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1. Operational control
操作控制
The term operational control is used in this context to consider alternatives to technical solutions to obtain reduced greenhouse gas emissions. As the emissions are related to the consumption of fuel onboard, the various options considered will be evaluated according to influence on fuel consumption.
长期操作控制是用来在这方面考虑替代技术解决方案，以获得减少温室气体排放。由于排放量与到板载燃料消耗，考虑根据燃料消耗的影响，对各种选择进行评估。
As opposed to the evaluation of technical measures for reduction of emissions, the external factors affecting the various trades will be taken into consideration as far as possible when considering operational measures.
反对减排的技术措施的评价，各行业的外部影响因素，将尽可能考虑营运措施。
The operation of one ship or a fleet will be adjusted to the market situation. In a segment of the market, the supply and demand will correlate according to the governing market mechanisms for the segment. Based on historical data, the size of the fleet and the demand for tonnage has been found to be unbalanced for several commodities during several periods of time [Stopford, 1997].
根据历史数据，已发现的船队规模和吨位的需求，多种商品在几个周期的时间是不平衡的。
In order to consider operational control in relations to the market demand for shipping services, the productivity of the fleet may be applied as measure for considerations on how operational control may reduce fuel consumption. If it is assumed that the productivity of a fleet segment should be equal or better than the present situation, the different factors affecting the productivity may be considered from a perspective where reduced emissions is the target for improvement. This assumption is applied based on the fact that shipping supply has limited influence on the demand. One simple reason for this is that changes in supply (measured in tonnage) will have a slow variation, while demand may fluctuate rapidly as an effect of external factors. The efficiency of the fleet will in this context offer a substantial flexibility in order to adjust to variations in demand.
为了考虑以市场需求为航运服务业务控制关系，可以应用于舰队的生产力作为考虑如何操作控制可以降低油耗的措施。
Operational profile of a vessel or fleet will determine the operational efficiency in terms of transport work. The fleet productivity (P) for bulk transport may be expressed theoretically as
[Wergeland, Wijnolst, 1996] :
船只或船队的经营档案，将决定运营效率方面的运输工作。
P = f (A, CU, L, W, Bf, V)
Where
A = Active part of fleet
CU = Load factor, representing utilisation of capacity
L = Average length of haul (loaded condition)
W = Time not at sea (off-hire, loading/discharging)
Bf = Ballast factor, relative time in ballast vs. in loaded condition
V = Average speed
In the following, the various options for operational control will be discussed in accordance to their effect of reducing CHG emissions.
在下文中，按照减少CHG排放效果，将要讨论用于操作控制的各种选择。
Choice of speed
速度的选择
For a given ship in a given condition, the fuel oil consumption, and thus the greenhouse gas
(GHG http://www.ukassignment.org/uklunwen/ ) emission, will mainly be a function of the ship speed. The fuel consumption per distance sailed will approximately increase proportionally with (at least) the square of the speed.
对于一个船舶，在一个给定的条件下，燃油消耗和温室气体（GHG）排放，主要是船只的速度函数。
Limitations on speed selection
速度选择的限制
From the ship owner's point of view, planning of both fleet operation as well as the speed of each ship will be selected from economical considerations, dependent of the present and expected market situation (fleet planning is further discussed later on).
从船东的角度来看，规划的两个车队运作以及每艘船的速度，将从经济考虑选择，取决于当前和预期的市场情况（机队规划中进一步讨论）。
Optimal speed, from an economical point of view, may be defined as the speed that maximizes the difference between income and expenses (per time unit) of the ship. Models for determination of optimal speed of a ship can for instance be found in [Ronen, 1982].
最优化的速度，从经济观点看，可以定义为速度，最大限度地提高收入和支出（每单位时间）之间的差异.
“Optimal speed", however, will not necessarily be identical as seen from the view of different participants in the transport chain. The cargo owner will normally consider the value of his cargo and the time of port arrival in relation to the transport cost. The ship owner must evaluate his income and costs, normally given by a contract. Contract forms and chartering conditions, however, will vary between different trades.
然而，“最优速度”，运输链中的不同参与者的看法不一定是相同的。货主通常会考虑他的货物抵达港口有关的运输成本和时间价值。
In a market with excess capacity of tonnage compared with the cargoes available, slow steaming can be favourable. However, before implementing "slow steaming", service level demands from the cargo owner must also be considered.
然而，在实施“慢蒸”时，货主服务水平的需求也必须被考虑。
If the "optimal speed" (from an economical point of view) is close to the maximum speed of the ship (in a favourable market), the ship owner will normally select a "minimum time" strategy for the ship. In this case the ship will be operated at highest possible speed (only limited by technical and safety factors). To limit the ship speed in this case from an ecological point of view, this may only be achieved by means of law imposed speed limitations or penalty tax in relation to a high fuel consumption level.
从生态的角度来看，在这种情况下，限制了船的速度，这可能只可通过法律手段，关系到一个高油耗水平速度的限制或惩罚税征收实现。
If the optimal speed of the ship is lower than the maximum speed of the ship, the ship owner may select a "Just in time" or "Slow Steaming" strategy. In this case the ship will be operated at a reduced speed. From an economical point of view, slow steaming is normally of interest only if the number of ships, and then transport capacity, is high in relation to a given market.
如果最优的船舶速度低于最高速度的船舶，船东可能会选择“时间”或“慢蒸”的策略。在这种情况下，船舶将降低速度。
For most ship engines, running at reduced speed / slow steaming may, however, cause problems. Such problems may be vibrations (critical RPM of engine / shaft) and accelerating sooting in the exhausted gas channel. Sooting problems are normally coincident with incomplete combustion and increasing GHG emission per fuel unit consumed. For ships permanently operating at slow speed, however, engine modifications / de-rating may be a solution.
然而，对于大多数船舶发动机，在降低速度/运行5个月时，会造成问题。这样的问题可能是振动（临界转速发动机/轴）和加速积碳废气通道。
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