Scale: Unknown. A working model depicting a midship gun deck of the armoured turret ship HMS Thunderer (1872). The 25 ton muzzle loading gun is rifled, turned in wood, and painted black. The carriage itself is made in wood, steel, and brass - most of which is painted black or left in natural brass. The carriage is mounted on brass rails screwed to the wooden planked deck. There are a number of working components which control the gun in terms of elevation and arc of fire, as well as the mechanism to run the sliding carriage in and out to allow the gun to be positioned for firing and reloading. In addition to the wooden deck is a small section of hull surrounding the gun port which is cross hatched giving the impression that it is armour plated. A small card label describes the carriage as being designed or proposed by a Captain Scott. There is also a small ivory(?) label attached to the wooden deck which is inscribed "HMS Thunderer Museum Item No A7".