Hydrography in the Port of Southampton

A Brief Description

The Port of Southampton maintains a permanent hydrographic survey capability. The Hydrographer and his staff are part of the marine department, based in the Vessel Traffic Services (VTS) centre, at 37 Berth (Dock Head) in the Eastern Docks. The marine department is headed by the Harbour Master.

 The primary function of the Hydrographer and his team is to

 "Continuously monitor the Bathymetry (Seabed topography) within the Port Limits, and to bring any changes to the attention of all mariners using the port, by the most appropriate means"

This is achieved by regular hydrographic survey, the results of which are published locally in the form of charts and plans. These are used by the VTS officers and Pilots to assist in bringing vessels safely into the Port. In addition, all the survey information is sent to the United Kingdom Hydrographic Office, where it is used in the compilation of British Admiralty Charts. Thus the surveys produced by the Port of Southampton are available anyone who posses an up to date Admiralty Chart covering the Port of Southampton. In addition, some information of a particularly urgent or temporary nature, may be disseminated by means of local and / or Admiralty notices to mariners.

As well as monitoring changes in water depths, the Hydrographers are also concerned with maintaining the depths advertised to port users, in the interests both of safety of navigation, and the commercial viability of the port. This is achieved by the careful monitoring of the regular surveys to identify areas of siltation. This is followed by the planning and monitoring of regular maintenance dredging, which is required in the port to ensure that safe navigable depths are available.

Closely connected with all the hydrographic survey work, is the monitoring and recording of tidal events within the port, both the rise and fall of the water, and the tidally induced currents. The Hydrographers therefore maintain 3 tide level recorders within the port, and periodically review the tidal current (rate and set) information available in local and Admiralty publications.

Charting Southampton

The Port of Southampton covers a water area of 18 square miles (46.6 km²) which is fronted by a shoreline 45 miles (72.4 km) in length, all of which is regularly surveyed as part of a rolling program. Frequency of survey depends on the nature of the area, which is broadly subdivided as follows:

Area / Typical use / Frequency

Main Deep Water Channels & berths / Critical navigation for deep drafted vessels / 6 Months

Other Dredged Channels etc. / Navigation by smaller ships / Annual

Other Areas / Used by yachts & small boats etc. / 3 years

On average, the survey of the port alone requires more than 60 charts to be produced each year. Each chart requires field survey varying from about half a day for the smaller areas to anything up to two or more weeks for the larger areas, which are plotted on a smaller scale. In addition, a large number of interim surveys are carried out each year in connection with dredging projects as well as special investigations of reported shoal areas, or specially requested surveys in connection with engineering projects or proposals.

Charts are also regularly produced from surveys on behalf of third parties. For example The Nab deep-water channel is currently surveyed on a contract basis.

The survey work is carried out by a dedicated Hydrographic survey launch, the “Protector”, or the smaller survey / patrol vessel “Sentinel”. Both “Protector” and “Sentinel” are equipped with a modern computerised sounding system, consisting of a dual frequency survey Echosounder, with digital output, and a Differential Global Positioning System (DGPS) satellite receiver, which receives accurate corrections from our own dedicated reference station.

This system is allied to a computerised survey reduction and CAD (Computer Aided Design) plotting system in the office ashore. The production of surveys from planning to final chart is therefore achieved completely within the department, allowing the highest standards of quality control.

The “Protector” and “Sentinel”, and indeed any vessel engaged in survey work, or otherwise restricted in its manoeuvrability (for example a dredger) will be easily recognised by the international visual signals (shapes), and / or Local Flag signals which will be prominently displayed. (see below).

In addition the launches can be identified by the word SURVEY in prominent lettering on each side of the wheelhouse. Other port users are always requested to give as much searoom as possible while a vessel is engaged in survey work. This is not only for the sake of safety, but also to avoid unnecessary wash, and aeration of the water by propeller action, as both of these reduce survey accuracy and may require survey lines to be sailed again.

Some Useful Hydrographic Links

The Hydrographic Society of the United Kingdom

International Federation of Hydrographic Societies

United Kingdom Hydrographic Office

International Hydrographic Organisation