Nakashima FPP 5500mm 4B

A 5.5 m diameter, four‑blade fixed‑pitch propeller made from nickel‑aluminium bronze (NiAlBz), intended for low‑speed main engines around 110 rpm to provide high thrust efficiency and durability. The supplied category identifies it as Fixed-Pitch Propeller, and it is normally installed at the aft end of the propulsion shaft outside the hull, directly converting shaft torque into propulsive thrust. In that role, its primary purpose is to provide forward or astern thrust with a blade pitch that is fixed by the propeller geometry. Unlike a controllable-pitch propeller, an FPP has no internal pitch-changing mechanism, so thrust reversal normally depends on reversing shaft rotation or another propulsion arrangement. Within the supplied list, neighbouring variants are distinguished by their model designations and naming, while the source does not state further model-specific hardware differences. No additional performance, approval or construction detail is inferred from the model code beyond the information supplied in the source record. For exact ratings, dimensions, settings, capacities, materials and variant-specific limits, refer to the manufacturer documentation for the exact figure.