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Siemens June 2021


A dam good solution

Ship & Boat International eNews: February 2021



The US Army Corps of Engineers is due to take delivery of a compact tug, launched in January by WCT Marine & Construction of Tongue Point, in the State of Washington. The tug will be tasked with handling the bulkhead stoplogs at the 809m-long Little Goose Dam – a run-of-the-river hydroelectric dam located on the Snake River in the State of Washington.


The tug measures 7.92m in length and 4.11m in beam – the restricted breadth permitting the boat to be legally transported on state highways by truck. The tug’s designer, Tullio Celano of Crescere Marine Engineering, had to match “an elevated height of eye for the operator” with a draught of only 1.52m.


The function of the stoplogs is to prevent floating objects from entering the penstocks. While some stoplogs are positioned by crane or manually by personnel, Celano tells Ship & Boat International: "These navlock stoplogs, or bulkheads rather, are more like drydock caissons that are floated into place: they are much too heavy to be lifted." Hence, the requirement for tug assistance. 


Twin Cummins 6.7 QSB engines, rated 224.5kW each, provide the tug’s power, granting it a bollard pull of 5tonnes. Each engine also turns an open, four-bladed, 813mm x 508mm Workhorse propeller via a ZF 325-I gear with 2.957:1 reduction.


The tug has a fuel capacity of 1,325litres, has been classed by ABS and meets US Coast Guard CFR rules for towing stability at full power.