Two New Tugs to Serve Western Australia

The RT Discovery and RT Endeavour, ART 80-32 class Rotortugs, have been delivered by Cheoy Lee Shipyards to Owner’s Elisabeth Ltd. The vessels are currently in Hong Kong and are ready for deployment to a busy commodity Port in Western Australia. These two vessels represent the first half of Elisabeth Ltd’s four boat order with Cheoy Lee Shipyards. 

The Advanced Rotortug (ART) designs incorporate the patented triple Z-Drive Rotortug, concept, featuring enhanced omni-directional maneuverability and the benefits of a fully redundant and precise propulsion machinery configuration.

The owner as well as Rotortug B.V. provided significant input into the requirements for this design, and Robert Allan Ltd. developed a unique, customized design optimized for their operations.

The ART 80-32 has an installed power of three 1,765kW, delivering well over 80 metric tons of bollard pull in both ahead and astern directions. The hull form has been developed from Robert Allan Ltd.’s escort tugs and has been adapted to suit the Rotortug concept, providing enhanced stability, sea-keeping and escort performance, the designer said. The design process involved a detailed CFD study of different hull forms to determine the preferred hull characteristics. 

Particulars of the new design are as follows:

Hull:

-Length: 31.95 m

-Beam: 12.6 m

-Depth (Least Moulded): 4.82 m

-Extreme Draft 215 DWT: 6.31 m

-Extreme Draft 75 DWT: 5.91 m

-GRT: 491

Capacities:

-Fuel oil capacity: 200 m3 

-Fresh water capacity: 32.8 m3

Machinery:

-Three Main Engines CAT 3512C HD rated 1,765 kW at 1,800 RPM ("C" rated, IMO Tier II Compliant)

-Three Schottel SRP 3000 Z-drives (two forward, one aft) with 2.3 m fixed pitch propellers driven through MCD 3000 LD slipping clutches

-Two CAT C6.6 genset (143 ekW at 1,500 RPM) and one CAT C4.4 genset (51.5 ekW at 1,500 RPM)

-Kraaijeveld Safe Winch Forward electric towing winch and anchor windlass

-Kraaijeveld Safe Winch Aft electric towing winch

-FIFI 1 equipment includes a single 2,850 m³/hr pump driven off the Port main engine, two 1,200 m³/hr monitors, water spray, as well as foam system capability of 300 m³/hr from the starboard monitor.

Ship-handling fenders at the bow comprise an upper row of 800 mm diameter cylindrical fender and a lower course of W-fender. Sheer fenders consist of lightweight Polymarine foam type fender, 300 mm x 300 mm.

The tug was constructed to LR Class requirements with the following notation: LLOYD'S 100A1 TUG, LMC, UMS, IWS, Fire-Fighting Ship 1 (with water spray).

On trials, the RT Discovery and RT Endeavour achieved essentially equal ahead and astern speeds of over 13.5 knots and sidestepped at over 7 knots. 

The vessel has been outfitted to high standards for a crew of six people. The main deckhouse contains the entrance lobby, galley, mess, two officer cabins each with ensuite WCs, and a common WC. The lower deck contains two double berth cabins each with ensuites, a laundry and galley stores. 

The wheelhouse offers exceptional 360 degree views and unobstructed views of the entire fore and aft working decks from a single control station thus improving safety of crew by ensuring working areas around winches, staples and mooring bitts are clearly visible to the operator. 

Entry from the main deck to the engine room is first through the switchboard room which offers sound isolation to the main deck accommodations. Access to the engine room is then through doors leading from the switchboard room.

With the Rotortug thruster configuration, a modern high performance hull form, exceptional 360 degree wheelhouse views, and an optimized and safe arrangement of the tug’s working areas, the RT Discovery and RT Endeavour will be valuable, high performance, workhorses in the demanding service of Western Australian.