During the 19th century, the naval dockyards underwent a transformation as the fleet of sailing ships was replaced by motorised vessels. The sites were industrialised and gradually specialised. In 1865, the naval dockyards in Brest became exclusively military, with the closure of the Penfeld port to commercial vessels. In 1898, after specialising in the building of vessels with propellers rather than sails, the shipyards in Cherbourg were tasked exclusively with the construction of submarines. Finally, in 1927, a decree definitively laid out the missions of the various naval dockyards: Brest and Lorient were tasked with the construction of large vessels, Cherbourg with building submarines, while Toulon, Bizerte and Saigon took charge of the maintenance of the fleet.