and the outside of the ply was heated overnight with some large heat lamps and then the excess wax poured out.....water was sweet tasting and never leaked in 6 years... tongue.gif

[paladin]

If you build the tank from plywood and epoxy...let the epoxy cure for a couple of weeks then steam out the inside of the tank with hot steam/boiling water...then after drying it out coat the insides with hot melted wax as used for canning foods. My Thunderbird had built in water tanks...no epoxy...but after construction the tanks had poured in very hot melted wax and the outside of the ply was heated overnight with some large heat lamps and then the excess wax poured out.....water was sweet tasting and never leaked in 6 years... tongue.gif