Tuesday 9 February 2010

Charting Gibraltar waters

(Agencies & Gibraltar Chronicle) A specialist Royal Navy vessel has spent the past month updating the nautical chart for British waters in the Bay of Gibraltar. The crew on HMS Enterprise (photo), one of the navy’s two survey vessels, has worked to map the seabed and the coastline from Camp Bay to the runway. Key parts of the chart had been updated fairly regularly, others had not been surveyed since the 1950 and existing nautical charts do not reflect recent changes such as the Ocean Village mid-harbour reclamations.>The work, commissioned by the UK Hydrographic Office, an agency of the Ministry of Defence that produces nautical charts for the Royal Navy and international mariners is being carried out in support of the Government of Gibraltar and will be used to update the navigational charts to ensure the safe passage in and out of the harbour for all vessels. Among other information, it accurately marks the depth of the water at any given point and records important navigational aids. Any mariner sailing into Gibraltar needs an accurate and reliable chart, whic is essential to ensure safety of navigation.

The vessel, under the command of Commander Adam James, is equipped with sophisticated sonar and positioning equipment able to produce detailed maps of the seabed.

In a curious coincidence, given the history of wreckage surveys in the area, the equipment on HMS Enterprise is similar to that used by US treasure hunters Odyssey Marine Exploration to search for underwater wrecks. A key element of the work was updating information on over 100 wrecks in waters close to the west side of Gibraltar. However, most of the work in Gibraltar was carried out by the HMS Enterprise’s small boat, SMB Pioneer, which carries similar kit able to collect data up to a depth of 100m.

Notable wrecks include the SS Rosslyn, a British steamer that sank in 1916 and lies in around 20m of water just off the South Mole, and the Excellent, a British Schooner that sank in 1895 and lies in 25 metres of water off the Detached Mole.

Both ships were last checked in 2006 and, because the profiles of these wrecks can change in stormy weather or heavy swells, it is vitally important for safe navigation that they are surveyed regularly.

Another important task carried out by the mixed-gender crew of HMS Enterprise was to accurately measure the position of many navigational lights that were recently replaced but have not yet been identified on the chart.

The information collected by the ship will be shared with the UK Hydrographic Office’s counterpart in Spain, which in turn provides data on the Spanish seabed.

HMS Enterprise was due to sail from Gibraltar this week but its departure was delayed after the SMB Pioneer sustained significant damage during a recent storm but a replacement vessel will arrive in the coming days and the ship will depart later this month for the Arabian Gulf , where its work will involve high-resolution charting of key waterways through which both naval and merchant vessels transit. Survey work such as this helps ensure and improve the production and flow of key commodities such oil from the Middle East.

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