Editing Fort Blockhouse (section)

===Royal Navy Submarine Base (1905-1998)===
{{main|HMS Dolphin (shore establishment)}}
[[File:B10 RP 2843.jpg|thumb|right|[[HMS B10|HMS ''B10'']] setting off from Fort Blockhouse (c.1906-1912).]]
The Royal Navy was not persuaded of the benefits of submarine mining and by 1903 the [[Admiralty (United Kingdom)|Admiralty]] was lobbying the [[War Office]] to take over submarine mining bases and to replace the fixed minefields with mobile [[submarines]], in order to provide a more effective line of defence.<ref name="Lambert2001">{{cite book |last1=Lambert |first1=Nicholas |title=The Submarine Service, 1900-1918 |date=2001 |publisher=Ashgate |location=Aldershot, Hants. |pages=42–48}}</ref> Fort Blockhouse was duly turned over to the [[Royal Navy]] in 1905 to serve as a 'Submarine Boat Station': five [[Holland-class submarine]]s were moved there, together with their depot ship [[HMS Hazard (1894)|HMS ''Hazard'']], and training was provided for submariner recruits in what would become the [[Royal Navy Submarine School]]. By 1909 a pier had been built along the north-west edge of the headland, creating an enclosed pool of water; further to the west a 'petrol pier' was built for refuelling.<ref name="nhle5">{{NHLE|desc=Submarine Escape Training Tank (SETT), HMS Dolphin|num= 1414020|access-date=6 September 2024}}</ref> A [[Hulk (ship type)|hulk]], [[HMS Dolphin (1882)|HMS ''Dolphin'']], was moored nearby to provide additional accommodation and from August 1912 the name [[HMS Dolphin shore-establishment|HMS ''Dolphin'']] was extended to cover the whole establishment.<ref name="nhle1" /> From that year the [[Commodore Submarine Service]] was based there, as were his successors over the next 65 years.<ref>{{cite news |title=Fleet move for Flag Officer Submarines |url=https://issuu.com/navynews/docs/197708 |access-date=9 September 2024 |work=Navy News |date=August 1977 |page=1}}</ref> During the [[First World War]] HMS ''Dolphin'' was the navy’s principal submarine depot. From 1917 periscope training took place there; this later developed into 'Perisher': the [[Submarine Command Course]].<ref>{{cite book |last=Davidson |first=Jon |author2=Allibone, Tom  |title=Beneath Southern Seas |publisher=University of Western Australia Press |location=Crawley, WA |year=2005 |isbn=1-920694-62-5 |oclc=69242056|page=108}}</ref>

[[File:Fort Blockhouse.jpg|thumb|left|Modern buildings can be seen within and beyond the Fort, including the prominent Submarine Escape Training Tower (centre left), the Vulcan Block (centre right) and the top of the ''Upholder''-class facility (far right).]]
The period between the two world wars saw significant expansion at HMS ''Dolphin'': on the open courtyard within the bastions of the fort a number of administrative and other buildings were erected; upper floors were added to the casemated accommodation blocks, with the officers' block being extended to create a new [[officers' mess]].<ref name="nhle2" /> The establishment also expanded beyond the lines of the original fort on Blockhouse point: west of the main gatehouse, the defensive moat was infilled in the 1920s and the earthworks were levelled; 'Vulcan Block', providing accommodation for seamen, was built there in 1933, along with a new guardhouse and various other buildings.<ref name="2007PeninsulaCAA" /> East of the original fort, alongside the north bastion, a block for [[Warrant officer (United Kingdom)#Royal Navy|Warrant Officers]] was built facing the harbour; to the north-west, overlooking the piers, a headquarters block for the Rear Admiral was erected in 1937-38.<ref name="2007PeninsulaCAA" />

[[File:Gosport, Hampshire - geograph.org.uk - 4024570.jpg|thumb|right|The SETT, flanked by erstwhile buildings of the RN Submarine School.]]
The prominent [[Submarine escape training facility|Submarine Escape Training Tower]] (SETT) was built in 1953, and opened in 1954. The need for such a training facility had been made apparent by the loss of ''[[HMS Truculent (P315)|HMS Truculent]]'' in 1950.<ref name="2007PeninsulaCAA">{{cite web |title=Haslar Peninsula Conservation Area Appraisal |url=http://www.gosport.gov.uk/EasysiteWeb/getresource.axd?AssetID=2645 |website=Gosport Borough Council |accessdate=8 February 2019 |archive-date=9 February 2019 |archive-url=https://web.archive.org/web/20190209124448/http://www.gosport.gov.uk/EasysiteWeb/getresource.axd?AssetID=2645 |url-status=dead }}</ref> Following the disbanding of the UK's [[Coastal Artillery]] service, the battery of the fort was disarmed in 1956. At the same time, with the Submarine Service set to take on responsibility for the [[Polaris (UK nuclear programme)|UK's nuclear deterrent]], HMS ''Dolphin'' underwent a major expansion: a row of new large accommodation blocks was built alongside the recreation ground, to the west of the fort, looking out on [[the Solent]].<ref name=nhle1>{{NHLE|desc=Fort Blockhouse|num= 1001873|access-date=6 September 2021}}</ref> In the mid-1960s the training area around the SETT was rebuilt, with modern teaching blocks replacing the wooden huts formerly employed;<ref>{{cite news |title=What is happening in the Training Area? |url=https://issuu.com/navynews/docs/196506 |access-date=6 September 2024 |work=Navy News |issue=132 |date=June 1965 |page=iv}}</ref> facilities included practice [[torpedo tubes]], [[sonar]] sets, [[fire-control]], [[Ballistic missile|missile]]-launch and navigation systems.<ref>{{cite news |title=College of the Sea |url=https://issuu.com/navynews/docs/196610 |access-date=6 September 2024 |work=Navy News |issue=148 |date=October 1966 |page=ii}}</ref> New buildings continued to be added through the 1970s,<ref name="Hall2001" /> including additional accommodation and a new £2-million training facility ('[[Hugh Mackenzie (Royal Navy officer)|Mackenzie]] Block') for the Submarine School.<ref>{{cite news |title=Training the sub men of the future |url=https://issuu.com/navynews/docs/197708 |access-date=9 September 2024 |work=Navy News |date=August 1977 |page=32}}</ref>

In 1980 a new [[Royal Navy Submarine Museum]] was established just outside the entrance to HMS ''Dolphin''.<ref>{{cite journal |last1=Whitman |first1=Edward C |year=2003 |title=Royal Navy Submarine Museum Preserving a Notable Collection of Artifacts and War Stories |journal=Undersea Warfare |issue=19 |publisher=U.S. Government Printing Office |url=http://www.navy.mil/navydata/cno/n87/usw/issue_19/royal_navy.htm |accessdate=29 March 2011 |url-status=dead |archiveurl=https://web.archive.org/web/20110604181627/http://www.navy.mil/navydata/cno/n87/usw/issue_19/royal_navy.htm |archivedate=4 June 2011 |df=dmy-all }}</ref>

The Submarine School continued to expand in the 1980s with the introduction of computer simulators, and an upper floor was added to the Mackenzie Building to accommodate weapons and systems training for the new [[Vanguard-class submarine|''Vanguard''-class]] ballistic missile submarines.<ref>{{cite news |title=Diving Ahead: High tech trainers for the new generation of submarine students |url=https://issuu.com/navynews/docs/199004 |access-date=9 September 2024 |work=Navy News |date=April 1990 |pages=18–19}}</ref> At the end of the decade the [[Oberon-class submarine|''Oberon''-class submarines]], based at HMS ''Dolphin'' since the 1960s, were due to be decommissioned and by 1990 over £70-million had been spent on support facilities for their replacements, the [[Upholder Class|''Upholder'' class]]: a new generation of diesel-electric submarines. The end of the [[Cold War]], however, brought with it a reduction in defence requirements, with the threat of Soviet submarines having passed, and in the end only four (out of a planned nine) replacement vessels were built. In 1992 it was announced that the new submarines would leave HMS ''Dolphin'' and join the [[Trafalgar-class submarine|''Trafalgar'' class]] at [[HMNB Devonport]]; ''Dolphin'' would thus cease to be an operational submarine base (though it would continue to function as a training establishment).<ref>{{cite news |title=New Subs Off To Guzz |url=https://issuu.com/navynews/docs/199204 |access-date=2 September 2024 |work=Navy News |date=April 1992}}</ref> The last submarine left ''Dolphin'' in 1994. Having been declared surplus to requirements in 1996,<ref>{{cite news |title=New Direction For Dolphin |url=https://issuu.com/navynews/docs/199609/3 |access-date=2 September 2024 |work=Navy News |date=September 1996 |page=3}}</ref> HMS ''Dolphin'' was formally decommissioned in 1998; the RN Submarine School (now under the aegis of [[HMS Raleigh (shore establishment)|HMS ''Raleigh'']]) departed for [[Torpoint]] the following year.<ref>{{cite web|url=https://www.victorianforts.co.uk/pdf/datasheets/blockhouse.pdf|title=Fort Blockhouse|publisher=Victorian Forts|access-date=1 September 2021}}</ref> 

After the decommissioning, control of the fort's jetties passed to the [[Queen's Harbour Master]] (who managed them on behalf of the [[HMNB Portsmouth|Naval Base]] commander).<ref name="NavyNews1998" />

====Coastal forces (1914-1966)====
[[File:'Mine Sweepers waiting for the fog to lift'; off Fort Blockhouse, Portsmouth RMG PW1146.jpg|thumb|left|'Mine Sweepers waiting for the fog to lift': naval launches moored off Fort Blockhouse (by [[William Lionel Wyllie|W. L. Wyllie]], c.1916).]]
During the First World War a base for [[coastal motor boat]]s had been established on [[Haslar Creek]], alongside Fort Blockhouse. It closed after the Armistice in 1918, but reopened in 1921; for a time it was placed under the command of HMS ''Dolphin'', but in 1926 it was separately commissioned as {{HMS|Hornet|shore establishment|6}}.<ref name="Brown2005">{{cite book |last1=Brown |first1=Paul |title=Maritime Portsmouth |date=2005 |publisher=The History Press |location=Stroud, Gloucs. |pages=149–153}}</ref> ''Hornet'' closed in 1936 and the site was leased to the [[Royal Air Force Marine Branch]]; but at the start of the Second World War it was recommissioned as HMS ''Hornet'' and served throughout the war as a [[Coastal Forces of the Royal Navy|Coastal Forces]] base. By 1943 forty-eight [[motor torpedo boats]] were stationed there, along with smaller numbers of [[Motor launch (naval)|motor launches]] and [[motor gunboat]]s. After the war ''Hornet'' continued in commission until September 1957, when the Coastal Forces division was disbanded; however a small residual 'Coastal Forces Trials and Special Service Squadron' was retained for a time, as part of HMS ''Dolphin'', and provided with two new [[Brave-class patrol boat]]s.<ref name="Brown2005" /> The site then came to be known as 'Dolphin 2'.<ref name="Hall2001">{{cite book |last1=Hall |first1=Keith |title=HMS Dolphin: Gosport's Submarine Base |date=2001 |publisher=Tempus Publishing |location=Stroud, Gloucs. |page=113}}</ref>

By 1964 the former ''Hornet'' site was largely disused. That year a [[sailing club]] (Hornet S.C.) was established there for serving and ex-Royal Navy personnel, with shore facilities, including a clubhouse in the former wardroom, and marina facilities on the creek. In 1972 the Royal Navy established a 'joint services adventure sailing training centre' alongside the sailing club, which runs offshore sail training for serving members of the armed forces.<ref name="HSSC">{{cite web |title=History |url=https://www.hornetservicessailing.org.uk/the-club/history |website=Hornet Services Sailing Club |access-date=28 August 2024}}</ref>

====SETT training facility (1998-2020)====
[[File:Submarine Escape Training, Gosport. MOD 45143837.jpg|thumb|right|The SETT viewed from above (2004).]]
The Royal Navy Submarine School (RNSMS) remained at Fort Blockhouse until 23 December 1999, whereupon it moved to [[HMS Raleigh (shore establishment)|HMS ''Raleigh'']] in Cornwall. Nevertheless, the RNSMS still continued to make use of the Submarine Escape Training Tank (SETT) at Fort Blockhouse for a further twenty years:<ref name="auto">{{Cite web|url=https://www.portsmouth.co.uk/news/defence/iconic-gosport-tower-used-submariners-final-time-1359757|title=Iconic Gosport tower is used by submariners for the final time|website=www.portsmouth.co.uk}}</ref> the SETT was used for pressurised training up until 2012, and then continued to be used for non-pressurised drills and teaching until it was finally decommissioned in January 2020.<ref>{{cite news |title=End of era for Gosport's iconic submarine escape tower |url=https://www.royalnavy.mod.uk/news/2020/january/09/200109-end-of-gosport-escape-tower |access-date=11 September 2024 |work=Royal Navy News |publisher=Royal Navy |date=9 January 2020}}</ref> 

Subsequently a new submarine training facility was opened in [[HMNB Clyde]].<ref>{{cite news |title=HRH Prince William opens £34m submarine training facility in Clyde |url=https://www.royalnavy.mod.uk/news/2021/june/29/210629-new-submarine-training-facility |access-date=11 September 2024 |work=Royal Navy News |publisher=Royal Navy |date=29 June 2021}}</ref>