(IDEX Online) - De Beers' new diamond recovery vessel, the largest of its kind in the world, has set sail from a shipyard in Romania to be fitted with mission equipment for work off the Namibian coast.The $470m ship will use sub-sea crawling extraction techniques to retrieve marine diamonds from the seabed, which will then be processed on board.It was commissioned by Debmarine Namibia, a 50/50 joint venture by De Beers and the government of Namibia.The 177-meter ship, known as Additional Mining Vessel 3 (AMV3) will join Debmarine's existing five-strong fleet, which dredge thousands of tonnes of sediment from 150 meters below the seabed, 12 miles off Namibia's south-western coast.AMV3 is expected to increase Debmarine's output by about 500 000 carats.It set sail from Damen Shipyards, Romania, last month and is expected to reach the Port of Cape Town, South Africa, in the next few days.Debmarine produces 1.4m carats annually. It uses either airlift-drill technology, or on more modern ships, a 280 tonne track-mounted remote-controled crawler to bring up the gravel. Then they wash, sift and sort it on board, and return the sediment - as well as the odd octopus - back to the bottom of the ocean.The diamonds are automatically sealed into barcoded steel briefcases and flown by helicopter three times a week to vaults back on dry land, in the capital Windhoek to be graded.Pic of AMV3 courtesy @VisualCre8 / Damen