It is well known that ship speed reduction leads to fuel economy. Speed can be reduced during the voyage, if the amount of time in passage can be increased or the ship itinerary could be optimized. Thus, improved itinerary and optimal voyage management are regarded as two major areas that could be used for this purpose. A ship's movement commercially is influenced by many factors, some of which are listed below:
- The requirements of the “cargo owner” (mainly shipper or charterer) on when and where the cargo should be loaded and discharged. This is normally mentioned as the most likely reason for changes to the ship operation plan, schedules and timetables.
- The slotting issue in ports in terms of berth or cargo storage availability. Early arrival and competing for early loading/discharge is common industry practice.
- Regulatory issues that may lead to delays, prevention of entry to certain ports or ship detention for some period of time. The lost time normally recovered later via over-speeding.
- Technical failures that require fixing while in port or at anchor (reduces ship availability).
- Lack of business (cargo), resulting in short or long idle periods.
Itinerary optimization, proper voyage planning and voyage execution are areas of interlink between shore managers and ship’s masters. As such, the link between the shore managers (charterer and ship operator) and the ship’s master is critical for optimal ship operation management. In practice, the simplest models of working relationship are normally established between the above parties. For example, the shore-based managers specify the ports of call and timings. In some cases, they change their orders and ship itinerary while the ship is underway. The master then decides how to move and at what speed in order to meet the above timings. Normally, the master tries to reach the port of destination as soon as possible within the contractual limits. The above processes generally lead to the following anomalies:
- Ship voyage speed is normally maximized with an early arrival at the next port.
- Total ship stay in ports and waiting in anchor is normally maximized.
This practice is not energy efficient. To make it efficient, the shore-based manager and the vessel’s master should be given the responsibility to do the opposite; maximize the sailing periods and minimise the waiting periods. Unfortunately, itinerary optimization and voyage management could easily be sacrificed by either poor planning or poor execution due to commercial and other nontechnical pressures. The improvement to ship itineraries requires efforts to be made by all the parties involved. For this purpose, the collaboration and coordination of the following bodies are essential:
- Charterer operation department: The charterer is ultimately responsible for decision making on the ship itinerary and overall steaming speed. Orders issued by the charterer to the ship are normally the basis for master’s decision on ship movement.
- Ship master: The master, based on the orders received, operates the ship and ensures that the designated dates and times are achieved; within the terms of the charter party. The master can play a major role in improving the ship itinerary via more interaction with the charterers/owner’s decision makers.
- Port authorities: The Port authorities influence the plans drawn up by both the commercial department and master through the management/planning of the port operation.
It is the interaction between the above parties that leads to the actual (achieved) ship itinerary. Better communications, coordination and awareness of the impact of their decisions on ship fuel consumption could improve operations (MariEMS 2017).