SCHOTTEL, Spay, Germany, is equipping the world's first large purpose-built 144.3' dual-fuel methanol escort tugs based on the Robert Allan Ltd. RASalvor 4400-DFM design for towage company KOTUG Canada, Dartmouth, Nova Scotia, with rudderpropellers featuring the mechanical hybrid solution SYDRIVE-M.
The tugs — to be named SD Aisemaht and SD Qwiy Aanitsa Sarah — are currently in the final stages of construction at Turkish Sanmar Shipyards, Istanbul, Turkey. After their completion later this year, the new tugs will service Canada’s Trans Mountain Expansion Project, escorting laden crude oil tankers from the outer harbour limits of the Port of Vancouver to the open Pacific Ocean through the commercial shipping lanes of the Salish Sea.
“We are pleased to move forward and implement these newbuild green solutions to the Trans Mountain Expansion Project enhanced tug escort program,” Laurens Korporaal, business development manager, KOTUG Canada, said in a statement announcing the propulsion system. “These tugs, propelled by modern climate-friendly SCHOTTEL propulsion systems, exhibit the aspirations of the British Columbia tug market to improve environmental performance of shipping activity and advance new solutions to local and global environmental challenges.”
In order to provide the best performance for their tasks, the tugs require a propulsion system that offers both transit efficiency and high bollard pull. For this purpose, the vessels are each equipped with two SCHOTTEL SRP 710 RudderPropellers.
The 360° steerable SRP combines bollard pull with high propulsion efficiency and is designed to provide the ships with increased maneuvering capabilities. In addition, the tugs are also each fitted with a SCHOTTEL TransverseThruster type STT 170. With this propulsion system, the vessels are designed to achieve a free sailing speed of up to 14 knots and an impressive bollard pull of over 120 tonnes, making them the most powerful escort tugs in Canada.
Since the tugs will operate along the shores of the Salish Sea and the respective Salish Sea communities including the Sc'ianew First Nation, they have to meet special environmental requirements in terms of their equipment, which is also reflected in the chosen propulsion system. To further optimize fuel savings and reduce underwater radiated noise, all four of the ordered SRP azimuth thrusters feature SCHOTTEL SYDRIVE-M. The mechanical hybrid solution allows the two thrusters per vessel to be driven together by only one of the main engines. This reduces main engine operating hours, resulting in lower maintenance costs as well as less fuel consumption and lower emissions. Furthermore, the system needs no additional electrical components, and the hulls of both tugs are coated with a graphene paint to minimize biofouling and enhance the hull-smoothness of the vessels which reduces underwater radiant noise and makes the vessels more fuel efficient.
The Trans Mountain Expansion Project (“TMEP”) is a recently completed expansion of a 1,180-kilometre pipeline, carrying crude and refined products from Edmonton, Alberta, to the coast of British Columbia, Canada, at Westridge Terminals in Burnaby. The expanded pipeline system has an increased capacity of 890,000 bbls. per day, boosting the number of exports of crude oil by ship significantly.
