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Mitsubishi Heavy Industries Marine Machinery & Equipment Co., Ltd. (MHI-MME)

Rapson Slide Ram Type

Mitsubishi Heavy Industries Marine Machinery & Equipment Co., Ltd. (MHI-MME) Rapson Slide Ram Type — License-manufactured steering gear (mechanical actuator type).

Components & Design

Component data being added…

Technical Data

Mechanism Rapson slide crosshead (mechanical advantage increases with angle)
Actuator Ram type with reciprocating motion conversion
License agreement Jiangsu Masada Heavy Industries Co., Ltd. (February 2012)
Application Large ship steering control
Advantage Mechanical advantage increases with rudder angle

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Common failures & inspection points

Hydraulic oil contamination and degradation (most common cause of steering gear failure)

Perform oil sampling analysis every 500 operating hours minimum; check for water content (max 500 ppm per ISO 4406 standard), particle contamination (ISO cleanliness code 15/13/10 minimum), and viscosity at 40°C

Hydraulic fluid leakage from cylinders, pipes, and connections (zero tolerance policy by Port State Control)

Conduct weekly visual inspections of all hydraulic lines, connections, and cylinder seals during operation; check relief valve discharge paths are clear; verify pressure at gauge within ±5% of design specifications per IMO resolution MSC.407(97)

Steering gear performance degradation and delayed rudder response

Test rudder movement capability: verify rudder travel from -35° to +35° in less than 28 seconds at maximum loaded draft and service speed (per SOLAS II-1/29); conduct emergency steering drill every 3 months; verify control follow-up systems and non-follow-up lever engagement

Pump motor failure, control system malfunction, and electrical isolation faults

Verify pump motor starts without load; test all bridge control positions and autopilot integration before departure (within 12 hours per SOLAS II-1/26); inspect motor cabling for moisture ingress; verify electrical isolation switches and emergency stop functionality

Rudder stock bearing clearance wear, tiller arm bushing deterioration, and mechanical linkage obstruction

Measure rudder stock bearing clearance annually (tolerance 0.1-0.3 mm per ship class rules); inspect tiller arm bushings for wear; verify all mechanical connections are torqued to specification; ensure unobstructed full rudder travel with no binding or unusual noises

Type-general inspection and maintenance points for this equipment category — not model-specific.

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Equipment Model #146658 · ✓ still in production