278.F期间费用的核算与控制探讨 外文原文.doc

A cross sectional analysis of ship maintenance expensesByGeorge C. Bitros and Manolis G. KavussanosAbstractThis paper introduces an econometric model to explain the determinants of expenditure in ship maintenance and repair. The data refer to 112 vessels of different types that operated in 1999 and were collected from ten Greek ship owning and management companies. On the methodological plain the best functional form is obtained when estimating a semi log-linear model.As expected from theory, the empirical results show that maintenance expenditure is positively related to utilization, age, and size. In addition the effect of age is found to be stronger on vessels younger than 20 years. This may be due to the fact that vessels less than 20 years old can be sold more easily in the second-hand market, whereas older vessels have a shorter lifetime and are also constrained by safety regulations. Therefore, ship owners are more reluctant to spend more once the vessel passes its 4th and especially its 5th special survey. To trace the effect of company policies we included in the model company dummy variables. We found that such effects are present particularly when stores expenses are estimated separately. In turn, this suggested that company policies have still some control on maintenance expenses. Another result is that the elasticities of maintenance expenses with respect to utilization, age, and size at least in 1999 were uniformly less than one, thus revealing the existence of significant economies of scale. And still another result is that the type of ship, the flag, the classification and even the yard where maintenance takes place are significant determinants of the respective outlays.1. IntroductionShip owning and management companies are facing new pressures and challenges inprocuring an effective and cost efficient maintenance schedule. During the 90s a new stream of regulations and the increasing activity of State Port Authorities in ensuring that visiting vessels satisfy their seaworthiness certificates changed the perception on how ship maintenance should be dealt. Indeed, the new policy trend towards eliminating substandard ships aims at improving seaworthiness and at raising the quality and quantity as well as the frequency of maintenance.Overhauling, in terms of major surveys, is no longer perceived to be the only means of maintenance but rather regular maintenance is required to be preventive in nature and allow for upgrading the equipment and condition of the vessel. Thus, understanding which factors contribute in what way and by how much towards maintenance effectiveness may assist managers optimize the allocation of respective resources in their efforts to determine the useful lives of their vessels, and thus, to an extent, their policies regarding fleet composition.The literature to which we could turn for helpful leads in our research focuses mainly on the theory of scrapping and replacement and much less on utilisation, maintenance and the other decisions pertaining to ships in particular and to equipment in general. Recently Jin and Kite-Powel (1999) studied the issue of fleet renewal and found that ship replacement and ship operatingdecisions are taken jointly so as to permit maximum fleet utilisation. But they did not payattention to maintenance. A decade earlier Evans (1989) analysed the problem of ship replacement under technological obsolescence and ship modifications, but without considering theissues that are associated with ship utilisation and maintenance. At about the same time Ye(1990) investigated equipment replacement with emphasis on the stochastic nature of maintenance and operating costs, but without allowing explicitly for the intricate interrelatedness of policies regarding utilization, maintenance and scrapping. In short, by concentrating on a few of the relevant decisions and ignoring the rest, all specialised and general purpose literature has adopted a partial equilibrium approach to study a problem, which is essentially general equilibrium in nature. For this reason the model that came closer to serving our research objectives is the one that has evolved from the contributions by Bitros (1976a, 1976b, 2004) and Bitros and Flytzanis (2002, 2003, 2004).On the theoretical plain, the estimated model took a semi log-linear form and fitted well the observations. No matter how the data were segmented the estimates highlighted three key factors that explained total ship maintenance expenses in 1999. These were the age, the size and the utilisation of ships. In addition we estimated the effect on maintenance for vessels under 20 years old and for each type of vessel in the sample. The results confirm Frankels (1991) findings2.1 A brief note on ship maintenance policies and regulationsIn the period before the introduction of the International Safety Management Code(ISMC), ship owners opted usually for a “breakdown” policy. In other words, all equipment would be lubricated and operated with care, yet no maintenance would take place until equipment would break down and it would require repairs or complete change of spares. This policy led to substandard vessels and coincided with a number of prominent shipping accidents (e.g. Exxon Valdez). As a result policy makers changed attitudes on how shipping maintenance should be done. The imposition of the ISMC and the increasing number of Port State Controls havechanged the disposition of shipping companies with respect the maintenance of ships. Nowadays any ISMC certified shipping company is obliged to carry a planned maintenance policy. Although some may be more organized than other shipping companies, the preventive nature of the new regulations imposes higher maintenance cost for all companies. In addition, the fact that planned maintenance work requires stricter control and existence of records has led to more frequent maintenance rather than postponing it until the next intermediate and special survey. ICS/ISF2 suggest that preventive maintenance policies be established for the non-exhaustive list of ship components shown in the Table 2.1. Actually the ISMC does not recommend an infrequent maintenance policy, but it imposes a continuous assessment of the vessels condition and requires immediate action by the shipping company to remedy any system fault or malfunctioning. Lastly, the increasing number of Port State Controls and Detentions of vessels hasobliged ship owners to be very careful on keeping good track maintenance records and to detect possible maintenance work before the ship entering a strict port on safety issues. Therefore,whenever it is practically feasible, ship companies increase maintenance work during a ship voyage,Table 2.1: Ship components for preventive maintenance as suggested by ICS/ISFin particular when the vessel is on ballast, to avoid potential detentions in ports. The potential risk of a vessel being detained has huge commercial as well as legal and insurance implications since these are reported and may affect the vessels cash flows in terms of income and insurance premia, which will have to pay for a substandard vessel.2.2. From the theoretical to the estimating modelHaving extra crew on board to undertake maintenance work may increase directly maintenance expenditure. However, if the maintenance is postponed, it may result in higher future maintenance outlays (higher dry-docking bills) and foregone earnings. Hence the relationship of crew on board and maintenance expenditure is not straightforward. In addition, the composition of the in terms of different nationalities does not impose any a priori expectation, since all crew carry internationally equivalent certificates. To be sure there are wage differences among different crew nationalities and possibly different productivity levels. But a more productive crew may pay more attention to maintenance, thus raising current maintenance outlays but potentially reducing the risk of unexpected higher maintenance bills in the future.2.2.2 Type of vesselVessel type is expected to be a significant factor because different vessel types imply that operational procedures may have an impact on the vessels wear and tear and result in a wide spectrum of maintenance expenses among all types of vessels. Usually, containerships, gas carriers like Liquefied Petroleum Gas (LPG), Liquefied Natural Gas (LNG), and Ro-Ro vessels are committed in haul trades that require them to operate at high speeds so as to meet their time schedule targets. Moreover, the high number of ports visited per year and the higher frequency of charging and discharging, leads to higher levels of physical stress of the vessel. Tramp ships on the other hand, are more flexible in terms of adjusting their speed, since the latter depends on the conditions prevailing in the freight market, ship managers of tramp vessels may consider more carefully whether to accept a shipment. Factors such as where to charge/discharge are considered carefully since the benefit from the freight may not always compensate the risk of damaging the vessel in a substandard terminal, especially when cargoes like iron ore can damage significantly the vessels cargo hulls. In sum, it is expected that LPGs that use sophisticated technology for the safe transportation of gas products to exhibit higher maintenance expenses than simpler types of vessels.2.2.3 FlagChoosing a Flag may enable a ship owner to avoid expenses since countries with therespective flags set regulations on maintenance, nationality of crew, and safety conditions. Liand Wonham (1999) undertook a study on the safety records in terms of accidental total loss rates of thirty-six world principal fleets using twenty years of data. Their study confirmed that open registered ships tend towards substandard ships. In addition the study showed that the developing country fleets performed better than those of developed countries, although some of the former flags had performed much worse than the average. Therefore, choosing a flag may affect maintenance policy, and condition a vessels seaworthiness record. For example,Panama was recorded in the above-mentioned study as one of the worst flags in terms of safety grounds. The Drewry report (1999) shows a summary of the Australian Maritime Safety Authority port state control inspection in Australia and 29% of the ships inspected were registered with Panama. It may be that port authorities get more suspicious with flags that have a worse reputation relative to than others. Interestingly, however, while Singapore was rated better than Panama in the above study, the highest percentage of ships detained were not those with Panama flags but those with Singaporean flags, since 10% of the latter were detained as opposed to 6% of the former.Eventually the ship maintenance rules imposed ISMC scheme, as well as the increasing number of port state controls, may vitiate the influence of flag on the respective expenditures.This is likely to happen because, although there are still some flags from developing countries for which the ISMC rules are relatively laxed, shipping companies are obliged to pay increasing attention to safety issues, irrespective of their vessels flag. But in 1999 the flag factor was present and should be included in the set of explanatory variables.2.2.4 The ships constructionFactors such as the ships original construction may affect subsequent maintenance requirements. If epoxy coating was applied on cargo and ballast tanks when the vessel was built it may bring long lasting benefits because it protects the vessel from the early corrosion on its surface.In addition, a series of vessels built with high tensile steel technology resulted in higher maintenance demands. High tensile steel is thinner and resulted in higher future steel replacements as a result of extensive corrosion on vessels hull superstructure. It is expected that vessels built with high tensile steel require higher maintenance expenditures. In particular, one should test if the specific repairs and survey expenses are positively related to this factor.2.2.5 ClassClassification Societies play a role in assessing the vessels seaworthiness. Accordingto Stopford (1999) the main job of classification societies is to enhance the safety of life and property at sea by securing high technical standards of design, manufacture, construction,and maintenance of mercantile and non-mercantile shipping. It is the classification societies that have imposed the obligatory intermediate and special surveys. These class requirements set the general regulation for classing existing vessel. Each society, nevertheless, can extend its requirements and set even stricter rules. For example, Lloyds Register3 imposes a hull and machinery special survey-every five years-, dry-docking-every 2 and a half years- annual hull and machinery surveys, tail shaft inspection every five years-, and boiler survey-every two and a half years. Clearly, there are implications related to the ships insurance cover, because a classed vessel faces reduced insurance premiums. However, there has always been controversy in cases where classed ships were detained by the Port Authorities or had a serious accident because of faulty maintenance. For these reasons it is difficult to form an a priori expectation for the relationship between class and maintenance expenditures.2.2.6 Location and yard for maintenance workAnother characteristic in a vessels trading pattern is that it may condition the location of yard for the intermediate or special survey. Containerships are very limited in choosing the cheapest yards because they are committed in fixed routes and on tight schedules. As they provide a continuous service, container companies are very careful in planning the next surveys of their fleet. Any time delay may hamper the reputation of the company and fierce competition may take over its services. It is not uncommon for most containers to dry-dock in a yard where they offer services, in order to avoid travelling from one point of the world to another and cancel its scheduled trips. The selection of where to do the special survey or intermediate survey becomes equally important to all shipping companies since these can considerably affect maintenance cost. It is true that tramp shipping is favoured in this aspect since bulk carriers and tankers have a greater choice among yards. Since all companies must undertake the special survey and intermediate survey every 5 and 2 ½ years, the choice of yard makes a great difference in costs.The most competitive yards are in Far East Asia, such Singapore, and China. However, it is not the purpose of this dissertation to list the factors that affect the decision where to dry-dock, but one point that should be mentioned is the following. The shipping market