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First-in-class Robert Allan LNG terminal escort tug delivered

May 28, 2019 08:48 AM

Courtesy Robert Allan Ltd.

(VANCOUVER, British Columbia) — Vittoriosa, the first RAstar 3000-W-class liquefied natural gas (LNG) terminal escort tug, was delivered in late April to Tug Malta, a wholly owned subsidiary of the Rimorchiatori Riuniti Group, Genova Italy.

The vessel was constructed by Turkish builder Med Marine Shipyards at their Eregli Shipyard on the Black Sea. Med Marine, a longtime builder of Robert Allan Ltd. designs, recently began expanding its portfolio of tugs and the RAstar 3000-W is the latest addition to their product line to be delivered. Vittoriosa will soon commence operations for Tug Malta at Malta’s Delimara LNG terminal.

The RAstar series tugs are well proven LNG terminal escort/support tugs in operation at major LNG facilities worldwide. They are a unique class of high-performance ASD tugs, designed with a sponsoned hull form proven to provide significantly enhanced escort towing and seakeeping performance. Roll motions and accelerations are less than half those of comparable sized “standard” tug hulls. These tugs are high-powered and are ideally suited for escort operations in weather and exposed areas such as encountered at many new LNG terminals where a high standard of seakeeping is required.

Beyond the high-performance hull form, the RAstar 3000-W design for Tug Malta has numerous other features for LNG terminal support. The bow fendering system is designed for a low contact pressure requirement of 20 T/m². A gas detection system is fitted to warn the crew of a potential hazardous atmosphere. Ventilation dampers can be remotely closed. All essential electrical equipment on deck is certified safe and type suitable for use in a Zone 2 LNG environment and all non-essential electrical equipment can be electrically isolated. Fi-Fi 1 capability with water spray is provided along with a large capacity of firefighting foam.

The RAstar 3000-W is designed with a low profile for operation under the flare of assisted ships. The wheelhouse provides 360-degree visibility from the operator’s position and superb sight lines to the fore and aft working decks. The fore and after decks can be fitted with various deck machinery options. Tug Malta elected to use a double-drum winch with dual aperture escort staple on the fore deck and a towing hook on the aft deck with the option for future installation of an aft towing winch.

Vittoriosa was designed and constructed to RINA rules with the following notations: RINA C ✠ HULL ✠ MACH; ESCORT TUG; FIREFIGHTING SHIP 1; WATER SPRAYING; UNRESTRICTED NAVIGATION; AUT-UMS; AUT-PORT; COMF- NOISE C; COMF-VIB C; INWATERSURVEY

Particulars of the RAstar 3000-W tugs are:

Length overall: 29.70 m
Beam, molded, extreme: 13.30 m
Depth, molded (hull): 5.45 m
Operating draft (100 dwt): 5.42 m
Load Line draft (250 dwt): 5.95 m
Gross tonnage: 481

Tank capacities are:

Fuel oil: 203 m3
Potable water: 18 m3
Foam: 10 m3
Sewage tank: 5 m3
Graywater: 5 m3

The vessel’s accommodations are outfitted to MLC-compliant standards for a crew of up to eight personnel. The master and chief engineer cabins with private ensuite washrooms are located on the main deck with three double crew cabins’ all with private ensuite washrooms, are located in the lower accommodations.

Main propulsion for the tug comprises a pair of box cooled MTU 16V4000M65L diesel engines, each rated at 2,560 kW at 1,800 rpm, driving through a carbon-fiber floating shaft system a Rolls-Royce, US 255 P30 FP fixed-pitch z-drive unit with HD slipping clutches on the drive units.

The double-drum escort rated bow winch, Rolls-Royce model ETWH 2500/1000 is driven by two high pressure hydraulic PTO pump units off the front of the main engines. First layer pull on low speed is 102 tonnes at 9 m/min and high speed pull is 12 tonnes at 57 m/min. Rendering is 145 tonnes at 14 m/min. low speed and 24 tonnes at 51 m/min high speed.

Two identical diesel gensets each with a power output of 99 ekW provide electrical power to the vessel.

Ship-handling fenders at the bow consists of an 800 by 500 cylindrical fender with 600 by 300 mm “M” block fendering below. A 300 by 300 hollow “D” fender provides protection at the main deck sheer line and along the knuckle, and 600 by 300 mm “M” block fendering is used at the stern.

On trials,Vittoriosa demonstrated nearly equal ahead and astern performance:

Bollard pull: 81.5 tonnes ahead, 81 tonnes astern
Free running speed: 13.8 knots ahead, 13.7 knots astern

For more information on the RAstar 3000-W or any other vessel designs developed by Robert Allan Ltd., contact design@ral.ca.

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