A pair of dual fuel (diesel and LNG) RAstar 4200-DF standby vessels have recently entered service with Hongkong Salvage & Towage (HKST). Built by Cheoy Lee Shipyards, LNG Sentinel I and LNG Sentinel II were specifically designed for service at the Hong Kong LNG Terminal Limited (HKLTL) import terminal.
Featuring a unique electrical propulsion system with Z-drives that can receive power from both diesel and dual fuel (diesel and LNG) propulsion gensets, these vessels will help maintain a safety zone around the terminal and assist with berthing of LNG carriers to the jetty. They will also transport personnel plus equipment between Hong Kong and the floating regasification and storage unit (FSRU) and jetty. Their standby duties may include emergency towing of the FSRU, fire-fighting, spill response, and rescue.
Three classification societies
Working closely with both HKST and Cheoy Lee Shipyards through the design process was key to enabling Robert Allan Ltd. (RAL) to design this vessel pair that are customized for the missions for which they will be tasked.
These vessels are notably the 8th and 9th LNG dual fuel tugs completed to five different Robert Allan Ltd. designs, with three classification societies, and for service on three continents, which is illustrative of the company’s unique expertise in the design of workboats incorporating the use of alternative fuels and propulsion technologies for any service, class, or region.
Key particulars
- Length, overall: 42.0 metres
- Beam, moulded: 16.0 metres
- Depth, moulded: 6.6 metres
- Maximum draft (navigational): 6.8 metres
- Gross tonnage: 1275 tons
- Capacities
- Diesel oil: 265 m3
- LNG (gross volume): 110 m3
- Potable water: 66 m3
- Recovered oil: 46 m3
- Foam: 18 m3
- Dispersant: 12 m3
- Complement: 11 crew + 2 supernumeraries
- Survivors: 20 persons
Major machinery
- 2x Wartsila 8L20DF dual fuel (diesel and LNG) electric propulsion gensets, 1500 ekW each
- 2x Wartsila 9L20 diesel electric propulsion gensets, 1880 ekW each
- 1x Caterpillar C4.4 diesel harbour/emergency genset, 82 ekW
- 2x Wartsila WST-32 fixed pitch Z-drives, 3.3 m diameter, each driven by 3000kW ABB electric motors
- 1x Schottel STT 60 electrically driven fixed pitch bow thruster, 125 kW
- 1x Wartsila LNGPac double wall vacuum insulated IMO Type C tank, with integral tank connection space (TCS) and double airlock
- 1x Palfinger PK65002(M) folding knuckle boom deck crane, 2.8 tonnes at 15.9 metre outreach, and compatible with Dacon Rescue Scoop (RSA 500) personnel overboard recovery system
- 1x Palfinger rescue boat (RSQ 450) under pivoting davit, SOLAS compliant
- MacGregor hydraulic deck machinery package featuring:
- 1x double drum hawser winch with 300 metres of 76 mm synthetic towline per drum
- 1x single drum towing winch and spooling gear, with 1000 metres of 64mm steel wire
- 1x towing pin unit aft, 110 tonne safe working load
- 2x tugger winches, each with 100 metres of 22 mm wire, plus horizontal warping head
- 2x vertical anchor windlasses with 400 mm throat warping heads
- 1x powered boom reel, 200 metres capacity of offshore spill recovery boom
- FFS off-ship fire-fighting system with 2x pumps feeding 2x monitors (each 1,200 m3/hr) plus waterspray
Performance
- Bollard pull: approx. 105 tonnes astern
- Speed: 14+ knots