Introduction

STS Operations are becoming more common around the world, for instance off the US coasts and northern part of Europe (including Baltic and Arctic waters).  A leading lightering company is Skaugen PetroTrans, Inc that executes some 900 STS operations a year.  Experienced Mooring Masters claim that such operations are carried out with any type and combination of tankers, all individually different because of weather conditions, sea states, manoeuvring performance etc. Mooring Masters also claim that differences in interaction between vessels are significant.Importance of knowing exactly what’s going on on board the ships is essential for conducting a safe and efficient STS operation. In the future, other types of STS operations are anticipated to take place, e.g. tandem configurations.

Objectives

The overall objective is to develop a decision-support system, based on the principles of an automatic control system, for the Mooring Master and ship navigation officers in order to enhance operational safety and efficiency. The system shall be suitable for training of STS operations on simulators as well as on board actual ships.

Milestones

•  Field observation programmes of lightering operations in order to gather knowledge on how it is carried out and the dynamics involved.
• An experimental test programme was carried out on board the research vessel 'Shioji Maru' of Tokyo University of Marine Science and Technology off the coast of Tateyama, south of Japan, during July 23rd - 25th. The test programme included 'Shioji Maru' to follow a 'ghost ship' with a lateral separation of 100 m in various headings such that different current conditions could be experienced. 'Shioji Maru' can be completely controller by an external PC with adequate software. Controller gains were adjusted in a systematic manner aiming to achieve the demanded distance in lateral separation by automatic rudder orders. These field test results will become a vital part of the ongoing development of the theoretical framework (algorithm) of proposed controller design for STS operation with application of a relative distance sensor. Results are expected to be presented on upcoming conferences.
• Testing of the decision-support system in an actual STS operation

Research Activities

Theoretical work: 

• Develop, verify and validate algorithms to generate suitable manoeuvres for STS operation.
• Develop, verify and validate a suitable decision-support system for STS operations.

Experimental work:

• Provide documentation and measurement data of STS operations to other WPs in an early stage of the project.
• Testing man-machine interfaces on simulator, training ship and on board an actual STS vessel.
• Testing of decision-support systems based on proposed algorithms.