They are flexible, light and form-fitting, and can therefore be installed where it would not be possible to install a rigid water tank, due to the shape of the boat or difficult access. The double envelope principle makes maintenance easy, as the inner chamber can be easily removed from the outer envelope for routine cleaning and examination. The separate chambers allow the water tanks to be flexible enough to adapt their shape during heavy pitching, and to remain rigid enough not to burst under pressure. The water chamber is slightly oversized, thus allowing the pressure to be exerted not directly on the seams, but on the sides of the bladder itself.
All seams are high-frequency welded for top resistance and watertightness.
The outer PVC coated nylon features double seams on all sides, and protects the water chamber from tearing and abrasion.