Hydraulic systems play a crucial role in many small to medium-sized yachts and pleasure boats, powering steering, trim tabs, thrusters, stabilizers, and even lifting platforms or davits. While hydraulics offer power and reliability, they also require regular maintenance to prevent leaks, failures, and costly repairs.
Common Hydraulic Systems on Small to Medium Yachts
Hydraulic Steering – Found in most yachts over 30 feet, providing smoother and more reliable control than mechanical cable steering.
Trim Tabs & Interceptors – Adjust hull trim for better fuel efficiency and handling.
Cranes – Loading dinghies, jet skis and other heavy items.
Passeralle – Sometimes called a gangway or boarding ladder, found on larger boats, providing easy access from a marina or dock.
Tender Lifts & Davits – Hydraulic lifts for launching and retrieving dinghies or tenders.
Stabilizers – On larger boats, hydraulic fins or gyro systems reduce rolling motion.
Swim Platforms – Becoming very popular on catamaran's, a water level beach that stows at deck level for travelling.
Common Hydraulic Problems & Failures
Hydraulic systems are reliable, but when they fail, it’s often due to one of the following issues:
Leaks – The most common problem, caused by worn seals, loose fittings, or cracked hoses. Even small leaks can reduce pressure and cause system failure.
Air in the System – Air bubbles reduce efficiency and cause spongy or unresponsive controls (common in steering).
Contaminated or Degraded Hydraulic Fluid – Old or dirty fluid leads to increased wear, damaged or leaky seals, jamming control valves and total failures.
Hose Deterioration – Hydraulic hoses wear out over time due to pressure cycling, UV exposure, and saltwater corrosion.
Pump or Motor Failures – Pumps can fail due to overheating, lack of lubrication, or internal wear.
Sticking Valves or Actuators – If a hydraulic cylinder or valve becomes stuck, trim tabs, stabilizers, or steering may not respond properly. This is usually due to old or contaminated hydraulic fluid.
Hydraulic System Repairs
If a hydraulic system fails, follow these steps:
Check for Leaks – Look for oil spots in the bilge or around hydraulic fittings.
Change the hydraulic oil – Open hydraulic systems, those that have a tank, absorb salt air and moisture which will damage seals as well as metal parts.
Bleed the System – If steering or trim tabs feel spongy, air may be trapped. Follow the manufacturer’s bleeding procedure.
Top Up or Replace Hydraulic Fluid – Always use the correct marine-grade hydraulic oil recommended by the manufacturer.
Inspect & Replace Hoses or Seals – If you find leaks or cracks, replace affected hoses and fittings.
Check the Pump & Valves – Ensure the pump is operating correctly and that solenoid valves are functioning.
Preventative Maintenance Tips
Check Fluid Levels Monthly – Low fluid levels can indicate leaks and lead to system failure.
Change Hydraulic Fluid Every 2-3 Years – Old, contaminated fluid accelerates wear and can clog pumps and valves.
Inspect Hoses & Fittings Annually – Look for cracks, corrosion, and signs of chafing.
Bleed Steering Systems Regularly – Especially important after repairs or refilling.
Flush & Replace Seals on High-Use Systems – Hydraulic rams and actuators on stabilizers, trim tabs, and thrusters need periodic rebuilds.
Keep a Spare Hydraulic Hose & Fluid Onboard – A quick repair can prevent major issues at sea.
Final Thoughts
Hydraulic systems make boating easier and more comfortable, but neglecting maintenance can lead to costly failures. Regular inspections, fluid changes, and leak checks can keep your system in top condition.
Would you like recommendations on specific hydraulic fluid types or tools for onboard repairs? Give us a call or drop in to our Ocean Marina Jomtien store.
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