National Maritime Charity Calls On Volunteers to Visit its ex-WW2 Sea Mines   May 2015 Seventy years after they were used in the defence of Britain’s coast and harbours a national maritime charity is on the lookout for budding adventurers to visit its red sea mines which are now used as charity collection boxes. The Shipwrecked Mariners’ Society is calling on volunteers to circumnavigate the UK to complete a mine to mine challenge, by visiting all fifty mines situated around…