Stone dumping For DeepRock (owned by a Joint-Venture of Boskalis and Tideway) HI delivered a gripper system in 2002. The Seahorse was already equipped with a complete 'Stone dumping' system. Stone dumping is used for the protection of pipelines on the seabed. On the back of the ship a crane is mounted for the creation of so-called 'Glory-holes'. In these holes in the seabed (30 x 80m) the stop-valves of oil wells are safely protected against ice packs. The job had to be done over Northern Canada. Huisman-Itrec also delivered the winching-system, the crane and the energy supply.