Some studies have established regression functions to explain the
relationship between cost component per unit(DWT or TEU)and ship
size by employing data of ship operation from industry consultants
and CSLs.In the models of Jansson and Shneerson (1978,1987),
capital cost is estimated to conform with the two-third power rule
whereas the size elasticities of operating cost and fuel cost are
0.43 and 0.72 respectively. Talley(1990) deploys regression functions
to calculate operating and port cost.The out come implies the upward
trend of optimal size incase of fewer numbers of port calls,shorter
port time and longer ship distance. Cullinane and Khanna(1999,
2000) exclude port cost in their estimation as the argument that it
has little variation in carrying capacity.The model confirms again
benefit of ship size at sea as well as advantage of large ships on long
routes. Veldman(2009) takes into consideration economies of ships
from 6000to20,000TEUs.