Wednesday, August 7, 2013
EXCESS CYLINDER OIL CAUSES
TURBOCHARGER OVERSPEED
THERE ARE SEVERAL REASONS WHY MAIN ENGINE
TURBOCHARGERS BREAK DOWN, REPORTS DENZIL STUART, BUT GARD P&I CLUB IN
NORWAY RECENTLY RECEIVED A LARGE CLAIM INVOLVING ONE OF THE MORE UNUSUAL
REASONS.
THE ENGINE IN THIS CASE (6CYL OF APPROXIMATELY
16000KW) WAS EQUIPPED WITH TWO TURBOCHARGERS, STILL COMMONLY USED BY MANY
SHIPS TODAY. THE CYLINDER OIL LUBRICATOR REQUIRED MANUAL ADJUSTMENT TO EQUATE
TO A CONSUMPTION OF BETWEEN 320-3801 PER 24H. THAT MEANS THE ENGINEER HAD TO
REDUCE THE CONSUMPTION MANUALLY IF THE ENGINE LOAD WAS REDUCED TO BELOW 75% FOR
MORE THAN FOUR HOURS.
REDUCTION IN ENGINE LOAD
DURING BAD WEATHER
THE UNDERLYING CAUSE OF THE BREAKDOWNS WAS FOUND TO BE
THE SAME IN ALL CASES. DURING NORMAL RUNNING BETWEEN 75% LOAD AND MAXIMUM
CONTINUOUS RATING (MCR) EVERYTHING WAS NORMAL. THE PROBLEM STARTED DURING
PERIODS WHEN THE ENGINE-ROOM WAS UNMANNED AND THE OFFICER ON THE BRIDGE (DUE TO
BAD WEATHER) REDUCED THE ENGINE LOAD TO LESS THAN 75% WITHOUT NOTIFYING THE
DUTY ENGINEER. THE ENGINE LOAD WAS KEPT LOW (UNDER 75%) FOR A FEW HOURS AND, AS
THE WEATHER IMPROVED, IT WAS GRADUALLY RAISED TO FULL MCR.
EXCESS CYLINDER OIL IN
EXHAUST MANIFOLD RESULTING IN FIRE
WHEN THE ENGINE WAS RUNNING ON REDUCED LOAD WITHOUT
REDUCTION OF THE CYLINDER OIL CONSUMPTION, A LOT OF THE EXCESSIVE CYLINDER OIL
ENDED UP IN THE EXHAUST CHANNEL. WHEN THE OFFICER ON THE BRIDGE INCREASED THE
LOAD IT ALSO INCREASED THE HEAT IN THE EXHAUST CHANNEL WHICH, DUE TO THE
EXCESSIVE AMOUNT OF CYLINDER OIL, STARTED A FIRE IN THE EXHAUST CHAMBER. IN
ADDITION, THIS RESULTED IN EXTREME OVERSPEED ON THE TURBOCHARGERS, WHICH VERY
OFTEN ENDED UP WITH SERIOUS DAMAGE AND TOTAL BREAKDOWN. THE END RESULT IS OFTEN
COSTLY OFF-HIRE AND OTHER LOSSES FOR THE OWNER AND ALL INVOLVED. MOST INCIDENTS
OCCUR WHEN THE ENGINE-ROOM IS UNMANNED.
LESSONS
AND THE LESSON FROM THESE BREAKDOWNS? GARD SAYS THAT
IF THE ENGINE IS BUILT IN SUCH A WAY THAT EXCESSIVE AMOUNTS OF CYLINDER OIL CAN
BE PRESENT IN THE EXHAUST CHANNEL WHEN THE LOAD IS REDUCED, ALL OFFICERS AND
ENGINEERS SHOULD BE MADE FULLY AWARE OF
THE DANGERS.
FURTHER, THE SHIP MANAGEMENT TEAM MUST ENSURE THERE
ARE CLEAR INSTRUCTIONS TO OFFICERS
ON REDUCING OR INCREASING THE ENGINE LOAD WHETHER THE ENGINE-ROOM IS MANNED OR
UNMANNED AS WELL AS IN EMERGENCIES.
WHEN THE ENGINE WAS RUNNING ON REDUCED LOAD WITHOUT
REDUCTION OF THE CYLINDER OIL CONSUMPTION, A LOT OF THE EXCESSIVE CYLINDER OIL
ENDED UP IN THE EXHAUST CHANNEL. WHEN THE OFFICER ON THE BRIDGE INCREASED THE
LOAD IT ALSO INCREASED THE HEAT IN THE EXHAUST CHANNEL WHICH, DUE TO THE
EXCESSIVE AMOUNT OF CYLINDER OIL, STARTED A FIRE IN THE EXHAUST CHAMBER. IN ADDITION, THIS RESULTED IN EXTREME OVERSPEED ON THE TURBOCHARGERS, WHICH
VERY OFTEN ENDED UP WITH SERIOUS DAMAGE AND TOTAL BREAKDOWN. THE END RESULT IS
OFTEN COSTLY OFF-HIRE AND OTHER LOSSES FOR THE OWNER AND ALL.
