Robert Allan Ltd. Designed ATB Push Tug Island Raider Enters Service

November 22, 2018

Island Tug and Barge Ltd.’s new ATB push tug the Island Raider has entered service pushing the double hulled refined petroleum products barge, ITB Resolution. The vessel was christened September 28th at Island Tug’s facility in Burrard Inlet. The Island Raider is the first of two, twin Z-drive, ATB push tugs for service on the West Coast of North America. Constructed at Island Tug’s Annacis Island Shipyard on the Fraser River, the Island Raider is connected by an articulating pin system to the ITB Resolution which was retrofitted with pin ladders and stern extensions for connecting to the new tug.

Island Tug had a well-defined statement of requirements for the tug and a clear vision of the desired layout and accordingly the design was developed in close collaboration with Island Tug. Partway through construction, Island Tug was acquired by Vancouver Washington based Tidewater Transportation and Terminals, with completion of the vessel falling under the direction of Tidewater’s engineering department.

Robert Allan Ltd.’s engineering team, supported Island Tug / Tidewater throughout the design and construction with a detailed and comprehensive design, engineering, and support package which included:

  • Hull form optimization study using Computational Fluid Dynamics (CFD) resulting in the selection of the low depth to beam ratio, easy to construct hull form
  • Extensive group of design and outfitting drawings
  • Detailed resistance, self-propulsion, propeller design, and pin loading studies, again using CFD
  • Complete production design package including definition of all steel parts and piping spools as well as assistance with jigs for Island Tug’s yard
  • CFD manoeuvring studies (acceleration, crash stop, turning circles, and zig zags) to assist in developing the simulator model for training the operators
  • Engineering support throughout construction of the vessel

Main particulars of the tug are as follows:

  • Length overall: 24.90 m
  • Length Registered: 23.90 m
  • Beam, moulded: 12.50 m
  • Depth, least moulded: 3.65 m
  • Draft: 3.30 m
  • GT (Measured under Transport Canada Regulations): 384

Tank Capacities at 98% are:

  • Fuel oil: 99.8 m³
  • Potable Water: 14.4 m³

Propulsion machinery consists of two Cummins KTA 38 main engines each delivering 634 kW (850 BHP) @ 1800 rpm connected by Centa hollow carbon fibre floating shafts to Rolls Royce US 105 P9 12FP Z-drives with 1.6 m propellers and with integral slipping clutches.

The ATB connection pins are Articouple model FRC 35S designed for 3 m significant wave height. The FRC pin system allows the tug to stay in the notch during all loading/offloading operations by allowing relative vertical movement of the tug and barge while still connected.

The fully air-conditioned and MLC compliant accommodations are laid out to a very high standard for a crew of up to 8 persons with a spacious and bright mess/lounge area, large sized cabins with en-suite facilities, and a well-equipped fitness room. The relatively large wheelhouse has excellent visibility and features a state of the art Alphatron integrated bridge console. Noise levels are very low due to the comprehensive noise and vibration reduction treatments designed into the vessel and the careful application of the treatments by the construction team.

The tug is designed and constructed to Lloyd’s Register Class requirements and for Transport Canada compliance with the following notation:

LR ✠ 100 A1 Tug, MCH, IWS, UMS

With the twin Z-drives on the tug, and the remote operated 360 degree bow thruster on the barge, the combined ATB unit has exceptional manoeuvrability. With a fully loaded barge, a crash stop can be performed in just over 1 combined tug/barge ship length. Additionally, the ATB pushing arrangement brings with it substantially higher efficiency over conventional towing.

The Island Raider / ITB Resolution ATB unit significantly raises the bar for coastal transportation in terms of operating efficiency, fuel efficiency, safety, and crew comfort. For more information on this innovative new ATB push tug, or any other high-performance vessel designs developed by Robert Allan Ltd., please contact

Bright and spacious mess

Stern quarter view: Island Raider’s high quality finish clearly evident