Development of a Decision Support System in Ship-To-Ship Lightering

Abstract

This paper focusses on the development of a tool for decision-making, tailored for personnel involved in complex Ship-To-Ship (STS) operations, to enhance the efficiency and safety of these operations. A step-wise approach has been selected. The first step includes specification, development and testing of the tool in a simulated work environment using full-mission simulators. In the second step the findings from application of the tool in the simulated work environment will be used to develop a prototype which will be tested during real life STS operations. This paper describes work done in the first of these two steps. During four iterations, a Graphical User Interface (GUI) has been made following Interaction Design (IxD) principles. The designs have been iteratively developed and tested by experienced ship's officers in a ship-handling simulator to clarify key information to enhance their Situation Awareness (SA) and decision-making process. In order to find indicators for performance, an initial performance test was carried out in a ship-handling simulator. The test indicates that a logic based Decision-Support System (DSS) can improve existing simulator-based training activities in STS operations. A Ship-to-Ship (STS) lightering operation typically involves two tankers manoeuvring in close proximity, at speeds in the range of 4-6 knots, in order to position alongside and commence cargo transfer. The operation often takes place out on the open sea, while the two ships are underway and sailing, as can be seen in Figure 1. One ship maintains speed and course, while the other ship slowly manoeuvres alongside. In an STS lightering operation the approach phase is critical in order to avoid steel-to-steel contact.

Approach Manoeuvre During Emergency Ship-to-Ship Transfer Operation with Oil Spill

“…For this purpose basically a collision avoidance manoeuvre has to be carried out in order to obtain the required safety distance between two ships and to take side by side position. The manoeuvring operations are individually different depending on variation in the environment condition, manoeuvring performance of the individual ship (Pedersen et al 2008, Husjord &Pedersen 2009, Husjord 2016. During emergency STS transfer operation can appear additional important aspects like ship and cargo condition (transhipment from undamaged side), time limits (to ensure fast transhipment) as well as water area constraints (close to port area), avoidance moving oil spill or other rescue units.…”