May 11, 2009
Turkish yard delivers Robert Allan LNG terminal tug
The Lamnalco Sana'a, the first in a series of four new high-performance terminal/escort tugs, was recently delivered by Med Marine of Turkey to Lamnalco of the United Arab Emirates.
The Lamnalco Sana'a is the latest in a series of RAstar tugs being built for LNG terminal operations worldwide to new designs developed by Robert Allan Ltd., naval architects of Vancouver, B.C.
The principal particulars of this RAstar 3600 Class tug are:
Length, OA-- 35.80 m
Beam, molded--14.50 m
Depth, Molded-- 6.03 m (above design baseline)
Maximum operating draft -- 6.50 m (to underside of drives)
This powerful escort tug is equipped for typical ship-handling and escort work, with a PLIMSOL model PC-HAETW/CDDG-26-50/250 double drum hawser winch on the fore deck, with a capacity for each drum of 300 m 64 mm diameter plus 150 metres of 80 mm UHMWPE synthetic hawser. The escort-rated winch is driven by a twin-pump electro-hydraulic set, and features a two speed drive system, capable of line recover/rendering at 50 t line pull at 20 m/minute, or 16 t at 60 m/minute (first layer).
The aft deck is fitted with a heavy duty towing winch, a PLIMSOL model PC-HTW/SD-80/150, fitted with 750 m of 52 mm diameter SWR, with a brake capacity of 150 t. The aft deck is also fitted with PLIMSOL pneumatic towing hook with rated load of 100 t and a large knuckle boom crane.
Accommodations are to a very high standard for a crew of up to ten persons. Two spacious officer's cabins on the main deck each have private en-suite facilities, while two of the four double cabins below deck also have private en-suite facilities.
The fully equipped galley serves a large common lounge/mess area, equipped with the latest in video and audio entertainment systems.
Attention was paid throughout the design process to mitigating the propagation of noise and vibration through the essential resilient mounting of the main engines, isolation of all exhaust system components, and the extensive use of visco-elastic floating floor systems throughout.
The wheelhouse is designed to provide maximum all-round visibility from a single split type master console.
The Lamnalco Sana'a is built in accordance with Bureau Veritas regulations for a 1+ Hull, + Mach X Escort Tug, Fire Fighting Ship 1 with water spray, AUT UMS, unrestricted service.
The fire-fighting capability is provided by a pair of FFS main-engine driven pumps, each rated 1,378 cu m per hour, which serve a pair of FFS-1200SB water/foam monitors, each rated at 1,200 cu. m/hour, and the self-protection waterspray system.
Electric power is developed by three 315 kW diesel gensets, and by a third harbor/emergency gen-set, rated at 90 kW.
The main propulsion components include a Wartsila 9L26 rated at 3,060 kW at 1,000 rpm at 100% MCR and LIPS Model CS300-S1WN-K Z-Drives with an input power of 3,060 kW at 1,000 rpm.
The new tug successfully completed trials in Turkish waters, delivering performance beyond all expectations during trials, with the following critical results:
Bollard Pull, ahead: 118 t maximum
Bollard Pull, astern: 110 t maximum
Free running speed, ahead = 15.1 knots
The RAstar design hull form incorporates a significant sponson on the upper hull sides. When the tug is heeled over under influence of the towline during an escort operation, the "downhill" sponson is submerged and a large righting force is generated to improve the stability, thus increasing the towline force. In addition, the hull has a large foil-shaped skeg, also designed to increase indirect towline forces. The RAstar hull form also provides dramatic reductions in roll amplitude and roll accelerations, thus providing a safer and more comfortable platform for crews, who are now being asked to conduct docking operations at LNG terminals and similar installations in up to sea-states of 3.0 m significant wave heights.