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  • Writer's pictureThe Yacht Channel

Captain/Designer Grant Maughan discusses his conversion design concept for a North Sea Stand-By Rescue vessel.

This vessel is sister-ship to one of our conversion projects that is currently underway. The designers claim that the vessel is derived from the UT704 and the UT712 two of the best known hulls in the North Sea, and the proven hull form together with the latest developments in both hardware and software make the Havila Star an impressive craft.

The design is superficially similar to those proffered by IMT and others, who have taken the basic North Sea anchor-handler shape and moved the bridge back into a more central position. This shift aft has many advantages for the ERRV and its crew. By moving the superstructure, aft the vessel can more easily be provided with a raised bow, which offers protection from the weather, particularly for the fast rescue craft which can be set towards the mid part; the best position for launching. A more central position for the accommodation also provides greater comfort for the crew. Wonderful as the hull form of the 704 might have been, the position of the accommodation on the bow gave them the ability to throw sleeping seafarers up in the air and then move the bunk out of the way.

The 719R has a number of unusual features one of the most noteworthy being twin azimuthing thrusters for the main propulsion, shaft driven from the main engines which are conventionally sited forward of amidships in the machinery space. To drive the thrusters the engines are angled front down and the shafts are angled up at about fifteen degrees  to a point just under the main deck at the aft end, where they are mated to the thruster gearboxes.

Azimuthing thruster for main propulsion provide great flexibility and though shipmasters who have commanded ships with such set-ups have said that they take some getting used to after conventional propeller and rudder configurations.

At the forward end the ship is provided with a 515 kW tunnel thruster and a 735 kW azimuthing thruster. Azimuthing thrusters seem to have become extremely popular despite the possible disadvantages of breaking them off in shallow water, probably because they can propel the ship forwards all by themselves. Although neither the builders or the owners claim a speed for the ship being powered by the forward azimuthing thruster alone, it is probably about six knots. The azimuthing thruster is powered by its own diesel and to provide electric power a shaft generator is fitted to one of the main engines.

The ship is claimed to be capable of towing a 100,000 tone tanker  for which role it is provided with a compact Brattvag towing winch. One assumes that the designers took the manoeuvrability of the ship into account when designing the towing configuration. The gob eye and the towing stops on the crash barrier are set well aft indicating that they no longer consider it necessary for the tow wire to be able to ride half way up the side of the ship when a turn is required. Of course, properly operated, the Havila Star can be made to move sideways on the end of the tow wire so that the ship described an arc from, in this case, the bow of the ship. A bollard pull of 60 tonnes is suggested using both main engines and the azimuthing bow thruster.

For its role as an ERRV the ship is provided with two 11.5 daughter craft and two lesser FRCs all of them mounted on heave compensated davits. This ship is to work for Shell as is its sister the Havila Tigris, and that operator's development of the daughter craft principle was thought to be radical before the arrival of "Jigsaw".(Those confused by reference to puzzles and the demise of the ERRV need to see the stuff about BP's Jigsaw). 

Hence it is probable that the daughter craft will be well used. The ship is also provided with two Dacon scoops effectively deployed from a position just aft of the accommodation. Although forward vision, at the downward angle which might be required to recover people from the water using the scoop is limited, there are positions at the bridge wings for using the joystick.

It is possible for the ship to operate in its ERRV role even if the deck is full of cargo since a second winch down area is provided on the forecastle. However they are not, as far as is known, to be used for winching down personnel at crew changes, as is apparently the fate of some stalwarts at other locations in the North Sea

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