Covered Slip (S 180)

The No.1 Covered Slip, located in Devonport Dockyard, dates back to the 1770s, with its cover designed in 1814 by Sir Robert Seppings. This structure features a timber frame with a metal sheet mansard roof, along with a slip made of limestone and granite. The design includes an apsidal aisled plan, with an open east gable formed by one of the frames. The south side is open below the roof, while the north side is against the Dockyard retaining wall. The slip has raking sides and a curved end with two steps, leading to an entrance that opens into the river.

Inside, the timber frame consists of composite stanchions that support cantilevered principal rafters extending out on each side, along with raking braces, braced horizontal collars, and two outer struts. Historically, covers for slips were introduced in naval dockyards to protect wooden ships during construction. Between 1814 and 1821, most of the dry docks and all slips at Devonport received timber-framed housings, with only two surviving today, the largest of which is at Chatham. When built, these structures had the widest span roofs in Britain and were second only to riding schools in Germany and Russia worldwide. They anticipated the iron slip covers of the 1840s and later railway sheds.