Steerprop propulsion to power Arctic Security Cutters

Each vessel equipped with two Steerprop SP 120 CRP ARC LM azimuth propulsion units. (Photo: Steerprop)

Finnish marine propulsion specialist Steerprop has secured an order to supply complete propulsion packages for four Arctic Security Cutters (ASCs) being built for the U.S. Coast Guard by Bollinger Shipyards. It is scheduled to deliver the propulsion packages between 2027 and 2029.

The new vessels will operate across all U.S. coastlines, with a particular focus on Arctic missions. They will be constructed to an existing Multi-Purpose Icebreaker (MPI) design, which each vessel equipped with two Steerprop SP 120 CRP ARC LM Contra-Rotating Propellers (CRP) main azimuth propulsion units and two SP 25 TT ARC tunnel thrusters.

During the selection process, Steerprop said it demonstrated that its dual-end propeller CRP concept delivered higher thrust and improved efficiency compared to conventional single-propeller solutions in an MPI reference case.

In model testing conducted in 2024, the CRP system achieved approximately 10% higher thrust using the same power, or the same thrust with 13.9% lower power, compared with a single-propeller system of the same power. Net thrust performance was measured at 10% to 17% higher.

Steerprop’s experience in Arctic operations proved a factor in this latest order award. The company reports it has supplied propulsion systems for one-third of the world’s icebreakers with azimuth propulsion in operation, and offers several proprietary ice-operating design features, including tunnel thrusters that do not require protective ice grids.