OVERHEATING OF PARASAIL VESSEL HYDRAULIC OIL SYSTEM

Vessel DocumentationCoast Guard Safety Alerts

OVERHEATING OF PARASAIL VESSEL HYDRAULIC OIL SYSTEM LEAVES PARASAILORS ALOFT FOR THREE HOURS

The information in this safety alert is derived from a recent parasail casualty investigation. Two passengers were successfully launched from a parasail vessel for a ride aloft. As they were being winched in the winds picked up. The parasail towline winch became inoperable and 800 feet of towline payed out stranding the passengers aloft. Additionally, the vessel was unable to make way through the water while battling rough seas and the strong winds.

The cause of the winch malfunction was due to overheating of the hydraulic power system. This occurred because of an inadequate oil cooling system (through hull fittings / scoop type system) that relied solely on the vessel’s movement through the water. When the vessel’s movement was overcome and stalled by the wind acting against the parasail and the waves, there was no water circulation and thus no resultant cooling of the hydraulic oil. Since there was no fail safe braking system, the towline payed out when the hydraulic motor could no longer develop power. Three hours passed before the winds subsided enough to allow forward movement of the vessel, cooling off of the oil, and restoring the system to operation.

This event was fortunate in that the parasail towline did not break and there were no fatalities or injuries. Nevertheless, to prevent similar occurrences, the Coast Guard strongly recommends that insurers, owners and operators of parasail vessels:

• Ensure their vessel’s parasail winch hydraulic oil cooling systems are not dependent on forward movement of the vessel. If necessary, have the system modified by a parasail vessel professional.

• Owners of parasail vessels which do have pressurized hydraulic oil cooling systems should ensure that their systems are properly fitted with inlet strainers on the sea water supply and that the rest of the system, pumps, motors, controls, oil filters, etc. are properly maintained at the proper frequency.

• Review the attached previously sent “Know Your Ropes” safety alert and remember:

You set the stage for passenger safety!

This safety alert is provided for informational purposes only and does not relieve any domestic or international safety, operational or material requirement. Developed by the Office of Investigations and Casualty Analysis. For questions or concerns please email hqs-pf-fldr-cg-inv@uscg.mil.