Scale: 1:6. A sectional model depicting a collapsible skylight for HMS 'Nimrod' (1856), a single screw gun vessel. The model is largely made in wood and is fully working to show how a skylight on deck can be folded down and covered with a hinged hatch cover preventing damage and obstruction on a flush decked vessel.

The model largely shows a recessed hatch within a portion of deck supported by three deck beams and two carlings below. By removing the hinged hatch cover and frame work underneath the four glazed panels of the skylight can be raised by large brass hinges, all of which are held in place by brass catches and rods connected to the hinged hatch cover. Each panel comprises of two sliding sash windows which comprise of three panes of glass and slide horizontally. The exterior of the sash windows are complete with metal bars for protection against damage when on deck or by foul weather.

There are various paper labels applied to the model, in particular the two largest have several sentences hand written in ink. One reads "Sheerness yard 15th May 1862. D.S.2403/62. Rec.d 11 Feb.r 1863. A proposed plan for making all the skylights on board flush deck vessels, in the neighbourhood of the capstan and chain messengers, and when it would be desirable in bad weather to instantly transpose a skylight with a cap scuttle and thus to dispense with deadlights." The other label appears to read “Explanation of model. Remove the top of the skylight and it comes fitted with knees and floor across the sides and the hatchway and lastly fid the top of the skylight over the hatchway as a cap scuttle. This plan was adopted in the Nimrod and other vessels in 1856, and subsequently in the Cormorant, the Race Horse and the Star with perfect success. The detail of this plan has been carried out by Mr Davison and Mr Bridge, the Foreman and Inspector of Joiners.”

There is a smaller paper label at the end of the midship planking, which is hand written in ink and reads “Scale. 2. inch a foot”. There is also a loose part of hatch combing made in mahogany complete with brass catches and rods. The use of this part is unknown.