RINA Approved Cu3 Bronze Propellers | 4/5 Blades For Ocean-Going Vessel Propulsion

We specialize in manufacturing fixed-pitch propellers with 4 or 5 blades, crafted from high-performance Cu3 aluminium bronze. Our full product range has obtained factory and product certification from RINA, Italy, complying strictly with RINA's marine specification requirements.

Our product portfolio covers standard sizes ranging from 1,550mm to 3,800mm in diameter, and we are capable of custom-manufacturing oversized propellers up to 7,000mm maximum diameter. Our products are widely fitted for ocean-going cargo ships, offshore engineering vessels, ocean tugs and large marine engineering units, fully supporting vessel procurement and classification survey for all RINA-classed ships worldwide.

Raw materials are sourced from certified qualified suppliers, with batch-by-batch spectroscopic composition inspection upon incoming delivery; any unqualified stock is quarantined and rejected to secure raw material quality from the very beginning. We adopt intermediate-frequency melting plus vacuum degassing technology to precisely control melting temperature and alloy formulation, effectively removing trapped gas and inclusions from molten bronze and minimizing casting defects such as porosity and shrinkage. All castings are produced via loam sand moulding against physical patterns, with mechanical test coupons cast alongside every heat for mechanical property verification. Full production records are filed to enable full traceability from raw material to finished unit.

All castings go through standardized heat treatment to eliminate casting internal stress and boost material ductility and fatigue resistance under seawater service conditions. Defect repair is managed in accordance with blade stress zoning; repair welding is stringently restricted on critical high-load areas, and all repaired sections require supplementary non-destructive re-inspection. After rough machining, high-stress zones including boss and blade root fillets undergo 100% PT and UT non-destructive testing in line with RINA acceptance criteria to eliminate hidden surface and internal flaws.

Finished propellers are dimensionally inspected with professional measuring equipment to check pitch, blade thickness and blade profile across all radial sections. All units pass static balance test, while high-revolution variants undergo additional dynamic balance inspection. Blades are finely polished followed by anti-corrosion passivation treatment to enhance resistance against seawater corrosion and cavitation erosion.

Backed by valid RINA certification, every finished propeller is supplied with complete documentation including material certificate, NDT report, dimensional and balance test record to facilitate smooth classification survey for shipyards. With decades of experience in large-size propeller casting, we provide custom solutions for standard and non-standard 4/5-blade configurations, earning long-term trust from global shipowners and shipyards with consistent reliable quality.