Continuing the theme of dry access with minimum disruption to operations, Limpet dams need not only be the solution to fixed structures in tidal environments. Special dams have been used to allow access to continually moving structures floating with the tide, but requiring maintenance while still in duty See image 1.

One such project involved the sliding retention claw mechanism for a large pontoon See image 2. The dam was constructed to give access around the retention clamp and its 1900mm dia pile (to which the sliding seal was made). The dam not only accommodated the 8m vertical tide movement but also a 200mm omni-directional lateral movement caused by 7knot tides .

See also: Humber Sea Terminal Project datasheet.

Another special was built to accommodate the repair of a lock gate leading to the need to seal against 6 different surfaces in a three-dimensional arrangement in a quadrant configuration. The design was complicated further by economy requiring that the dam be handed for use on both sides of the gate See image 3.

See Liverpool Project datasheet for more information.