The Musée Maritime is not a building but a collection of historic ships moored on the Bassin des Chalutiers, the inner basin south of the Vieux Port. The flagship is the France I, a 1958 weather-station ship that lived for years on station in the North Atlantic. Around it are a 1950s trawler, a tug, a sailing yacht, and several smaller working boats. You can go aboard most of them.
This is a hands-on museum: tight engine rooms, cramped cabins, smell of salt and oil. Kids love it. The route through takes about two hours and ends in a small exhibition hall on the quay covering the modern shipbuilding history of the town. The whole complex is a five-minute walk from the centre.