VESSEL REVIEW | Rachael Allen – Low-emission workhorse for Foss’ northern California towing operations

US towage operator Foss Maritime has taken delivery of a new ASD tug from Nichols Brothers Boat Builders (NBBB) of Freeland, Washington.

The ABS-classed Rachael Allen is the fourth all-steel tug in a series ordered by Foss from NBBB for use in tanker escort and general ship assist duties in the waters off northern California, particularly off the ports of Los Angeles and Long Beach. The vessel's design was developed by naval architects Jensen Maritime, which has since become a marine engineering business unit under the Crowley Maritime group.

The tug has an LOA of 103.75 feet (31.6 metres), a beam of 40 feet (12.2 metres), a draught of 19.5 feet (5.9 metres), and a displacement of 843 tons (765 tonnes). Accommodations are available for six crewmembers and two additional personnel. The accommodation spaces, the pilothouse, and the engine room have all been fitted with enhanced acoustic insulation for improved crew comfort even during days of continuous heavy-duty operations.

Power is provided by a pair of MTU 16V4000M65L diesel engines that each produce 6,866 hp (5,120 kW) and are compliant to US EPA Tier IV emissions regulations. There is also a selective catalytic reduction (SCR) system for reducing NOx emissions to near-zero. The main engines drive two Kongsberg Maritime US255 Z-drive mounted, fixed-pitch propellers to deliver an impressive bollard pull of 91 tons (83 tonnes).

The tug's electrical systems draw power from two John Deere 6068AFM85 generator sets that each produce 120 kW and are EPA Tier III-compliant. The towing equipment includes a Markey DEPCF-52R winch at the bow and a Markey TESD-34AS double drum escort winch at the stern, ensuring increased operational flexibility in assisting the ships that sail and out of two of northern California's busiest ports. For added safety, the controls for the winches are found only in the pilothouse, which also has upward-looking windows to provide the crew with improved visibility and enhanced situational awareness when assisting larger vessels.

Rachael Allen has also been selected for the installation of an autonomous command and control system developed by unmanned systems specialist Sea Machines Robotics. The installation will make the Foss newbuild the first US-flagged harbour tug to integrate autonomous systems in real-world commercial operations.

The system's capabilities include transit autonomy, obstacle detection and avoidance, and remote access of the tug's on-board machinery, a feature that will allow personnel to manage and support operations from anywhere on board the vessel or even from shore. Although Rachael Allen was delivered with the autonomous command system and supporting hardware already fully integrated, the capability of the technology will be activated in stepped phases over the course of six to nine months to ensure full visibility and acceptance from all operational stakeholders.

Foss will use its existing fleet monitoring centre personnel to monitor the tug's systems and operating domain via streaming video and sensor data.

See more stories from this month's Tug and Salvage Week here.