UK: Guidance on COLREG application for dynamically positioned vessels in dive support mode and vicinity operations

UK Maritime and Coastguard Agency has issued a Marine Guidance Note - MGN 696 (M+F) offering guidance on applying COLREG rules for dynamically positioned (DP) vessels in dive support mode and nearby vessels.

This MGN was published on 21 March 2024.

1. Introduction:

• DP vessels have special limitations due to their work and are considered "Restricted in her ability to manoeuvre." ​
• These vessels often operate close to fixed assets and even small movements can cause injury or damage. ​
• Masters and Officers of DP vessels are recommended to read this notice in conjunction with MGN 424 for safety responsibilities. ​

2. Application of COLREG – In any condition of visibility: ​

• DP vessels must maintain a proper lookout and comply with the requirements of COLREG. ​
• Bridge visibility may be reduced, and a risk assessment should be carried out prior to operations. ​
• Radar equipment should be used for early warning of collision risks. ​

3. Application of COLREG – In sight of one another: ​​

• Vessels must keep out of the way of a vessel restricted in her ability to manoeuvre. ​​
• Mariners should give a wide berth to vessels displaying the required signals. ​
• Vessels should reduce speed if unable to maintain a 0.5nm Closest Point of Approach (CPA). ​
• Consideration should be given to vessel speed when overtaking a DP vessel. ​

4. Application of COLREG – Restricted Visibility: ​​

• Vessels restricted in their ability to manoeuvre must take avoiding action during periods of restricted visibility. ​
• DP vessels should have clear procedures in place for subsea operations during restricted visibility. ​
• IMCA guidelines provide further guidance on operating in restricted visibility. ​

5. Application of COLREG – Light, Day and Sound Signals: ​​

• DP vessels engaged in diving or subsea operations must display day signals and additional navigational lights during restricted visibility. ​
• Passing vessels should have due regard for the side with obstructions. ​
• Signals prescribed by COLREG should be sounded. ​

6. Operations within a 500m Safety Zone: ​​

• Offshore installations maintain a 500m safety zone, and entering without permission is an offense. ​
• Duty holders must have a collision risk management system in place. ​
• DP vessels within the safety zone are responsible for taking avoiding action. ​

7. Navigational Warnings:

• DP vessels should broadcast navigation warnings before commencing operations. ​
• Relevant coast stations and managed traffic areas should be informed. ​
• Further guidance on issuing navigational warnings can be found on the gov.uk website. ​

8. Additional Considerations:

• DP vessels should amend their AIS to indicate restricted maneuverability. ​
• Decision support tools should include COLREG compliance requirements. ​
• Familiarization and training should include COLREG compliance. ​

All regulations can be found at legislation.gov.uk

For more information, please see the document below (available only to subscribers):

Navigation Safety: Dynamically Positioned Vessels Undertaking Diving or Other Subsea Operations