Underwater Cutting Methods Tested in NHC’s Dive Tank

The NHC Dive Tank and outdoor facilities were used by a client for in-depth trials investigating the effectiveness of underwater cutting methods on large subsea pipeline flanges.

Trials were needed to identify the safest, most effective and cleanest method of cutting through solid metal bolts used on various subsea pipe flange installations and avoiding damage to the sealing flange faces. Equipment which operates for many years on the seabed is exposed to harsh corrosive elements.

Bolts are particularly susceptible to corrosion and fusion, producing limitations on methods of removal and repair after many years in service. Various removal and cutting methods were thoroughly trialled including hydraulic splitting tools, hydraulic torque tools, disc cutters and Broco cutting rigs.

Dry trials were performed in NHC’s outdoor yard where a purpose-built, fully-screened weld/cutting tent provided a safe workspace for the divers to practice before entering the water.

NHC’s large Dive Tank then provided the perfect underwater area for the trials to take place. The Dive Tank is complete with a 3-diver capability air diving control system, which allows live communication, full video-streaming and recording of each trial. NHC is dedicated to providing a flexible testing facility and will work alongside clients to accommodate a wide range of trials and testing operations.

Press Release, September 08, 2014