Crenellated guardhouse, 1846 model

The crenellated guardhouses of the 1846 model (corps de garde crénelés modèle 1846) were gun-batteries built along the coast of France as the result of a standardisation of coastal-defence redoubts during the reign of Louis Philippe I.

This standardisation came as an attempt to complete the defensive chain begun by Napoleon in 1811 with his model towers, left incomplete on his abdication in 1814.

[1] Along with the construction of the battleship La Gloire, they represent part of a 20-year trend of French naval and coastal re-armament, to which the United Kingdom eventually responded by building its own steam battleship (Warrior) and its own coastal defence chain (the Palmerston Forts) during the 1860s.

Square in plan, buildings of this size were slightly pyramidical in shape.

This sub-type housed 20 men and had two murder holes sticking out from either side.