Listed Building: BREAKWATER FORT (382002)

PORTLAND SY67SE PORTLAND HARBOUR, H.M. Naval Base 969-1/1/158 Breakwater Fort 21/09/78 GV II Breakwater fort. c1860, but considerably modified and extended in 1884, 1900, 1912 and later. Portland stone, concrete, armour-plate steel. Locally known as "Palmerston's Folly", this was one of 4 coastal defence forts provided, others being at Plymouth and Spithead. Later armaments added in both World Wars.A small jetty running to the SW is formed over 3 segmental arches with quoins and keystones, approached by a slow- rising long staircase/ramp, left, and a steeper flight of stairs to the right; extends also to left, including unroofed 3-bay stone structure. Main fort includes 35m diameter iron core with foundations c 9m below sea level; a ring of masonry capped with concrete on granite sub-structure c 7m above sea level. The iron structure has 2 rings of iron box girders fanning from central well, forming a floor and a roof level; concave fluted underside sloping to gunports, supported by pillars between casemate ports. Walls are three thicknesses of 15cm plate backed by armour bars; roof also of concrete-capped iron. 14 guns installed 1874-75. In 1884 a steam engine was added to supply ammunition and operate the guns. Upper level altered by installation in 1900 of 2 heavy gun emplacements, and later by substitution of an armoured gun tower for the original lantern. Central well is octagonal faced with ashlar and with Roach stone rustication to each arched entry; spiral cast-iron staircase to upper level. Listing NGR: SY7077376223

Record last edited

Nov 20 2023 12:34PM