The large hydrodynamic and cavitation tunnel of the Hamburg Ship Model Basin HSVA.

A system allowing for the divers under pressure to be safely evacuated from a ship or floating structure to a position where decompression can be carried out.

A chamber or combination of chambers, intended for manned operation at internal pressure above atmospheric.

A self-propelled lifeboat intended for human occupancy in saturated conditions.

A free-floating decompression chamber for human occupancy. It can be maintained with gas mixture under a pressure. In case of emergency, it is launched from a vessel, a rig or a platform in distress and may drift free.

Hyperboloid cooling tower, where the hyperboloid geometry's structural strength is used to support an object high above the ground.

HyperSizer is computer-aided engineering (CAE) software used for stress analysis and sizing optimization of metallic and composite structures. The wind turbine design industry uses the program to design 100-meter long blades that are light and manufacturable.

Hywind Scotland is the world's first commercial wind farm using floating wind turbines, situated 29 kilometres (18 mi) off Peterhead, Scotland.