The 'Tai Pari' and 'Tai Timu', two RAmparts 2400W Class tugs designed by Robert Allan Ltd, have been delivered by Cheoy Lee Shipyards to the Port of Tauranga.
The 'Tai Pari' arrived in New Zealand on June 5 after a 30-day voyage on her own bottom. The 'Tai Timu' departed Hong Kong on May 30 and is expected to arrive at the end of June. These two vessels represent a significant upgrade to the Port of Tauranga's fleet.
The tugs are 24.40 metres long, 11.25 metres wide, have a depth of 4.22 metres and a draught of 5.40 metres. They are powered by two Caterpillar 3516C HD engines, each rated for 2,350kW at 1,800rpm.
These RAmparts 2400W hulls feature standard RAmparts class characteristics including good dead-rise for improved thruster performance, modest side flare, a half-raised forecastle deck for good sea keeping, and the characteristic conically shaped double chine stern developed by Robert Allan Ltd, and now being oft emulated, ensuring that the tug can run astern at high speed and maintain good control and directional stability. The hull is under the 24-metre rule length for load line and tonnage conventions.
The Port of Tauranga provided significant input into customising the design for their operations. One of the Port's requirements was a high side stepping speed but still capable of some modest indirect towing capability. Robert Allan Ltd thus conducted a detailed CFD study to determine optimal skeg geometry to achieve these requirements. The tests were done self-propelled with the Z-drive thrusters completely modeled including rotating propellers.
Ship-handling fenders at the bow comprise an upper row of 800mm diameter cylindrical fender and a lower course of W-fender. Sheer fendering consists of 300mm D-rubber. "W" block type fendering is fitted at the stern.
Typical of Robert Allan Ltd tug designs, significant noise and vibration reduction measures have been implemented throughout, including resiliently mounted main engines, resiliently mounted gensets and auxiliary engine, high attenuation engine exhaust silencer systems, ventilation intake air silencers, sound dampening deck treatments, and insulation measures.
The vessels have been outfitted to high standards for a crew of six. The main deckhouse contains the entrance lobby, galley, mess, two officer cabins, and a common WC. The lower deck contains two double berth cabins, a common WC with laundry, and a storeroom. The wheelhouse offers excellent unobstructed views of the entire forward and aft working decks and to the contact zones port and starboard.
On trials, both tugs achieved ahead speeds of over 13 knots and side-stepped at over 5.5 knots. Both easily achieved over 70 tonnes bollard pull.