Cu1/Cu3/Cu4: Performance Differences And Selection Guide For Core Materials Of Marine Propellers
Dec 26, 2025
For marine propellers, material selection directly determines the equipment's durability, efficiency and applicable scenarios. As a factory specializing in customized marine propellers, our core materials - Cu1, Cu3 and Cu4 - are differentiated solutions tailored to different ship types and operating environments.
1. Comparison of Basic Material Properties
| Material | Core Composition | Density (g/cm³) | Tensile Strength (MPa) | Corrosion Resistance | Application Scenarios |
|---|---|---|---|---|---|
| Cu1 | Copper-zinc-tin alloy | 8.4~8.6 | 280~320 | Moderate (freshwater/low-salinity seawater) | Inland water cargo ships, small fishing vessels (cost priority) |
| Cu3 | Copper-aluminum-iron alloy | 7.8~8.0 | 350~400 | Good (coastal/medium-corrosion environments) | Coastal fishing boats, small passenger ships (balance between performance and cost) |
| Cu4 | Copper-nickel-manganese alloy | 8.2~8.5 | 420~480 | Excellent (offshore/high-salt-spray environments) | Offshore cargo ships, high-speed vessels (high durability requirements) |
2. Scenario-based Selection Logic
Choose Cu1 for inland water vessels: The corrosion risk in freshwater environments is low. The low cost and basic strength of Cu1 are sufficient to support the operational needs of shallow inland water areas. It is suitable for the batch customization of small-sized propellers ranging from 2 to 5 meters.
Choose Cu3 for coastal vessels: The salinity in coastal waters is moderate. The aluminum element in Cu3 enhances corrosion resistance, and its density is slightly lower than that of Cu1, which can reduce the self-weight of the propeller while ensuring strength. It is suitable for propellers ranging from 5 to 8 meters.
Choose Cu4 for offshore/high-speed vessels: Under the dual wear of high salt spray and high-speed operation in offshore areas, the nickel-manganese components in Cu4 greatly improve wear and corrosion resistance. Even for large-sized propellers ranging from 8 to 12 meters, they can maintain hydrodynamic efficiency for a long time.
3. Advantages of Factory Customization Services
We support full-size customization (2m~12m) based on Cu1/Cu3/Cu4 materials. We can accurately match the material, size and pitch parameters according to the main engine power and operating waters of the vessel. Meanwhile, we provide material inspection reports and after-sales maintenance suggestions.