Offshore Transport System
Authors: de Vos Henny , Bos A.J. , Van Den Hoonaard A.H. , de Hemmeter Doug 
Published: October 2008

ABSTRACT
Within the research project 'Offshore Transport System' several tools have been developed to increase efficiency in transportation of men and material to offshore locations. Algorithms have been designed for: transportation of men transportation of material inventory control fleet optimization.
Use of the algorithms for transportation can result in considerable large cost savings. Further improvements can be achieved when operators co-operate in transportation.
Inventory control leads to an efficient treatment of enquiries, orders and deliveries. There is more insight in usage of materials and material flows can be predicted better.

INTRODUCTION
The research project 'Offshore Transport System' started with the objective to design and test means of transport and transfer for men and materials at sea ([1],[2]).
In order to be able to design such a system, transportation flows had to be described. However there is not much insight in these transportation flows. Therefore it was necessary to change the character of the study into a more logistic one and focus on efficient transportation with regular means of transportation. Hence first solve the economic problem and determine the design criteria for transport, where after transshipment techniques will be involved.

OBJECTIVE
The objective of the project was to develop procedures to improve the integrated transportation of men and material to offshore locations. The procedures are developed and tested for the North Sea (Dutch continental shelf).
It was studied how the procedures can be applied in other geographical areas.

IMPROVEMENTS OF SUPPLY
Bottle-necks in supply are:limited storing facility on board of the platformsdelivery dates of ordered materials determine departure times of the vesselsenvironmental conditions, influencing the planningthe fact that every operator has an overcapacity of supply capacity to anticipate on stock-outslong term forecasts of demand for materials can not be made.
Planning of the means of transportation will improve efficiency of utilization of the vessels, especially when operators share the means of transportation.
An inventory control system is an aid to appraise long term demand for material flows. These forecasts can be used to optimize the fleetcomposition.
To decrease overcapacity of the supply vesse1s fleet optimization techniques can be used.
These tools will be described in the following sections. The relations between the tools are visualized in figure 1.

ROUTING PROBLEMS
A routing problem can be characterized by:one or more depotsone or more customersa certain demandmeans of transportation with a limited capacitydelivery periods
Thence offshore transportation can be considered as a routing problem.

TRANSPORTATION OF MEN
Transportation of men and transportation of goods to offshore platforms. in the North Sea is almost not related ([6]). Transportation of .men is realized by helicopters and goods are transported using supply vessels.
Transportation of men is less complex than transportation of goods, because just one type of goods (i .e. passengers) is transported