Doctor in the House S06E02 - Oh I Do Like to Be Beside the Seasick

Having put to sea, Duncan discovers that he is prone to sea-sickness so Dick gives him a healthy dose of remedial medicine. Unfortunately he overdoes the dosage and Duncan falls into the ship's swimming pool, arriving soaking wet at the captain's cocktail party. The captain sacks him and in revenge Duncan tells American passenger Mrs. Tranmere that Loftus loves to sing, so she asks him. Ultimately Loftus reinstates Duncan because the party was a huge success, due to his singing.