Port costs:
The port costs are entailed at each call for port for the use of tug boats and harbor facilities and for cargo handling. These vary widely from port to port and by type of cargo. In this simulation, the cargo was assumed to be bulk cargo such as grain and plastics chips. Four ports, Yokohama, Hamburg, Dikson and Tiksi were chosen as departure/destination ports. The port costs at Yokohama and Hamburg were suggested by the NYK line and those at Dikson and Tiksi were referred from INSROP report (WP-128).
Transit fees on the Suez Canal:
The transit tolls in the Suez Canal were based on the Suez Canal Tonnage and are dependent on type of vessel and carrying capacity. The tolls were estimated by the use of the correlation data between GTs for bulk carriers and their Suez Canal tonnages.
NSR fees (transit fees):
Transit dues must be paid to pass through the NSR. These transit fees include icebreaker escort fees, which are charged per voyage and are regarded as a flat-rate fee, regardless of the frequency of icebreaker escort. In fact, the transit dues must be paid even if no ice is encountered and no icebreaker service is required. The icebreaker escort fee referenced in Table 4.4-6 was cited from the WP-128. The fee is a function of gross tonnage, ice class, season and area of operations, and is specified up to 20,000GT. The cost per GT decreases as GT increases. Surprisingly, summer fees are higher than winter fees, even though frequency of icebreaker support is obviously much higher in winter. It must be noted that final transit fees are subject to negotiation with MSC, which provides the icebreaking services, so the following table should be taken as an approximation only. The values in Table 4.4-5 are the transit fees extrapolated from Table 4.4-6 for the three ships in the simulation. The tariff rate for the 50BC is raised by 10% from the extrapolated value, taking account of the inferiority of icebreaking capability in comparison with other vessels.
Algorithms for calculating ship speed
The most important aspect of the cost simulation is the determination of ship speed under various types of ice conditions. Knowing the ship's speed makes it possible to determine how many days the vessel will be at sea from port to port, so that most of the shipping expenses can be calculated. To simplify this task, researchers have developed ways of expressing ice condition in terms of a numerical value called an ice numeral, which represents the difficulty of ice navigation. Ice numeral is a concept originally introduced in the "Arctic Ice Regime Shipping System Standards" used by CASPPR. The smaller the ice numeral is, the more difficult the ice conditions are. Under identical ice conditions, a ship with lower icebreaking performance will have a larger its ice numeral.
