Schottel has been selected by Birdon America to supply components to 27 vessels of the US Coast Guard Waterways Commerce Cutter (WCC) programme with rudder propellers, which will increase efficiency and reduce environmental impact.
US Coast Guard prime contractor Birdon America, designing the cutters and is expected to construct 16 River Buoy Tenders (WLR) and 11 Inland Construction Tenders (WLIC). The cutters will be built at Birdon’s recently acquired Bayou La Batre shipyard in Alabama. Up to four cutters are expected to be delivered annually over the course of the next eight years, gradually replacing ageing vessels.
Each SRP 210 rudder propeller unit features an input power of 597kW (800hp) and a propeller diameter of 1.3m. The thrusters are fitted with Schottel’s SDC40 nozzle, which combines compact design and high propulsion efficiency. Hydrodynamically optimised protective grids on the nozzles will increase the safety of the propellers in case of collisions with debris. Schottel DuroVario-S slipping clutches will allow for smooth start-up and overall improved handling of the thrusters for precise manoeuvring and will reduce the environmental impact during berthing operations. Enabling the WCCs to operate in both deep and shallow waters, the SRPs will allow the vessel to achieve a free-running speed of 11 knots or more.
The propulsion system of the WCCs will be equipped with Schottel’s LeaCon sealing system, certified by DNV, and which offers protection against the contamination of river and seawater by operating materials and vice versa. LeaCon works with an intermediate chamber design and multiple seals on the propeller shaft and steering stem that separate lubricants from water. The system is equipped with a monitoring and alarm unit that continuously checks the condition of the seals. LeaCon is considered a non-oil to water interface, thus the thrusters can be operated without EALs and fulfil current VGP regulations. Further, the scope of supply is completed by Schottel’s condition monitoring system MariHub to enable condition-based maintenance via an onboard display.
WCCs are considered to be essential to maintain and protect the US inland waterways transportation system. About 630m tons of cargo move through these waterways annually. The current inland tender fleet has an average age of more than 57 years and is approaching obsolescence. The new vessels will feature improved habitability and will accommodate mixed-gender crews. The first of the new WCCs is planned to be operational by 2027.
Image: Two WCC variants: Top, Inland Construction Tender; bottom, River Buoy Tender (source: Birdon America)
