Plt Off John Bisdee diary 13th July 1940 13 July 2015 By The Air Ministry in John Bisdee's Battle of Britain 13 July No entry - the Air Staff Operational Summary records: During the day the enemy focussed his attention primarily on shipping and many bombs were dropped on convoys but no hits were reported. Major fighter engagements were as follows:- i. Off PORTLAND at 1430 hours. ii. In the DOVER area at 1730 hours. iii. About 15 m. off CALAIS at 1800 hours.