Vessel lost lube oil pressure, causing the main engine to go off line.
Vessel was sailing with pilot on board in vicinity of Big Stone
Anchorage when a failure occured in the main engine,
forcing the vessel to anchor.
The failure was a result of a loss of lube oil pressure in
the main engine.
This caused the automatic stop of the engines.
Investigation revealed an internal leak in the No. 1 + No. 5 pistons.
Both pistons were changed out.
Recommend case be closed to file with no further action taken by this office.