Barrage locking procedure

Locking procedure

The locking procedure for the Barrage is as follows:

  1. Vessels with a draught over 2.0m should contact Barrage Control on VHF Channel 18 well in advance of arriving at the Barrage.
  2. Outbound locks will run on the hour and at half past the hour. Inbound locks will run at quarter past and quarter to the hour. For information about the current locking restrictions, please seeĀ NTM 15 Weekend Barrage Locking Restrictions.
  3. Request an inbound or outbound passage through the locks via VHF Channel 18. Communications through the Barrage Control VHF base station are recorded for operational, training and health and safety reasons.
  4. Listen on VHF Channel 18 for instructions on how to enter the lock. Observe and comply with the light signals displayed and any instructions given.
  5. Enter the lock and moor as far forward as possible on the end cleat using appropriate fenders and mooring lines. Use at least two lines, fore and aft, and turn off your engine. You may be required to raft up to another vessel, and for this reason it would be beneficial to rig lines and fenders to both sides of your boat.
  6. Once inside the Bay, mariners should maintain a listening watch on VHF Channels 16 and 18.
  7. Vessels leaving the Bay should monitor VHF Channel 16 and VHF 68 South Wales Radio, once they exit the Outer Harbour.

Safety while locking

For your own safety and that of others while locking, please abide by the following rules at all times:

  1. Listen to and follow instructions given to you by Barrage staff.
  2. Keep clear of closing/closed lock gates and moor your vessel securely in the lock. Large volumes of water are discharged or used to fill the locks, causing turbulence.
  3. Always read and follow the instructions/advice on the lock signage.
  4. In the event of an emergency, contact Barrage Control immediately on VHF Channel 18 or by calling 029 2070 0234.
  5. The lock ladders are for emergency and staff use only.
  6. Do not refuel or pump bilges whilst in the locks.
  7. Turn your engine off when in the lock.

Cardiff Harbour locks video

This video demonstrates the passage for vessels leaving Cardiff Bay and heading towards the Severn Estuary.

Lights and signals

A series of lights will be displayed at the Barrage lock entrance. The relevant lock number is shown beneath the light signal.

Do not enter


Enter on instruction from Barrage Control

Outer Harbour

The light signals above may also be displayed at the entrance to the Outer Harbour and have the same meaning for inbound traffic. In addition, the following signals may be used at the Outer Harbour entrance.

No lights: proceed with care

3 red lights flashing: emergency stop and await instructions

Vessels may not anchor in the Outer Harbour without permission from Barrage Control. On occasion, parts of the Outer Harbour may be dry at low water, so caution is advised.