The file consists of correspondence between the Engineer to the Humber Conservancy Board (Arthur Ernest Butterfield) and various companies and suppliers of marine equipment and spare parts. The subject matter is the overhaul and repair of gas floats and beacons belonging to the Board. This includes manuscript reports detailing the positions and readings of buoys and floats: they provide information on the type of float, its position, test, date of test, monthly average pressure, and any general remarks. It also includes lists outlining prices quoted by various companies tendering for the overhaul work.

There is also correspondence discussing the purity of the oil required by the gas buoys; coal gas created problems when mixed into the oil used by the buoys.