The UK Royal Navy has been conducting a survey of Milford Haven as part of the navy security exercise Operation Rococo.
The Royal Navy will use its Sandown Class minehunters HMS Bangor, HMS Penzance and a Hunt Class mine countermeasure vessel HMS Hurworth along with a navy diving team and portable survey equipment to gather the necessary data.
The collected data will be used to update a database that will inform the navy of any future threats and operations to clear seaways and maritime infrastructure.
Surveying the key strategic harbours, to ensure safety across UK waters for the shipping industry, had begun in 2004. The current 14-day survey began on 19 October 2009.