Cruising Combi

Research by Vickers Ulstein has indicated that its combi-thrusters could be used in cruise ships. In addition to its bow thruster role, the unit, available in ratings up to 2,000kW (2,680 bhp), can be used as a get-you-home drive or as slow-speed propulsion.

Initial trials using hull lines of a cruise ship showed the system would increase the hydrodynamic resistance by ten per cent compared with the same hull with two tunnel thrusters and a balance tunnel. Following modifications, this was reduced to two per cent.

When lowered, the unit provides equal thrust to port and starboard by swivelling, and can be more effective than a tunnel thruster at higher ship speeds, says the company. While retracted into the hull the unit sits in a recess and acts as a normal thruster without the increased draft incurred when the unit is lowered.