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Ship Repairing Time and Labour

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Document pages: 29 pages

Abstract: Ship repairing time, duration of stay of a ship in a shipyard (also a slipway or a floating dock), is a part of the routine maintenance schedule of a ship, mainly required by the classification societies and the flag states. With an interval of approximately 24 to 30 months, the regulations of both the flag state and the classification society call for a ship to carry out docking survey, intermediate survey or special survey (once in 5 years), depending on the age of the ship, in a shipyard floating dock slipway. It is mandatory to fulfil the requirements and comply with the rules and regulations for maintaining statutory certification. Ship owners and shipyards always try to reduce the repairing time to lessen the loss of income (for an owner) and maximize the annual turnover through handling more ships (for a shipyard).Labor cost is an important and sensitive issue in labor intensive industry. Ship repairing work is, by nature, labor intensive and not prone to automation. In regular ship repairing or routine maintenance of a ship, labor cost contributes the highest amount in the final invoice. This figure may go up to 70 of the total cost. This cost is directly provided by labor (man-days) utilized for the ship repairing works. Ship owners and shipyards are always very keen for lowering the man-days value. Lesser man-days can directly be translated into the lower final invoice (for the ship owner) and higher productivity (for a shipyard), which can help the shipyard to stay in a competitive market.Ship repairing time (days) related information for 600 cargo ships and ship repairing labor (man-days) related information for 50 cargo ships of various ages, sizes and types were collected from a single shipyard. A multiple linear regression model was developed and analyzed using these primary data of time and labor each. Ship repairing time was then expressed as a function of a ship’s age, deadweight, repairing works of mainly hull coating, piping, structural steel and tank coating. Similarly, ship repairing labor was then expressed as a function of a ship’s age, deadweight, type and repairing works of mainly hull coating, piping, structural steel and tank coating. “Method of least squares” was applied to estimate the regression coefficients.In this paper, the authors have made an attempt to identify the number of those independent variables that influence ship repairing time and labor (the dependent variables) and their inter-relationship. A mathematical model has been developed for both time and labor and proposed, as a guiding tool, for the decision-maker to estimate a more realistic ship repairing time and labor for ships to be under repair.

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