Listed Building record MWX1380 - Breakwater Fort or Chequered Fort, Outer Breakwater, Portland

Post medieval coastal fort constructed between 1868 and 1875. The fort was also reused in both the First and Second World Wars. Structures associated with this coastal artillery battery are visible on aerial photographs of the northern end of Portland's Outer Breakwater.

Coast artillery battery. One of four Victorian Iron Forts, the other three being the Breakwater Fort, Plymouth and two in Spithead Roads - No Man's Land Fort and Horse Sand Fort. Designed for 14 x 12.5in RML guns (38 tons). Only five were installed. These were removed by 1908 and can be seen still on the waterline by the fort. The fort was used in both WW1 and WW2. 2 x 6in Mk III guns (1918).

[Dorset Sculpture Trust seek finds from Millennium Fund to turn site into an arts centre - 1995].19th century fort in good condition. [information from 1963 aerial photographs].Breakwater Fort (Chequered Fort), on Outer Breakwater, Portland.

Blackwater Fort. A coast artillery battery constructed between 1868 and 1875 as part of Portland Harbour defences. One of four Victorian Iron Forts, the other three being the Breakwater Fort, Plymouth and two in Spithead Roads - No Man's Land Fort and Horse Sand Fort.

The fort is circular in plan and was designed for 14 x 12.5-inch Rifle muzzel-loading (RML) guns (38 tons). By 1902 it was armed with four 12-inch RML guns and four 12-pounder quick-firing (QF) guns. The 12-inch guns were removed by 1908 and can still be seen on the waterline by the fort. The fort also had its own harbour and ancillary barrack buildings.

The fort was used in both WW1 and WW2. During the First World War it was armed with two six-inch breech-loading (BL) Mk. VII gins in addition to the 12-pounder guns. Coast artillery searchlights were also added. In 1940-41 the fort was recommissioned and operated as an examination battery. It was reduced to care and maintenance by 1945 until it was abandoned in 1956. The structure is a Grade II listed building. <1-3>

Sea fort, part of Portland harbour defences. Originally intended as a casemented granite work following the 1859 Commission Report on the Defence of England, it was eventually constructed as an iron fort astride a granite base. Fourteen 12.5" guns were installed in 1874-5, and further guns were added in 1900 and 1912. <4>

Blackwater Fort located at SY 708 762. The fort was constructed between 1868-1875 by recommendation of the Royal Commission. It was a circular casemated fort armed with rifle muzzle-loading (RML) weapons. By 1902 it was armed with four 12.5-inch RML guns and four 12-pounder quick-firing (QF) guns. The 12.5-inch guns were removed after the Owen review of 1905. During the First World War it was armed with two 6-inch breech-loading (BL) Mk. VII guns and the 12-pounder guns and coast artillery searchlights (CASL) were built at the fort. During the Second World War it operated as an examination battery and was manned by 104 Battery of 522 Coast Regiment. It was reduced to care and maintenance by February 1945.

No. 1 gun emplacement was located at SY 7075 7615 and No. 2 gun at SY 7075 7625. No. 1 CASL was positioned at SY 7070 7593 and No. 2 CASL at SY 7071 7601. The rangefinder was located at SY 7075 7615. <5-6>

The 19th century fort survives in good condition. <7>

Construction work on the fort start in 1868 and completed in 1875. The guns were added in 1892. The fort is circular in plan and was designed by Captain E. H. Steward of the Royal Engineers and is constructed on a 200ft diameter ring of stone laid on the seabed. The main floor comprises gun rooms and ports of 14 heavy guns. The roof was originally designed to support two iron turrets for two guns each, but these were not installed. Below the gun floor are the shell and cartridge stores and engine rooms. The fort has its own harbour and ancillary barrack buildings. In 1892 seven 12.5 inch Rifled Muzzles Loading cannons were installed. These were replaced in 1907 by two 6 inch breech loading guns and two 12 pounder quick firing guns. The fort was abandoned in 1956. <8>

Structures associated with this coastal artillery battery are visible on aerial photographs of the northern end of Portland's Outer Breakwater <8-10>. These features were digitally plotted during the South West Rapid Coastal Zone Assessment Survey (Dorset). They are still visible at this location on the most recent comprehensive aerial images available to the project.

<1> Council for British Archaeology, 1995, Defence of Britain Project, S0011293 (Digital archive). SWX5.

<2> Council for British Archaeology, 2003, Defence of Britain Project Database, S0011293 (Machine readable data file). SDO128.

<3> Council for British Archaeology, 2006, Defence of Britain Project Archive DEB01, S0011293 (Excavation archive). SDO17227.

<4> Hogg, I V, 1974, Coastal Defences of England and Wales, 230-231 (Monograph). SWX2166.

<5> Dobinson, C S, 2000, Twentieth century fortifications in England. Volume 6.1. Coast Artillery, 1900-1956, 176-181 (Monograph). SDO17228.

<6> Dobinson, C S, 2000, Twentieth century fortifications in England. Volume 6.2. Coast artillery, 1900-1956, 271 (Monograph). SDO17229.

<7> Anderton, M J, 2000, Twentieth century military recording project: World War Two Coastal Batteries, 70 (Unpublished document). SDO17230.

<8> http://www.cyberport.co.uk/historyfile/portland_and_weymouth/dorsets_coastal_defences/breakwater_fort.htm, [Accessed 8-AUG-2006] (Digital archive). SDO20308.

<9> Royal Air Force, 17-APR-1951, RAF 540/457 F20 4093 (Aerial Photograph). SDO13116.

<10> National Monuments Record, 25-JUL-1996, NMR SY7076/10 (15552/12) (Aerial Photograph). SDO13117.

<11> XX-XXX-2009, Google Earth (Aerial Photograph). SDO12705.

<12> National Record of the Historic Environment, 1164872 (Digital archive). SDO14739.

Record last edited

Nov 20 2023 12:39PM