Polar Class engines

Polar Class engines are propulsion and auxiliary engines built to the reinforced power, torque, and reliability requirements of ships notated under the IACS Polar Class rules (PC1 to PC7) for ice operation. Ice loading on the propeller transmits large torque and bending transients into the shafting and engine, so the rules call for ample torque margin, ice-milling load cases on the propeller and shaft, redundancy of essential machinery, and cold-climate provisions for fuel, lube oil, and starting air. The IMO Polar Code adds operational and machinery requirements for service in polar waters. The engine itself is usually a standard medium-speed or two-stroke design qualified and de-rated for the duty cycle, not a separate engine type.