Marine Operations: 500m Safety Zone

April News

The latest document from the Marine Safety Forum (MSF), is aimed at providing the offshore workforce with a better understanding of the hazards involved in offshore marine operations. The MSF is primarily focused on actively promoting safety within the marine sector of the oil and gas industry. It also provides an insight into how installations and vessels can work together to ensure safer marine operations within the 500m zone. Data shows the greatest proportion of risk from collision comes from the vessels that are invited to enter the 500m zone, i.e. the ones that can and should be managed by the installation.

The document looks at Dynamic Positioning (DP) reference systems and the different type of laser and microwave targets required. The quality of the target used in laser Position Reference Systems (PRSs) will determine the strength and quality of the return signal.

Absolute Signature to provide safer positioning in the 500m zone

The Absolute Signature (AS) Prism from Guidance Marine is designed to perform and last in the harshest of marine environments. The bright coloured exterior allows vessels to easily identify the visual target from a distance. When operating on DP with local position reference sensors, a vessel requires high quality, line of sight targets mounted on the offshore installation. The AS Prism is a retro-reflector that returns the laser signal back to the sensor, it is used by the laser PRS to precisely measure the range and bearing to the AS Prism to calculate the relative position and heading. In addition the Absolute Signature Prism uses a patented technique eliminating the potentially dangerous problem of target ambiguity with the CyScan AS sensor, whilst remaining backwards compatible with all existing laser PRS.

Our customers permanently installed Rugged Prisms to:
  • Eliminate the need for an initial handover of targets 
  • Speed up vessel loading and unloading
  • Improve target acquisition and quality of feed

Key Features

  • Robust housing design suitable for handovers
  • Increased range and durability over tape targets
  • High visibility, easy to identify
  • Easy 'drop on' rail mounting 
  • Suitable for long-term wall or handrail mounting
  • 3 year warranty


Benefits of Prisms

  • Reflect a much higher percentage of light - stronger signal
  • Greater range
  • Do not suffer UV degradation
  • Easier for the DP system to separate from reflective clutter coming from the asset


Guidance Marine always recommend Rugged Prisms

Left (circled): After advice from Guidance Marine, all the Dudgeon transition pieces (TPs) manufactured by Smulders have three Rugged Prism clusters installed per TP. The Dudgeon wind farm has over 200 Rugged Prisms installed on 67 turbines.

Right: In contrast on the DanTysk wind farm in Denmark they're using two reflectors per TP . Guidance Marine always recommends Rugged Prisms.

Contact Guidance Marine to discuss how we continue to position our customers' vessels safely and cost effectively. A member of our team will be able to assist in achieving optimum sensor performance with best practice target installation.


© Copyright 2021 Guidance Marine