German propulsion manufacturer SCHOTTEL has been selected to equip a newly built harbour tugboat for the Saint Lawrence Seaway Development Corporation (SLSDC) with medium-sized azimuth thrusters. The vessel is under construction at the U.S. shipyard Washburn & Doughty in Maine. The HT-60, the smallest in the harbour tug series developed by the Seattle-based naval architecture firm Glosten, is scheduled for delivery in 2021.

Craig Middlebrook, Deputy Administrator of the SLSDC: “This new vessel will be used to carry out a variety of construction and maintenance duties for the U.S. portion of the St. Lawrence Seaway. These duties include routine maintenance of lock gates, maintenance and positioning of aids to navigation, ice management and removal of accumulated ice from lock walls.”

Fitted with SCHOTTEL LEACON

Two SCHOTTEL Rudderpropellers type SRP 210 FP (500 kW each) with propellers measuring 1.4 metres in diameter are powered by a pair of EPA Tier 3 diesel engines. As a result, the ASD tug will achieve a free running speed of approximately 14.5 knots. The thrusters will be equipped with SCHOTTEL’s patented and DNV-GL type-approved LEACON system, which ensures permanent monitoring of the propeller shaft and steering seals. Considered as a non-oil-to-water interface, this system complies with VGP regulations of the Environmental Protection Agency (EPA) without the need to use environmentally acceptable lubricants (EALs).

At 18.30 metres in overall length, the tug is the right size for manoeuvring inside lock chambers. At the same time, it has an 8.50-metre-wide beam for improved performance in ice and enhanced stability for deck crane operations.

New: medium-sized azimuth thrusters from SCHOTTEL

With medium-sized rudderpropellers, SCHOTTEL is meeting new challenges in the international maritime market. These include shifted engine power classes, new ice class rules and the growing trend towards electric or hybrid-driven vessels. Combining the latest technologies in mechanical engineering, hydrodynamics, and digitalization, the medium-sized thrusters are available in three sizes which correspond to common engine power classes: SRP 210 (560 kW), SRP 240 (750 kW) and SRP 270 (900 kW).