The file consists of correspondence between the Engineer to the Humber Conservancy Board (Ralph John Hindmarsh), the Assistant Superintendent for the Upper Humber (based at Brough), and various contractors and equipment suppliers. The subject matter is the operation and maintenance of the Upper, Middle, and Lower Whitton Lightships. This includes documentation of collisions with passing river traffic, and expenses incurred by the Conservancy Board as a result.

The file also includes specifications for overhaul and maintenance work required by the lightships, and for the hire of temporary replacement vessels.