A keen-eyed captain of a West German cargo ship rescued two British fishermen who were close to death after six hours in the English Channel, Falmouth coast guard said today. ``They were just two heads bobbing in the water,'' said coast guard duty officer David Mayall. ``They were very lucky to be seen.'' With water temperature at 59 degrees, ``we would expect people to die after that length of time in the water,'' Mayall said. ``It was pure luck we spotted them,'' said Capt. Gunter Feicks of the Hamburg-registered Jan Becker, 3,170 tons, which was en route from Rotterdam to Waterford in the Irish Republic. Fishermen Fred Steel and Gregory Lett, both age 38 from Cornwall, grabbed life belts and jumped into the sea at 2 a.m. Sunday when their 60-foot boat, Semper Parates, sank from an unknown cause in 10 minutes off Land's End. Six hours later, the freighter passed by and Feicks, looking through his binoculars, spotted something in the water ``that shouldn't have been there.'' The ship called for help and a Royal Navy helicopter winched the two men from the sea and flew them to a hospital in Truro. They were suffering from hypothermia _ subnormal body temperature _ but were comfortable, the hospital said.