The Seesaw Searchlight at Fort Fort Victoria is built just outside the West end of the Fort. The concrete position was built in 1888 by the Royal Engineers in order to illuminate the submarine minefield in the Solent. The site survives intact, although the electric light and metal arms have long gone.
For more information of the protection of defence electric lights see the linked page. The design of this seesaw emplacement is almost identical to the one built on the Lower Chatham Lines by the Royal Engineers for experimental purposes.
This short YouTube video shows the remains of one of the Defence Electric Lights outside Fort Victoria.
The image showing the seesaw searchlight is generate from AI based on an on site image that originated from the Royal Engineers Museum in Chatham,