Rocks & mirror
Encyclopedia of Marine and Energy Technology

Terminal/escort tug LAMNALCO SANA’A


According to the Significant Small Ships of 2009

LAMNALCO SANA’A is the high-performance ASD tug built to the RAstar design developed by Robert Allan Ltd., naval architects of Vancouver, B.C.

The principal particulars of this RAstar 3600 Class tug are: Length, OA: 35.80m, Beam, moulded: 14.50m, Depth, moluded: 6.03m (above design baseline), Maximum operating draft: 6.50m (to underside of drives), Bollard pull, ahead/astern: 118t/110t maximum, Free running speed, ahead: 15.1 knots, Lightship mass: 963t.

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 3.0m significant wave heights.

This powerful escort tug is equipped for typical ship-handling and escort work, with a double drum hawser winch on the fore deck, with a capacity for each drum of 300m of 64mm diameter plus 150m of 80mm 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 50t line pull at 20 m/min, or 16t at 60 m/min (first layer). 

The aft deck is fitted with a heavy duty towing winch, fitted with 750m of 52mm diameter SWR, with a brake capacity of 150t. The aft deck is also fitted with pneumatic towing hook with rated load of 100t 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 have private en-suite facilities each, as well as 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 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 main propulsion components include two Wärtsilä 9L26 engine rated at 3060kW at 1000 rpm at 100% MCR and two Wärtsilä Z-Drives. Electric power is developed by three 315kW diesel gensets, and by a third harbour/emergency gen-set, rated at 90kW. 

The fire-fighting capability is provided by a pair of FFS main-engine driven pumps, each rated 1378 m3/h, which serve a pair of FFS-1200SB water/foam monitors, each rated at 1200 m3/h, and the self-protection waterspray system.

Terminal/escort tug LAMNALCO SANA’A