How a Shop Trial Data Helped to Save Millions of Dollars!



Image credit: Bluebird

Few years back technical Superintendent of one of the shipping company referred one very unusual phenomena of one of the two main engines fitted on board Multi Support Vessel under their management.

The vessel was in dry dock for it’s routine cycle inspection.  Prior to coming for lay up the   Chief Engineer reported to the company that whenever the STBD M.E. is started from the Bridge Control, the engine starts; however within matter of minutes it gradually slows down & ultimately stops.

The Superintendent called in their regular contractor to carry out complete overhauling of the engine.  However it did not prove any success.  Hence the matter was referred to O.E.M. who took the responsibility of setting the things right.  However no success.  Hence O.E.M. suspected something wrong with the gear box.

The Superintendent therefore asked Engine O.E.M. to investigate their suspicion regarding malfunctioning of gear box and set the things right.  Even after overhauling the complete gear box by O.E.M. the engine did not respond.  The O.E.M then suspected probable fault underlying in C.P.P. mechanism of the propeller shafting & suggested to Superintendent to open up the C.P.P. mechanism since they found nothing wrong either with the engine or gear box.  This was the time that experts were called in to withdraw the C.P. shaft.  Upon superficial inspection of the C.P.P shafting from the engine room & also from the dry dock area the experts felt there should be nothing wrong with the C.P.P. shafting since there were no traces of stern tube oil leakages both inside and outside and stern gravity tank  maintaining it’s level.  Also the actuator of C.P. mechanism responding well.  Hence asked Chief Engineer of the vessel the exact sequence & what actually happens with the engine when engine is started from the Bridge Control.  The Chief Engineer narrated his version.

The experts asked Chief Engineer whether the engine shop trial data is on board & if it can be handed over to them to study various engine parameters while the engine in operation.  We copied all parameters from the vessel’s shop trial data & after studying overnight, asked Chief Engineer the following day to start engine from the engine control stand.  During eight to ten times trying out engine with engine stalling at each attempt we succeeded in collecting the entire parameters appearing in original shop trial data & while comparing the two, found excessive disparity in the figures of temperature at the air intake manifold (formula P1V1/T1 = P2V2/T2) .

The experts suspected something wrong with the exhaust gas silencer and therefore asked the attending Superintendent to open up the inspection covers of the silencer manifold wherein they noticed that the silencer was fully choked preventing the engine exhaust gasses a free flow passage into atmosphere.

Asked Superintendent to thoroughly clean the silencer & call us back before further attempt to start the engine.

After cleaning of the silencer was over the engine was tried from Bridge Control Station & found engine spontaneously responding to the control signals.  All parameters, both pressures & temperatures were checked & compared with shop trial data & found all figures matching in close proximity.

The Owners saved hefty sum of expenditure by avoiding withdrawal of C.P. shaft.  All the same they had unnecessarily spent ten times more by opening & overhauling engine twice & also overhauling of gear box.


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The experts who solved the above problem were from Martek Engineering Works – under the leadership of Mr. Suresh V Godbole.

About the Author:

Mr. Suresh V Godbole


Steam & Motor 1st Class M.O.T. Certificate, C.Engr., F.I Mar. E C.E.O Marine Management Services Pvt. Ltd., Martek Engineering Works, Marman Engineering & Shipbuilding Pvt. Ltd.,

Passed out from D.M.E.T. in the year 1961 after completing 4 years course in Marine Engineering between 1957- 61.Commenced sea carrier joining The Great Eastern Shipping as Junior Engineer.

Bid Good Bye to sea carrier in the year 1971 after having served as Chief Engineer for 5 years.  Sailed both on Motor as well as on Steam ships.  Had an opportunity to closely observe New Building Construction as well as repair techniques adopted in Japanese Yards. Stepped ashore to start a new concept of repairs by FLYING SQUADS.  Impressed by our work technique, the local service station engineer of Burmeister & wain arranged a special training programme for self at their Copenhagen works in the year 1974.  Over the years built up the strength of our repair team by regular technical inputs to enhance their knowledge to keep up with latest innovations in repair techniques.  Today we are 45 years old & proud to say that the leading Ship Owners & Technical Managers consider us as dependable work force.

Disclaimer: The image used in this article is for representation purpose only. The opinions expressed here are author’s own and not necessarily MFAME’s prespective.


    • Dear Supt. Wang,

      Thank you for the comment. By the silencers, the author mean the one which is fitten on the exhaust trunking to the funnel to reduce the high pitch noise from the engines. This is typically located just below the ship’s funnel inside the engine room – in most cases, positioned vertically on the exhaust passage.



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