Office at Port Stanley. At first, mail bags were airdropped but some fell into Argentine minefields. A method was then devised to allow the Hercules to deliver bags without having to land by trailing a grappling hook attached to the bags which snagged a wire strung between two poles. Built in the 1970s, the airfield had a runway. It was unusable because it had been cratered by the RAF. Its rehabilitation was undertaken by 11 Field Squadron and 59 Independent Commando Squadron. The Argentinians had already repaired three craters. The others were filled in and topped with Argentine aluminium matting. A huge crater caused by a bomb required over of matting. "Scabs", or scrapes in the runway surface, of which there were several hundred, were repaired with Bostik 276, a magnesium phosphate cement and aggregate mixture. There were 47 Hercules and several hundred Harrier landings before the airfield was closed for repairs on 15 August. The runway was too short for use by the RAF's Phantoms, so 50 Field Squadron (which had been detailed for the task in May) began extending it to . Some of airfield construction stores, plant and equipment were landed for this purpose. of quartz granite rock fill was used, which was obtained by 3 and 60 Field Squadrons from a local quarry. Aluminium matting was laid along the whole length of the runway. The first Hercules landed on the new runway on 28 August. Subsequently, RAF Mount Pleasant was built as a permanent airbase, and opened by Prince Andrew on 12 May 1985. Sites for the breakdown and storage of bulk supplies were limited, and the warehouses were initially used for the Argentine prisoners. While Port Stanley provided anchorages for deep draft vessels, its berths were only deep, suitable only for shallow draft vessels. The Royal Engineers built two slipways for mexeflotes and LCUs. As late as April 1983, the Ministry of Defence had 25 ships on charter to supply the Falkland Islands. About 1,000 personnel were being ferried to and from the islands each month, requiring the services of Uganda and Cunard Countess. To provide a regular service, a ferry, the SS St Edmund was taken up and commissioned as a troopship, HMS Keren, although it was decommissioned becoming MV Keren a few weeks later. The port was replaced by a £23 million floating wharf and warehouse complex that opened on 26 April 1984.