Saw this on the UK Talking Pictures channel, who are showing all 4 series of Maigret, originally early 60s BBC. We're in the 4th series now, and the quality has generally improved, though this one has some issues!
Maigret's old friend calls him in re the murder of the captain of a fishing trawler, which has been at sea for a month, and the captain gets bumped off as soon as it returns. They're seeking the ship's young wireless officer, seen near the murder incident and has run away.
Maigret takes the chance to placate his wife in taking her for a weekend away, as her holidays are usually ruined by crime, but when Lucas turns up (even wearing a holiday hat) she realises the deception. However, she has met the girlfriend of the chief suspect, and campaigns for his innocence.
Maigret and Lucas find the young man, and try to discover what happened, but the crew aren't talking, and the young suspect seems quite confused. They realise the crew are likely innocent, if they had wanted the captain dead, he'd have had an 'accident' at sea, not wait until the ship docked. A complication is discovered, the captain had a female guest in his cabin, and they find her jealous boyfriend. They also hear that the cabin boy, on his first trip, was lost overboard, and the captain overnight had become a changed man.
Gradually our heroes home in on a suspect, and they manage to get the accused 'sparks' to tell the truth. Though the story of this episode isn't bad, some of the acting is, real amateur dramatics dodgy audition stuff. Usually by series 4 it's much better.
The 2 reviews at this time both have an odd comment, Fisher refers to the busty barmaid (the one who'd gone for a 'cruise' with the captain) as having an 'Irish' accent doubling for 'Breton' (where the port is supposed to be). She actually sounded like she was imitating an American accent heard in films.
And Prismark is again wide of the mark (happens quite often) in saying that no culprit was found, the last few minutes referred to how the cabin boy had died, how the captain got murdered when the ship docked, AND what happened to the killer. Maybe he popped out at the wrong time and missed the crucial bits?!!