– two prolonged blasts followed by one short blast to mean ‘I intend to overtake you on your starboard side’;
– two prolonged blasts followed by two short blasts to mean ‘I intend to overtake you on your port side’;
– two prolonged blasts followed by one short blast to mean ‘I intend to overtake you on your starboard side’;
– two prolonged blasts followed by two short blasts to mean ‘I intend to overtake you on your port side’;