‘Signet Sirius’, the first of two ART 92-32W Rotortugs designed by Robert Allan Ltd (RAL) was recently delivered by Signet Maritime’s Pascagoula yard.
This is the first ART Rotortug that Signet has built and operated. Designed in collaboration with RotorTug of the Netherlands, the Advanced Rotortugs (ART) incorporate the patented triple Z-drive Rotortug propulsion layout, featuring omni-directional manoeuvrability, 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 two tugs, Signet Sirius and Signet Capella are 31.5m long, and are designed to achieve 92t bollard pull from two engines of 2575 bhp each. The tugs are classed by American Bureau of Shipping, with notations ✠ A1, ✠ AMS, ✠ ABCU, FFV-1, CS-1, ENVIRO, LEV, Escort, USCG Inspected (Subchapter M).
The ART 92-32W is the most powerful 32m ART to date. It is designed to escort deep-draught 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 VLCCs. Collaboration between Signet, RAL and Markey Machinery resulted in a design that exceeded initial design criteria. RAL and Signet’s selected vendors, included Markey Machinery, MTU, Kongsberg, R.A. Mitchell, Buoyant works, Fabtek/Procurve, ABS and others worked together on the vessel’s three CP thrusters and high-torque winches to provide close-quarters ship-handling and constant line time under tension to safely handle laden 300,000-plus dwt ships.
The ART 92-32W is believed to be the first commercial vessel in US 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, which improved the production methodology of the Signet shipyard. All future vessels constructed at Signet will follow the same design regimen. The 3D design process has been shown to reduce 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, other first claimed for SIGNET SIRIUS include:
- First 32m ART to achieve greater than 90t bollard pull
- First towing vessel to receive ABS ENVIRO Notation
- First vessel in the US to achieve ABS Low Emissions Vessel (LEV) Notation
- First vessel in the US to receive ABS CyberSecurity-1 (CS-1) Notation
Image: ‘Signet Sirius’ at work (credit: RAL)
