Ministry of Defence (MOD) Shoeburyness: Range Sea Danger Area

Staying Safe Near the RSDA 2024

With the summer months just around the corner, it’s timely to remind local sailing and watersports clubs of the restrictions in the vicinity of the Foulness and Maplin Sands. QinetiQ operates the live weapons test and evaluation Range in Shoeburyness and on Foulness Island in Essex, known as MOD Shoeburyness. The Range is active Monday to Friday (occasionally at weekends), all year round, conducting activities that involve firing and detonating live ammunition, often over long distances, out to sea.

To enable the Range to work safely and ensure that hazardous activities do not present a risk to members of the public, it operates under the jurisdiction of the Artillery Ranges Byelaws 1936 and the Shoeburyness and District Military Lands Byelaws 1935 (under the Military Lands Acts 1892 to 1903). The byelaws govern the use of the land and rights of access and passage through the byelaw area. The byelaws cover an area of the Thames Estuary and the North Sea and the inner waterway that runs from Havengore Creek across to the River Roach and the River Crouch. These areas are known collectively as the Range Sea Danger Area (RSDA), unauthorised entry to the RSDA is both illegal and dangerous.

QinetiQ manages access to the RSDA ensuring that boats, yachts and personal watercraft (PWC) do not enter the area illegally, putting themselves and their vessels at risk. In order to monitor the RSDA whilst the Range is active, QinetiQ uses marine surveillance radar and has a Range Safety Boat which patrols and advises any unauthorised vessels to leave in accordance with the byelaws and in the interests of health and safety.

In recent years, there’s been an increase in vessels sailing close to the Range coastline overnight or on weekends, then becoming stranded within the RSDA, effectively leaving the vessel in an active weapons danger area when the Range resumes explosive operations. This is not only dangerous for anyone on board, but also puts the vessel at risk and can delay important Range operations. Recovery of stranded vessels can be costly and difficult with owners having to wait for the Range to authorise access, and for the right tidal conditions etc. This is one of the reasons that the Inner Sea Area is closed to all marine vessels, at all times irrespective of the status of the Range.

Skippers can find guidance on the location of the Inner and Outer Sea Areas that comprise the RSDA on the MOD Shoeburyness website where there is a section dedicated to safety information for mariners. There is also information about how to contact Range Control for advice, and the meaning of the Red Flags that are used to indicate the status of the RSDA. If you or your members sail in the vicinity of the Range, we strongly recommend that you familiarise yourself with the restrictions.

Our website also has a guide for anyone wishing to access the inner waterways via Havengore Bridge and we post status alerts on X (formerly Twitter), to notify when either Havengore Bridge or Potton Bridge is non-operational due to mechanical failure or maintenance. Follow us @SHB_Alerts or sign up to alerts for the marine community by emailing your request to

In addition to the restrictions and prohibitions imposed by the MOD byelaws, the MOD foreshore is included in the ‘Restricted Area’ of a PWC PSPO introduced by Southend-on-Sea City Council. Fixed penalties will be issued to anyone found to be in breach of the Order. Full information can be found here.

QinetiQ – Information for Mariners

MAIB Safety Bulletin: 2023
2023 SB3