Signet Shipbuilding delivers first ART 92-32W Rotortug®

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The Signet Sirius. Signet Maritime photo.

The Signet Sirius. Signet Maritime photo.

SIGNET SIRIUS, the first of two ART 92-32W Rotortugs® was recently delivered by Signet Maritime at their Pascagoula Shipbuilding and Repair facility. This is the first ART Rotortug® that Signet has built and operated in their fleet. Designed by Robert Allan Ltd. in collaboration with RotorTug BV, the Advanced Rotortugs® (ART) incorporate the patented triple Z-drive Rotortug® propulsion layout, featuring omni-directional maneuverability, and the benefits of a fully redundant and precise propulsion machinery configuration. The Rotortug® concept offers increased redundancy for ship-handling, terminal support, and escort towing, as well as enhanced crew safety.

Particulars of the SIGNET SIRIUS and SIGNET CAPELLA are as follows:

  • Length overall: 103′-4″
  • Beam, moulded: 45′-6″
  • Depth, moulded: 15′-7″
  • Maximum draft (overall): 21′-6″
  • Power: 3 x 2,575 hp
  • US gross tonnage: 299
  • Bollard pull: 92 metric tons

The tugs are classed by American Bureau of Shipping, with the following notations:

✠ A1, ✠ AMS, ✠ ABCU, FFV-1, CS-1, ENVIRO, LEV, Escort, USCG Inspected (Subchapter M)


The ART 92-32W is the most powerful 32 metre ART to date. It is designed to escort deep-draft VLCCs in and out of the Port of Corpus Christi. Extensive analyses and simulations have been performed to confirm the suitability of the ART 92-32W for the proposed operations, including simulations at the Seamen’s Church Institute and TDT-Sim analysis by RAL, in conjunction with Markey Machinery, to ensure proper winch selection for the tug to meet the environmental criteria for the escort and docking of the VLCC’s. The close collaboration between Signet, Robert Allan Ltd., and Markey Machinery resulted in truly unique, next-generation Advanced Rotortug design that exceeded initial design criteria. Robert Allan Ltd. and Signet also collaborated with Signet’s selected vendors, including Markey Machinery, MTU, Kongsberg, R.A. Mitchell, Buoyant works Ltd., Fabtek/Procurve, ABS and others to ensure the development of the highly capable escort/terminal tug with the combined maneuverability of three controllable-pitch thrusters and the high-speed, high-torque performance of the AGILE winches: unmatched close-quarters ship-handling and constant line “time under tension” to safely maneuver laden 300,000 DWT+ ships.

The ART 92-32W is the first commercial vessel in U.S. history to be produced using 3D structural models in combination with key plans in design, approval, and construction. The full cycle of design and construction has been completed in 3D, and it’s improved the production methodology of the Signet shipyard significantly. All future vessels constructed at Signet Shipbuilding and Repair (SS&R) will follow the same design regimen.

A 3D design process reduces costs and time investment, while streamlining interaction between all stakeholders throughout the design, verification, and construction phases, without compromising safety.

In addition to using 3D structural design methods, the SIGNET SIRIUS has several additional firsts, including:

  • First 32 metre ART to achieve greater than 90 tonnes bollard pull
  • First towing vessel to receive ABS ENVIRO Notation
  • First vessel in the United States to achieve ABS Low Emissions Vessel (LEV) Notation
  • First vessel in the United States to receive ABS CyberSecurity-1 (CS-1) Notation