CJR Custom Propellers

CJR Propellers are custom fixed-pitch marine propellers designed and manufactured for each specific vessel using CFD and FEA design, pattern-less moulding and five-axis CNC machining. All can be made to any classification society rules, including IACS societies, and are inspected to ISO 484 Class S.

Design and manufacture

• Optional full propulsion analysis: hull resistance prediction, propulsive factors, gear ratio selection and CFD flow analysis under the hull
• Robot-machined sand/resin moulds for one-off propellers; patterns for series production
• In-house casting and CAD/CAM machining of propellers, P-brackets and rudders
• Digital inspection of geometry, skew, rake and pitch; full material traceability
• Rapid turnaround service: optimised Class S propellers up to 1500 mm diameter in 14 days or less

Propeller ranges

• Nautica – lower-speed vessels: fishing boats, trawlers, sailing yachts, displacement motor yachts, survey vessels
• MRK Revolution – minimal noise and vibration at 20–30 knots; large luxury yachts, semi-displacement and planing motorboats
• Billfish – high-speed sportfish boats up to 45 knots, with good backdown performance
• MRK Superprop – high-speed craft of 32 knots plus, production yachts and patrol craft
• MRK Pilot – workboats, especially pilot boats, with controlled cavitation erosion

Results

Customers report fuel savings of up to 10% per year and top speed gains of up to two knots when switching from hand-finished to fully CNC-machined CJR propellers.