Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering
Transport Technology

B.C. Bührmann Chemicaliëntransport in de 21ste eeuw.
Computer program, Report 2003.TL.6746, Transport Engineering and Logistics.

During a portcall, a parceltanker visits several terminals (average: four terminals) to load or discharge chemicals. These chemicals can be transhipped to a tank at a terminal or to another vessel, a barge or a coaster. Due to a poor organisation of the transportation and different interests between terminal operators and shipowners parceltankers stay in port for a long time (average nine days), which affects the profitability of the parceltankers in a negative way.
Loading and discharging the parceltanker at one location only (central terminal) can reduce porttime. The cargo that has a terminal as the final destination is transhipped into a smaller vessel and transported to the terminal. These actions result in extra costs, because of the extra transhipment, transport and cleaning of tanks. On the other end the yearly profits of a parceltanker could rise, as the porttime of the parceltankers is reduced to a couple of days. The model described in this report determines whether the extra profits counterbalance the extra cost for transportation. Although the model can be used for al kinds of parceltankers, ports and liner services, there has been chosen for one of the largest parceltankers (37.015 dwt), which runs a weekly service between Houston and Rotterdam.

Model on port level
The model consists of two levels for calculations, port level and chain level. First of all the costs of a stay in port are calculated with the model on port level. Three concepts are developed for the transhipment of chemicals (see figure 0-1):

Figure 0-1: Three used concepts

  1. Multiterminal: the parceltanker visits 4 terminals and stays in port for 9 days
  2. Hub & Flatting: the parceltanker visits the central terminal only and stays at the terminal for 2 days
  3. Hub & Flatting + 1 terminal: the parceltanker visits the central terminal and is shifted to another terminal to tranship a big amount of cargo and stays in port for three days.
In figure 0-3 the results are given for the model on port level. The results show the different kind of costs during a stay in the port of Rotterdam.

Figure 0-2: Portcosts per concept

Model on chain level
To determine the consequences of a shorter stay in port on the profitability of the parceltankers the model is extended to chain level. The three different concepts are employed on the ports of Houston and Rotterdam, between which a service is held with weekly departures. A combination of two concepts forms a scenario a total six scenarios are possible. Scenarios 2 till 6 are compared with scenario 1, which represents the present situation of the transportation of chemicals.

Figure 0-3: Six scenarios

The physical results are calculated for each scenario before the financial results are given. The physical results consist of the percentage porttime, the amount of parceltankers needed to run the liner service and the yearly amount of departures for every parceltanker. The financial results are given for each departure of a parceltanker, for every single parceltanker and for the liner service in total. It seems that with a shorter stay in port less parceltankers are needed to run the liner service. The parceltankers that remain can be used in other regions. The model is based on a new liner service. The savings on the depreciation costs are added to the result (see figure 0-4).
The results of the scenarios, where parceltankers are transhipped at a central terminal in both ports, hardly differ and are much better than the result in the present situation.

Figure 0-4: Result liner service with the influence of less parceltankers

Sensitivity analysis
It is expected that in the future the percentage of direct transhipment to another vessel will rise. Therefore there has been checked what the consequences of this affect are in the future. As expected the implementation of a central terminal shows better results, because less cargo has to be transported extra. The use of smaller parceltankers could reduce the differences between scenario 2 till 6 and the present situation if the occupancy rate of the parceltankers increases. A liner service between two ports (Rotterdam and Singapore) that are situated further away from each other, also reduces the differences between the scenarios. Finally the model is tested for the situation, where transhipping equipment is taken from the parceltankers and placed at the central terminal. The results give reason for further research.

The model used for calculations on port level shows that the implementation of a central terminal saves costs during a stay in a port. On chain level the model shows that the profitability of parceltankers rises.

Reports on Transport Engineering and Logistics (in Dutch)
Modified: 2003.11.29; , TU Delft / 3mE / TT / LT.