The Submarine Mining Establishment at Milford Have was built on Pennar Point Field with the whole peninsular being War Department Land. The pier for the mine deployment was on the South West side with all the building concentrated on the south shoreline. This area has now been destroyed, although traces of the pier can be seen.
Authority to build the jetty and pierhead with crane and tramway, was given in 1876. Worked commenced in March 1876 and work was completed in February 1877.
The main engine room for the Submarine Minefield was built in the Chapel Bay Quick Fire Wing Battery just outside Chapel Bay Fort. The minefield was intended to be laid between Chapel Bay Fort, Stack Rock Fort and South Hook Fort.
For more information on the use of mines between 1863 and 1907 see here.