A new class of RAstar escort tugs initiated by Sanmar and Robert Allan Ltd.

February 19, 2016

Sanmar A.Ş. delivered the Robert Allan Ltd. designed RAstar 3200W escort tugs Civitavecchia and Saraceno Primo to Italian tugboat operator Italtugs S.p.A. to close out the very busy tug-building year of 2015. The tugs were constructed at Sanmar’s Tuzla facility, the greenest shipyard in Turkey.

The RAstar Offshore/Escort Tugs designation is reserved for a unique class of ASD tugs, designed with a sponsoned hull form, a concept originated by Robert Allan Ltd. 20 years ago, and which has been proven in both model and full-scale testing to provide significantly enhanced escort towing and seakeeping performance. Motions and accelerations are less than half those of comparable sized “standard” tug hulls. It is interesting to note that others are now attempting to emulate this concept. Civitavecchia and Saraceno Primo are the first of the latest evolution of the remarkably successful RAstar tug series, now entering its 20th year of ongoing progressive development.

Robert Allan Ltd. worked very closely with Sanmar A.Ş. to develop this new class of 80-90 tonne BP tugs, targeted at the European market. The new RAstar 3200W class design was tailored to provide ultimate operational flexibility and a level of safety and redundancy not achievable with a smaller vessel. Specific features include a very low profile, wide beam, and shortened forecastle deck while maintaining the sea keeping and escorting capabilities of the RAstar class. With space and volume at a premium, accommodation, locker, and deck arrangements were optimized for utility. Unique additions include a bow thruster and deck crane to aid in oil recovery operations. With an emphasis on technology and quality, this class of tug was fitted with top of the line equipment and constructed with crew comfort as a priority. True workhorses, these vessels have been designed to carry 210 m³ fuel oil and 63 m³ potable water for extended endurance, estimated upwards of 2700 nm cruising at 11 knots.

The principal particulars of the RAstar 3200W class tugs are as follows:

The tugs have been built and classed by RINA with the notation:

RINA C ✠ HULL, ✠ MACH, ESCORT TUG, FIRE FIGHTING SHIP 1, WATER-SPRAYING, SALVAGE TUG, OIL RECOVERY SHIP-FLASH POINT > 60°C, UNRESTRICTED NAVIGATION, AUT-UMS, INWATERSURVEY

The vessels also meets all applicable MLC 2006 requirements.

The propulsion machinery consists of a pair of MAN 7L27/38 main engines each producing 2,555 kW at 800 rpm This power is transmitted via Rolls Royce US25 CP Z-Drive thrusters with 2.8 m diameter propellers.

The Civitavecchia and Saraceno Primo, as illustrated in the accompanying general arrangement drawing, have the following features:

Arrangement:

• Wheelhouse; arranged to provide maximum all-round visibility, with overhead viewing windows, a split console forward, from where all steering and fire-fighting controls are conducted
• A chart table and communication station located to Port
• Well-appointed individual cabins for the Master and Ship’s Officer, with private lavatory facilities
• Two additional single crew cabins and two double berth cabins for a total of 8 persons, each cabin with ensuite lavatory facilities
• A generous Galley and a Mess/Lounge with dining table and benches, lounge chairs, and lounge amenities
• Ample deck locker storage for basic tug servicing equipment and deck gear

Deck Machinery:

• On the aft deck for towing and salvage duties:
  • A high performance towing winch with a 200 tonne brake rating,
  • 90 tonne SWL tow hook, and
  • a heavy duty towing bitt
  • gob eye, rated 100 tonnes SWL installed flush
• On the fore deck:
  •  a double drum, high-performance escort winch with a 200 tonne brake rating
  •  escort staple
  • A quick-release towing hook for towing and ship assist operations off the bow
  • Two vertical anchor windlasses
• A deck crane of 1.1 tonnes capacity at a maximum range of 12.3 m is fitted at bridge deck level, aft of the funnel
• A SOLAS-rated Rescue boat with davit is also fitted on bridge deck.

On trials, Civitavecchia and Saraceno Primo demonstrated excellent maneuverability, directional stability, full controllability in both fore and aft directions, and were vibration-free throughout the full range of operations. All performance expectations were met with the following results:

For more information on the Civitavecchia and Saraceno Primo, RAstar Class tugs in general, or any other designs or consulting services offered by Robert Allan Ltd., please contact design@ral.ca.