New precautions for French submarines at sea after the accident with the Pluviôse according to the Dutch magazine Marineblad dated 1910-1911 no. 7

An item reported that as result of the accident with French submarine Pluviôse new measures were made for submarine at sea. The submarines were to be escorted by a ship to warn passing steamships. Coastal stations were to show special signals and submarines were not allow to use passing ships as potential targets. The minimum diving depth was 16 metres before moving and when she came to the surface was the engine to be stopped and via underwater receiver listened for the noise of turning screws. The periscopes were to be lengthened with another 4 metres and each submarine was to be fitted out with a signal mast showing a flag. (1)

Note
1. The Q 51. Laid down at the Arsenal de Cherbourg, France on 27 May 1905, launched on 27 May 1908, commissioned on 10 May 1908, sunk due to a collision with the packet boat Pas de Calais off Calais, France on 26 May 1910, salvaged, repaired and recommissioned, stricken in 1919 and sold to be broken up in 1925.