A close view of the aft end of the forward poppet on the starboard side of the Royal Navy battleship Thunderer (1911) on the building berth at the Thames Iron Works shipyard at Blackwall, London. The photographer has rested his camera on the starboard way alongside the poppet and is looking aft. A boy scout is sitting with his back to the camera in the foreground and a small group of shipyard officers are standing on the way checking the aft end of the poppet.