Locking operations, entrance information, stopgates, tide heights
Contact us for locking operations
In person
The Deputy Harbour Master can meet you during the tidal watch to explain the workings of the Cumberland Basin and discuss passage plans for arriving and departing Bristol Harbour. They are at the Watch House on the south side of the Entrance Lock.
By phone
Call 0117 927 3633 to speak to the Deputy Harbour Master. If you call outside of tidal watches, you can leave a message.
It's useful to tell us:
- your arrival date and time
- your name and your phone number
- the name of your vessel
- the dimensions of your vessel, including the air draft
- whether you'll be using VHF communications or a mobile phone
VHF radio
During tidal watch, you can communicate with the Deputy Harbour Master from the River Avon upstream of ‘Black Rock' lights.
Use low power only to call ‘City Docks Radio' on Channel 14
Entrance information for Cumberland Basin
From the mouth of the River Avon, the Cumberland Basin entrance to Bristol's Floating Harbour is 10.5km upriver.
The entrance lock is on the port side, approximately 0.7km past Clifton Suspension Bridge.
Cumberland Basin is the seaward approach to the Floating Harbour. It passes through the Entrance Lock, Cumberland Basin itself and the Junction Lock.
There are two swing bridges past the Entrance Lock; Plimsoll Bridge and Junction Bridge.
Vessel size
The maximum size of vessel that can be accepted, is determined by conditions in the river and the dredged depth in the harbour.
The limiting dimensions for pre-approved transit of the River Avon are:
- Length: 66 metres LOA
- Beam: 14.5 metres
- Draught: 4.50 metreb
- Masthead Height: 27.5 metres (M5 bridge charted height at HAT)
You'll need a pilot if your vessel is:
- 50 metres or more in length
- 40 metres or more between the perpendiculars
Pilotage directions
Find out if you'll need pilotage to come into the harbour.
Stopgates and tide heights
Cumberland Basin becomes tidal when the level of water in the river is above the level in the Floating Harbour.
When this happens, stopgates are closed in Junction Lock to prevent the level of water in the Floating Harbour from rising and Junction Lock is closed to navigation.
The Entrance Lock gates are then fully open to the river. This is known locally as ‘stopgate tides' or ‘on a level'.
Tides of 9.6 metres and over are ‘stopgate' tides. Tides of 8.8 metres to 9.6 metres may become ‘stopgate' tides if the level of tide is higher than predicted, or if the level of water in the Floating Harbour is below normal level.
Heights of tide relate to the Outer Cill of the Cumberland Basin Entrance Lock (deduct 3.1 metres from the heights given in Arrowsmiths Bristol Channel Tide Table under the heading ‘Avonmouth King Road')
Contact us about stopgates
If you want to enter the harbour during this period, phone the Watch House on 0117 927 3633.
They can give you up to date advice and information on when the stopgates will be closed and when you can access the Floating Harbour.
Arriving ‘on the level' and ‘stopgate' tides
On tides of 9.6 metres and over, the Entrance Lock can be navigated ‘on the level'. This means there is no requirement to lock through as the gates are open to the river and the lock and basin become tidal.
A level happens anytime between 1 hour 10 mins to 20 mins before high water, and 20 mins after high water depending on the height of tide and the prevailing conditions.
You should aim to arrive on the first inward locking to proceed through into the harbour or wait for a ‘level. You won't need to lock through, but you may have a short wait in the basin to allow stopgates to come off and access to the harbour.
Locking operations
During British Summer Time (BST), the Deputy Harbour Master will provide locking services from 3 hours before high water, between 7am and 10pm.
If you need locking services outside of these times, you'll need to give us a minimum of 24 hours' notice.
48 hours notice is required during Greenwich Mean Time (GMT) for all locking operations.
Road traffic has priority on both swing bridges during rush hour. Navigation can be affected by stopgate closures and bridge embargoes.
Times of inbound locking operations
The following times are approximate and are at the discretion of the duty Deputy Harbour Master. Contact us in advance whenever possible for further information.
- First lock: 2 hours 35 minutes before high water
- Second lock: 1 hour 25 minutes before high water
- Third lock: 15 minutes before high water
This schedule operates when there is sufficient demand and providing it does not conflict with the requirements of other classes of vessel. The times are subject to alteration by the Deputy Harbour Master.
Swing bridges
The Cumberland Basin Bridges are not swung Mondays to Fridays (except public holidays ) between 8am to 9am and 5pm to 6pm.
30 minutes either side of these times, road traffic has priority on all bridges and there may be shadow periods at the discretion of the Marine Services Supervisor.
The air draft clearance beneath the bridges to enter the harbour are:
Junction Lock Bridge, 2.5m above harbour level
Plimsoll Bridge 5.8m above harbour level (you'll need to give us 48 hours' notice to swing this bridge)
Arrival procedure
If you plan to arrive at Bristol Harbour, you must give:
- 24 hours' notice during BST
- 48 hours' notice during GMT
All vessels over 5.8 metres air draft must give 48 hours notice during BST and GMT.
When you approach the entrance to the River Avon, leave Avonmouth South Pier lighthouse close to your port side.
At 3 hours to high water, the tidal flow crossing the entrance can reach 4 to 6 knots.
Keep the Swash Bank transit lights in line until the St George's transit lights are in line. Leave the Hoveringham buoy to starboard.
Don't enter the river without sufficient depth of water available for your vessel.
For larger sailing vessels, consideration should also be given to sufficient air draft clearance for passing under the M5 Motorway Bridge.
When you approach and transition the River Avon inbound, keep a listening watch on VHF Channel 12. Inbound vessels over 30 metres or carrying more than 12 passengers must report to ‘Bristol VTS' when passing Shirehampton and Sea Mills reporting points.
If you are using VHF, contact the Deputy Harbour Master on Channel 14 ‘CITY DOCKS RADIO' at Cumberland Basin when you have passed the ‘Black Rock' lights and again when you reach the Hotwells Pontoon for docking instructions.
If the red light is exhibited on the docking signal mast at Hotwells Pontoon, contact the Deputy Harbour Master on VHF Channel 14 Low Power.
Failing this, proceed along the starboard side of the river outside the main channel to the knuckle ladder at the Tongue Head, just upstream of the lock gates. Secure alongside this ladder and establish contact with the Deputy Harbour Master for docking instructions.
When you're in the lock, keep to the outer end, where the water will be less turbulent when the lock is being filled.
Vessels will generally be asked to come alongside in the lock starboard side too.
Have fenders set and both a bow and stern line of approx 15 metres ready to be deployed.
Docking staff will lower a heaving line down to your vessel on entry.
Attach your vessel's lines to each of the heaving lines and then allow the docking staff to pull the lines up to the quayside.
Docking staff will pass your mooring lines through rings on the quayside and then back down to your vessel. Make sure your lines are tended continuously whilst the lock is being filled. You must comply with all instructions given by docking staff.
If you need a Junction Bridge swing or you're arriving on a stopgate tide, and have been directed to wait in the Cumberland Basin, you must not leave your vessel unattended without the Deputy Harbour Master's permission.