Anchor windlasses, mooring winches, cargo cranes, steering gear and lifeboat davits all move with oil under pressure. When the hydraulics are healthy nobody notices them. When they are not, a vessel can miss a berth, lose a lifting operation, or worse, injure someone. The good news is that hydraulic systems usually warn you before they fail.

Hydraulic anchor windlass and mooring winch with chain and hoses on a ship's forecastle deck

Seven warning signs

Slow or jerky movement. A winch that hauls slower than it used to, or a crane that hesitates, often points to a worn pump, internal leakage or air in the system.
Rising oil temperature. Overheating shortens seal life and thins the oil. Check coolers, oil level and the load the system is running under.
Noise. Whining or knocking from a pump can indicate cavitation, a blocked suction line or low oil. Do not run it and hope.
Dirty or milky oil. Dark, gritty or cloudy oil means contamination by particles or water. Contamination is one of the most common causes of hydraulic wear, so oil sampling and filter changes are not optional extras.
Leaks and weeping fittings. Small drips at hoses, unions and cylinder rods are early signs of seal or hose wear. Old hoses should be replaced on a schedule, not only when they burst.
Pressure that will not hold. A brake, lock or lifting cylinder that creeps down under load may have a failing valve, seal or accumulator. On lifting and launching equipment this is a safety issue, not a nuisance.
Corroded or seized safety devices. Interlocks, limit switches, relief valves and brakes must move freely. The MAIB report into a lifeboat that fell from a davit found a heavily corroded interlock on equipment where maintenance had been suspended, as summarised by IIMS.

Why this matters more in 2026

Amendments to the LSA Code in force since 1 January 2026 set limits on the lowering speed of survival craft and rescue boats. Lowering speed on a hydraulic davit depends on flow control, relief settings and brake condition, so a healthy hydraulic circuit is part of meeting the standard. We cover the wider changes in our article on the 2026 LSA Code amendments.

What planned maintenance should include

Regular oil analysis, filter element changes and reservoir checks.
Hose inspection with defined replacement intervals, and protection against chafing.
Accumulator pre-charge checks and relief valve verification.
Function and load tests of cranes, winches and launching appliances, with results recorded.
Greasing and freeing of brakes, interlocks, pins and sheaves.

Onboard repair, so the ship keeps trading

Berth Marine repairs hydraulic systems, winches, windlasses, bow thrusters and deck machinery onboard, and combines repair with spare parts supply so you deal with one team. Have a look at our crane inspection and repair service, or send us the vessel, port and symptoms. For urgent onboard problems, we are available around the clock.

General guidance only. Follow the equipment manufacturer’s manuals and your class society’s requirements.