There have been major advances in maritime surveillance technologies in recent years and monitoring has become an important barrier function for avoiding hazardous incidents, primarily in relation to collisions between ships or drifting objects and offshore facilities or other vessels.

The barriers for limiting the risk of collisions with ships or other objects include reducing the potential for collision-prone situations to arise. When such situations do however arise, it is important to have barriers for identifying/detecting conditions that may lead to failure, hazard and accident situations; barriers for preventing them becoming accidents; and, if the accident is unavoidable, barriers for limiting damage or loss.

Maritime surveillance is an important barrier element in the barrier for identifying/detecting vessels on a collision course. Alerting a vessel on a collision course, to ensure that it corrects its course, is a barrier element in the barrier for preventing such a situation becoming an accident.

Alerting the at-risk facility is a barrier element in the barrier for limiting damage and loss of life if the accident becomes unavoidable, by enabling the facility to take measures, such as evacuating personnel.

The focus of the study was systems and safety-critical operations relating to maritime surveillance and alerts. Ship course correction is not included in the study since this is beyond the control of the operator and/or vessel monitoring and alert system.


The participants interviewed for this study state that they generally perceive maritime surveillance to be robust, with the requisite detection capability and very little downtime.

The requirements in the regulations as well as NORSOK S-001 (Chapter 25), NORSOK T-101 (Chapter 23) and Guideline NOG-064 (Chapter 8) are seen as somewhat unclear in certain respects. Clearer definitions and descriptions of the following aspects are desirable:

• What are “abnormal conditions” in relation to a ship on a collision course?

• What is a small vessel and what is a large vessel, in terms of radar cross section? (NORSOK T-101 specifies a radar cross section of 1000 m² for larger vessels/objects, but no equivalent for small and medium-sized vessels/objects.)

• Weather and sea conditions – what do “24/7 all year in all expected weather conditions” and “24/7 all year with exception of extreme weather conditions” mean?

• What must a monitoring system include and what is required when a facility has to take care of monitoring “on its own behalf”?

• Guidelines or principles for adapting performance requirements for normally unmanned facilities, taking into account actual time requirements in the event of an evacuation.

• The status of NORSOK T-101 in relation to regulations and associated guidelines/NORSOK S-001 is somewhat uncertain.


The objective of the study was to assist in improving competence in the industry concerning risk and factors associated with maritime surveillance, and to increase robustness and thereby reduce the likelihood of failure, hazard and accident situations linked to maritime surveillance.