Doctor in Trouble (1970)
Doctor in Trouble is a 1970 British comedy film, the seventh and last film in the Doctor series. It was directed by Ralph Thomas and stars Leslie Phillips as a doctor who gets accidentally trapped on an outgoing cruise ship while it begins a round the world trip. The cast was rounded out by a number of British comedy actors including James Robertson Justice, Harry Secombe and Angela Scoular. It was based on the story Doctor on Toast by Richard Gordon.
More at Wikipedia.