3. Simulation code
3.1 Features and assumptions
This simulation features;
・Sufficient long-term historical environmental data to examine the trend of cost
・Short segment of 20NM to describe the route
・Service ships with much larger size to improve the cost efficiency expecting the future trend
・Reasonable relation between ice condition and ship speed
・Two type of cost descriptions to meet technical and shipping industry aspects.
Some of assumptions adopted from other work packages are already mentioned in chapter 2, although summarized as follows for clarification purpose.
Four routes are selected. Each route is plotted in every 20 nautical mile within the NSR.
Northerly route：Transit route between Yokohama and Hamburg, draft for 12.5m
Southerly route：Transit route between Yokohama and Hamburg, draft for 9.0 m
Regional East route：Rieglonal routes between Tiksi and Yokohama, draft for 9.0m
Regional west route：Regional routes between Dikson and Hamburg, draft 9.0m
Seven parameters, namely, cold sum, mean first year ice concentration, mean multi year ice concentration, mean ice thickness, floe size, mean ridge sail height and mean ridge density are used. The data are described for each 20 NM segment by month and year from 1953 to 1990.
The data are comprised of capital, crewing, maintenance, insurance, fuel, port and icebreaker escort costs as summarized in Table 2.3.1. WP4,7,and NYK line reports are referenced.
Service ships and escort icebreaker
Three service ships and newly prepared for the simulation. They are larger than existing ships and feature new propulsion system. Two of them are bulk/container ship with the capacity of 25,000DWT and 40,000DWT, and the other is bulk carrier of 50,000 DWT. Their icebreaking capabilities are confirmed by ice tank tests. Arctica class is selected as escorted icebreaker. .
Ship speed algorithms
WP6 provided sophisticated computer code capable of predicting ship velocity in ice taking account for various ice conditions. However it takes too long time to run the code in each segment. Therefore, an ice condition each segment is expressed in the form of index, and the relations between index and speed are created using WP6 code. One index gives several ice features, therefore a ship speed corresponding to arbitrary index distributes some ranges of speed. These scatter ranges are expressed in the form of discrete probability as shown from Figure 2.6.6 to 2.6.10.
Decision of icebreaker escort
Icebreaker escort is decided by referring ice index. The minimum effective ship speed