Stack Rock Fort

Stack Rock Fort is a fort built on a small island in the Milford Haven Waterway, Pembrokeshire, Wales. A 3-gun fort was built between 1850 and 1852, and then upgraded from 1859 to 1871 with a new building that completely encased the original gun tower. It is now a Grade II* listed building and a scheduled monument (registered SAM number PE334).

In 1539, the first proposal for a fortification at Stack Rock to protect the estuary was submitted by Thomas Cromwell, however his proposal was not approved. Similar proposals were made in 1748 when Lewis Morris carried out a survey of Milford Haven, reporting on shipwrecks and navigation and recommending that a small fort be built here. Another survey followed in 1817.

For over 200 years, proposals and surveys were discussed regarding the need for a fortress on Stack Rock Island, yet nothing had been done. In 1850, with the rise of Napoleon III in France, and with the new French emperor's occasionally bellicose threats towards Britain, the time had finally come to put the plans to build a fort into action. The Royal Dockyard at Pembroke Dock was finally going to have its own fort to defend it from the sea. The initial result was a tower mounting three guns, similar to the two towers in Pembroke Dock. The initial tower was elliptical in section, with a maximum diameter of 55 feet (17 m) and a maximum height of 30 feet (9.1 m). Construction commenced in 1850, being completed in 1852.

In 1858, the first appearance of the new French ironclad Gloire with its new invulnerability to the initial fort's guns rendered the initial tower and its guns as obsolete, so it was decided to completely surround the initial tower with a newly expanded and updated battery. The original design of the newly expanded fort was for two decks each of 19 casemates and 16 open air guns above, 54 guns in total, and built mainly of limestone. However, after the foundations had been started in 1861, the design for the expansion was amended to have stronger granite piers supporting iron gun shields. The expansion's new basements and magazines were completed in 1863. Then the design was altered again, for 16 large guns on a single floor of casemates in the front and seven smaller guns on two floors in the gorge or the fortification's "weak-point," in the rear of the fort facing into the Haven.

Text adapted from “Stack Rock Fort” on Wikipedia, CC BY-SA 4.0.

Stack Rock Fort ranks #3,978 of 7,044 worldwide in the atlas's castle fame ranking, and #78 of the 99 mapped in Wales. See how Wales compares in the castle statistics.

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