Black Sluice Navigation: locks and facilities

Information for boaters on the Black Sluice Navigation.

The Black Sluice Navigation is on the South Forty Foot Drain, an artificial drainage river in Lincolnshire. Unused for nearly 40 years, it re-opened in 2009. It’s a typical Fen drain, providing 31km (19 miles) of navigation into the west of Boston in Lincolnshire.

You need a licence to use the Black Sluice navigation. You can get a 1 day and a 7 day visitor licence.

Call the Environment Agency on 0370 850 6506 (see call charges) to get a licence and a navigation key to use their moorings.

Visit the Inland Waterways Association website to see the Fens Waterways map and about the Waterways Link project.

Read the recreational byelaws for Anglian waterways.

Black Sluice lock

To enter the Black Sluice Navigation you need to pass through the Black Sluice Lock. The lock connects the Black Sluice Navigation with the tidal Boston Haven.

Black Sluice Lock dimensions

  • length: 21 metres (70 feet)
  • width: 6 metres (20 feet)
  • draft: normal water depth in the lock is 2.80 metres (9 feet), however this may vary on certain tides
  • airdraft: headroom in the lock isn’t restricted

Black Sluice Lock isn’t permanently staffed. You need to book a minimum of 24 hours in advance before you want to use the lock. Please call the Black Sluice booking line on 0165 263 5219 or 0370 850 6506 to book (open Monday to Friday, 8am to 6pm).

Lock keepers can book passage through both the Grand Sluice Lock and the Black Sluice Lock.

Please note that that your booking doesn’t always guarantee passage through the lock at the time arranged. Occasionally bookings will have to be postponed or cancelled. This could be due to:

  • the Port of Boston needing to use the water in front of the lock to turn large seagoing boats
  • flooding incidents: The Black Sluice Lock can be used to discharge flood water from the South Forty Foot Drain; at this time the lock will not be available for use - red warning flags will be flying at the lock

The Environment Agency will try to give as much warning as possible if these situations occur.

Contact numbers

  • Black Sluice Lock booking line: 0165 263 5219 or 0370 850 6506
  • Grand Sluice Lock 0771 201 0920 or 0120 536 4864
  • Port of Boston 0120 536 5571

Black Sluice lock facilities

The old lock keepers cottages are now a café. The cottages have showers and toilets which are available to boaters 24 hours a day. You can get a key from the lock keeper, with a deposit.

Above Donnington Bridge, access is only possible for small unpowered boats, such as canoes and kayaks. This is due to limited water depth, headroom and width above this point, and environmental and wildlife considerations.

Black Sluice Navigation bridge height

When passing from Black Sluice Lock into the Black Sluice you pass under London Road Bridge. There is a height restriction on this arched bridge, details in London Road Bridge profile. Headroom varies from around 1.7m to 3.4m.

There are some low headroom bridges along the Black Sluice Navigation. On average, at normal summer levels there is about 3m of headroom at these bridges. There are inverted gauge boards at the lower sites, which show how much headroom is available. It’s the skipper’s responsibility to check that there is enough headroom before passing under the bridge.

Contact the local river inspector on 0165 263 5219 or 0370 850 6506 if you need any more information.

Boston Haven

The section of river between Grand Sluice Lock and Black Sluice Lock is tidal and subject to strong tidal ebbs and flows. Navigating this section of river should be undertaken with extreme caution as much larger craft will also be using this section of water. Tune in to channel 74 on your VHF radio to monitor boat traffic when navigating the Haven.


There are no permanent moorings on the Black Sluice Navigation.

Mooring is restricted to a maximum of 48 hours at Boston, Swineshead Bridge and Hubbert’s Bridge.

Published 31 March 2014
Last updated 29 August 2023 + show all updates
  1. Updated contact telephone numbers for Black Sluice Lock and the Environment Agency.

  2. First published.