Water Tank for hull set-up

Hi everybody,
does any one made already a simple dismountable water tank for hull measurements ?
On MY n°133 I have seen a couple of pictures showing this kind of tank but no explanation given on how to make one of about L 5.5 x W 2 x H 2.5 ft.
Large acquariums are very expensive, fragile and non dismountable.
Thanks for any good and simple sugestion

I have seen what are essentially collapsible cardboard boxes made of of corrugated plastic with plastic sheets joints between the sides - used as picnic boxes in the car boot, et. From what I can remember, the design is watertight. If you can find the design they should be copiable even if they are not available in such a large size

One approach is to separate the sealing function from the structural function. Make the supporting box from wood - which might be bolted together. A sheet of heavy plastic film is then draped inside the frame to hold the water. If the gaps the film has to bridge aren’t large, the tank should then work well, with no leaks. After use, the water can be drained, the film folded up, and the “crate” unbolted so that all the pieces lie flat.

Mike Biggs

Thanks Mike,
I was intending to use multilayers wood panels of 1/2 inch, reinforced at the corners , bolted and keept together with belts and then filled with plastic film as used for garden basins.
Do you believe will be strong enough ?