Signet Maritime delivers the first of two advanced Rotortugs

Signet Sirius [Photo: Signet Maritime]

Signet Maritime’s Pascagoula, Miss., shipyard has recently completed the Signet Sirius. The first of two ART 92-32W Rotortugs, it and is the first ART (advanced Rotortug) that Signet has built for its fleet.

Designed by Robert Allan Ltd. in collaboration with RotorTug BV, the vessels 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.

The vessel has the following dimensions:

• Length overall: 103 feet 4 inches
• Beam, molded: 45 feet 6 inches
• Depth, molded: 15 feet 7 inches
• Maximum draft (overall): 2 feet 6 inches
• Power: 3 x 2,575 hp
• U.S. gross tonnage: 299
• Bollard pull: 92 tonnes

It is ABS classed with the notations ✠ A1, ✠ AMS, ✠ ABCU, FFV-1, CS-1, ENVIRO, LEV, Escort, USCG Inspected (Subchapter M)

Designed to escort deep-draft VLCCs in and out of the Port of Corpus Christi, Texas, Signet Sirius is the most powerful 32-meter ART to date, with a bollard pull of more than 90 tonnes.

Extensive analyses and simulations were performed to confirm the suitability of the ART 92-32W for the proposed Corpus Christi operations. These included simulations at the Seamen’s Church Institute and TDT-Sim analysis by Robert Allan Ltd., in conjunction with Markey Machinery, to ensure proper winch selection for the tug to meet the environmental criteria for the escort and docking of VLCCs.

The close collaboration between Signet, Robert Allan Ltd., and Markey Machinery resulted in a 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 was completed in 3D, improving 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.