IN the past year H.M. Coastguard has taken part in about 750 incidents round the coasts of Great Britain and Northern Ireland. Some were dangerous and spectacular, others were minor cliff rescues. They ranged from the recovery of a St. Bernard dog, stranded on a Cornish beach, to the rescue of four people by breeches buoy from a grounded Dutch dredger at Tynemouth in the teeth of a gale..