In 1860 it was decide by Lord Palmerston ( he also was involved with Crownhill fort in Plymouth), he had a plan for the defence of Plymouth. The Breakwater Fort was designed to defend the entrance to Plymouth Sound with Bovisand and Picklecombe forts. It was designed by Captain Siborne, they started work in 1861 and it was completed in 1865. It was built on on Shovel Rock and is just inside the Breakwater not connected to it.
The navy put spotter huts on the breakwater, using the old huts that kept the pony’s (that used pulled the stone trucks) sheltered at night