Fitting a Water Bladder

[Avayak]

G'day.
I custom built a box to house a Plastimo 200 Lt. water bladder according to the dimensions on the product box 700 x 1750 x 250.
On first fill I realised that the filled bladder transforms from it’s lay flay dimensions into a hotdog shape around 500 x 1600 x 275.
Thus my filled bladder has about 100 mm of slop space all around.
Turning on the calculator I realised that 700 x 1750 x 250 gives a 306 Lt box.
I cannot see the need for this wasted volume and slop space.
Is there a need for it, or is it a problem?
I am contemplating reducing the space to snuggly accommodate the bladder's filled dimensions rather than it’s lay flat size.
I would appreciate comment from anyone who has experience of fitting this type of bladder into a space that is not the lay flat size.
Cheers.

[Shorty]

Because of that very occurrence, I have a 35 gal Vetus where the boat mfg put a 25 gal. Works just fine. In my view, the snugger the better. Don't want it slopping around & abrading.

[Avayak]

Originally Posted by Shorty

Because of that very occurrence, I have a 35 gal Vetus where the boat mfg put a 25 gal. Works just fine. In my view, the snugger the better. Don't want it slopping around & abrading.

Thanks Shorty, the importer was of the same view. No reply from Plastimo. My solution was to make what I've called a snake tank out of PVC pipe. As name implies it snakes around the top of the space drops down works around the bottom out of the box and doubles back down the side to finish with a tape and tail. While the fit was snug I still gave it a few daubs of silicon to eliminate any movement against the box or itself. This gave me a 63 Lt tank, the bladder tabs are pulled back neatly between the layers and it perfectly supports the full bladder with a nice smooth surface.
I've gone from miffed to a happy chappy.

[Wotname]

Nice solution!

[barnakiel]

If you are in a sailing boat that goes out / offshore a lot then the bladder will wallow and in the end chafe. Try to limit its freedom in such cases and it will last longer.

b.

[Randyonr3]

Originally Posted by barnakiel

If you are in a sailing boat that goes out / offshore a lot then the bladder will wallow and in the end chafe. Try to limit its freedom in such cases and it will last longer.

b.

we have two in our 42.. under the settees and dont have any problems..
at one time I was concerned and attached the tabs but found the lines would change length wether it was full or empty.. I'm on my second set and they work fine to just leave them alone.. they kinda sorta find there own space..
never had an issue offshore, but we also seem to have a stable ride..
One thing I have done and it might interest you..
Because ours are on the right and left side of the boat, I've installed two small pumps to transfer the water to the side I wish.(back and forth). something like movable balest......
as I said, I'm on my second set.. the tanks will take on the taste of the water you put into them, due to them being plastic.. we were using water from one sorce that had a lot of ground minerals in it and never could get the taste out of the tanks from then on.. (sulfur in the ground water)...
smelled like rotton eggs when you turned the tap on..
We now filter all water going into the boat........

[barnakiel]

Ours was the triangular type apparently sitting pretty snug in the V of the bow. Apparently. We had it.

Went for plastic rigid placed midships. Will report one day if they are any better.

b.

[Randyonr3]

b.
did you make your own tank?
been thinking of replacing ours with a poly and welding them together from pieces to fit the contour of the inside of the hull..
seems I could fill the space that has been in question at the sides and gain more volumn..
Cant find any positive info on what is needed.. looks like a new thread..

[barnakiel]

I think this is the best way to go but I cannot weld poly. How is it done? Got a link perhaps?

I got the biggest one that fits in the space and sure the space being angled at the bottom some volume is lost and support is less than perfect.

Welded plastic tanks could be very nice but I asked around and nobody seems to make them locally.

b.

[Pete7]

Oops, new fred has appeared:

http://www.cruisersforum.com/forums/...tml#post939942

Pete

[barnakiel]

THX, appreciated. Would be nice to make my own that would fit the shapes of the boat. More water = more cruising range.

b.

[Avayak]

Just revisiting this post. Two years on and bladder began to leak. As I have been doing a lot of restoration work the boat has had virtually zero rough water use and the bladder while full had not been plumbed in.
Thus no abrasion from rough water or from being filled and emptied.
My assumption, rightly or wrongly is that like a water bed I once had algae in the water had grown into and through the plastic bladder. Water beds have to have a sterilant to protect against this.
Be this the cause or not, the bladder chucked and a poly tank was installed. Need something more fail safe.


Sent from my iPhone using Cruisers Sailing Forum

[GuidoY]

I was looking at this with not a little interest. Now I can take it off the list as quickly as I put it on. One less thing!

[Scot McPherson]

Originally Posted by Avayak

Just revisiting this post. Two years on and bladder began to leak. As I have been doing a lot of restoration work the boat has had virtually zero rough water use and the bladder while full had not been plumbed in.
Thus no abrasion from rough water or from being filled and emptied.
My assumption, rightly or wrongly is that like a water bed I once had algae in the water had grown into and through the plastic bladder. Water beds have to have a sterilant to protect against this.
Be this the cause or not, the bladder chucked and a poly tank was installed. Need something more fail safe.


Sent from my iPhone using Cruisers Sailing Forum

Thanks for posting this. In another thread about repurposing a holding tank, this was one of the solutions proposed. I thought that the motion would put holes in the bag eventually and your reply is very timely.

I would think lining your tank with zein would be a good way to seal the contents from the tank's materials.

[DeepFrz]

Thanks for reporting your experience.