Two 5.5 inch mounted in steel gun houses on the roof of the fort together with an emplacement for a Bofors AA gun. At this time there were several searchlight positions both in and immediately outside the fort. Bowater's Farm (1,200 yards WNW of Coalhouse Fort) developed as major A.A. gun site originally with 4 x 3.7 inch guns, then later 4 x 4.5 inch guns and finally 4 x 5.5 inch dual purpose guns which could be used in an A.A. role or for coast defence. These guns became part of the Rotor system and were not dismounted until the 1950s.
Manning of Coalhouse Fort guns transferred from 356 Coast Battery to a specially trained Home Guard contingent.
Acquired by Thurrock Urban District Council from the Ministry of Defence for development as a riverside amenity.
Conservation and restoration started by the Coalhouse Fort Project (Registered Charity No. 289952). This volunteer group has opened the fort to the public every year since then.