The first file consists of correspondence between the Engineer to the Humber Conservancy Board (Arthur Ernest Butterfield), the Chief Engineer’s Office for Northern Command (based at York), the Royal Engineer’s Office (based at Darlington), Paull Point Battery at Hull, employees of the Lighthouse Works (Smethwick), and representatives of the War Office. The correspondence is connected with construction and survey work in the vicinity of the Bull and Haile Sand forts. This includes discussion connected with lighting and the use of fog bells at Bull Fort. It also includes discussion surrounding proposals for the installation of a new jetty at the Bull Sand Fort; the previous jetty had been swept away.

Lists detailing (practice) bombs dropped to the south east of the Bull Lightship; and explosions heard at Spurn Point, Hull Fort, and Tetney Fort, can also be found in the file.

The second file comprises correspondence between the engineer to the Humber Conservancy Board, the Command Quantity Surveyor, Northern Command, York, the Ministry of Transport, London, the Navy Works Department, Liverpool, and the War Department Land Agent, Surrey, regarding the removal of the old boom defence barrier works at the Haile Sand and Bull Sand Forts at the Mouth of the River Humber. Also includes correspondence regarding proposals to install automatic light and fog bell equipment on the forts, as well as correspondence with the Hydrographic Department Admiralty, dated 16 September 1919, and later correspondence regarding the proposed sale of both forts, as well as drawings of the forts, plus an early Secret Fleet Chart showing the position of Bull Fort within the River Humber, and a further drawing of Bull Sand, dated 1919.