Failure of AHC cylinder causing oil leak to deck

A hydraulic cylinder on an Automatic Heave Compensated crane failed. The incident occurred when an offshore vessel was engaged in the installation of a jumper line in 690m of water. The vessel was stood off at a safe distance from a drill centre; the crane was stationary at the time and waiting in AHC mode.

A bang from the crane was heard from inside the crane cab and the crane automatically switched to normal mode (AHC off). A leak was spotted from the cranes right hand side. As soon as it was observed that there was an oil leak from the bottom of the AHC cylinder the crane was stopped, and the alarm raised to contain the oil.

The client’s jumper was lost as unrecoverable. Our member noted that had the incident occurred exactly over the drill centre, major damage could have been caused to subsea assets.

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