Ship Speed Optimisation with Time-Varying Draft Restrictions

Elena Kelareva

CS HDR MONITORING

DATE: 2012-10-29
TIME: 13:00:00 - 13:30:00
LOCATION: NICTA - 7 London Circuit
CONTACT: JavaScript must be enabled to display this email address.

ABSTRACT:
With rising fuel prices in recent years, fuel usage can account for over half of the cost of maritime shipping, and fuel usage increases with faster speeds. There has been increased interest in ship speed optimisation to reduce shipping costs; however, none of the existing approaches have considered the effect of time-varying draft restrictions. Draft is the distance from the waterline to the bottom of the ship's keel, and many ports and shallow waterways have restrictions on the times when deep-draft ships can sail (eg. within a window around the high tide). However, existing ship speed optimisation approaches either ignore draft restrictions, or model them as constant rather than varying with the tide. We introduce time-varying draft restrictions into a ship speed optimisation problem for several ships on a fixed route, and show that consideration of draft in speed optimisation can reduce costs for draft-restricted ships compared to methods that ignore draft restrictions.

We also look at other scheduling and routing problems with time-varying action costs, and consider methods that can be generalised between these types of problems. We apply a number of methods that have been successfully used for other applications to the problems of bulk cargo port throughput optimisation and liner shipping fleet repositioning, and obtain faster calculation times for both problems than any previous method.