Editing Fort Blockhouse (section)

===Modernised fort (1667–1877)===
[[File:Portsmouth RMG F1960.tiff|thumb|right|Map of Portsmouth c.1668 showing the chain defence across the harbour entrance; Gosport Point, with de Gomme's battery, is to the right on this [[South-up map orientation|south-up map]].]]
In 1665, during the [[Second Dutch War]], Sir [[Bernard de Gomme]] was commissioned by [[Charles II of England|Charles II]] to improve the Portsmouth defences.<ref name="Saunders1989">{{cite book |last1=Saunders |first1=Andrew |title=Fortress Britain: Artillery Fortification in the British Isles and Ireland |date=1989 |publisher=Beaufort Publishing |location=Liphook, Hants. |pages=91–92}}</ref> Two years later he installed a new L-shaped battery on Gosport Point (where the blockhouse had formerly stood): it consisted of a row of eighteen guns facing south-east, to protect the seaward approach to the harbour, and two more guns pointing south-west, so as to protect the landward approach to the battery (which was along a narrow spit of land).<ref name="HGateway">{{cite web |title=Historic England Research Records: Fort Blockhouse |url=https://www.heritagegateway.org.uk/Gateway/Results_Single.aspx?uid=462035&resourceID=19191 |website=Heritage Gateway |publisher=Historic England |access-date=19 August 2024}}</ref> The following decade an [[Point Battery|eighteen-gun battery]] was constructed by de Gomme alongside the [[Round Tower (Portsmouth)|Round Tower]] on the Portsmouth side of the harbour entrance, matching the battery on the Gosport side.<ref name="Saunders1989" /> To the north, on the west side of the harbour, de Gomme built two square defensive towers, Charles Fort (at Gosport) and James Fort (on [[Burrow Island]]), which were completed by 1679; while on the landward side he began constructing a bastioned trace around the town of Gosport in 1678.<ref name="auto1">{{Cite web|url=http://www.fortified-places.com/gosport/default.htm|title=Fortified Places > Fortresses > Gosport|website=www.fortified-places.com|access-date=29 July 2020|archive-date=9 January 2020|archive-url=https://web.archive.org/web/20200109153124/http://www.fortified-places.com/gosport/default.htm|url-status=dead}}</ref> 

[[File:Plan of Portsmouth (detail, showing Fort Blockhouse) 1750.jpg|thumb|250px|left|Detail of a 1750 map by [[John Peter Desmaretz|J. P. Desmaretz]], showing Fort Blockhouse (left) in relation to the [[Round Tower (Portsmouth)|Round Tower]] and battery on the other side of the entrance to the harbour.]]
An inspection in the early 18th century, however, found that the defences had fallen into poor condition; Captain Talbot Edwards (who, as [[Royal Engineers|Second Engineer]], was made responsible for surveying the Portsmouth fortifications) said of the battery that 'this work like the rest is all gone to ruine'.<ref name="HGateway" /> Between 1708 and 1714 the battery was completely rebuilt to create a bastioned fort, with a renewed seaward-facing open-air battery to the south-east and significant defensive earthworks to the south-west.<ref name="nhle1" /> The shape of the 18th-century fort can still be discerned and surviving elements of the 1708 works are the oldest still present on the site.<ref name="2007PeninsulaCAA" /> The entrance to the fort on the south-west side consisted of a tall gatehouse flanked by two [[demi-bastion]]s;<ref name="nhle1" /> the gatehouse was demolished in the 1960s, but its keystone survives on site,<ref name="nhle4">{{NHLE|desc=Former Gatehouse Datestone, Fort Blockhouse|num= 1469578|access-date=22 August 2024}}</ref> decorated with the arms of the [[Board of Ordnance]] and inscribed ''[[Anno Domini|Anno]] 1708''.<ref name="Slight1838" /> The fort was surrounded by a moat on the south-west and south-east sides, the former crossed by a bridge which was protected at its far end by a stone [[redan]] and angled outer [[Earthworks (engineering)|earthworks]]. To the north the fort was enclosed by wooden [[palisade]]s which formed a [[bastion]] at the northernmost point. In the 1750s the fort was described as being armed with twenty-one 18 pounder guns and three 6 pounders.<ref name="nhle1" />

[[File:Gezigt van de stad en haven van Portsmouth - btv1b53010608c.jpg|thumb|right|upright=1.6|An 18th-century view of Portsmouth from Fort Blockhouse]]
Beyond Fort Blockhouse the Gosport fortifications were extended northwards in 1757 in order to enclose the [[Royal Clarence Yard|Weevil brewery]] (which had been acquired by the [[Victualling Commissioners]] a few years earlier). New defences were constructed for Gosport in 1778, with the bastioned [[Fort Monckton]] situated on the ground that had been occupied by Haselworth Castle in the Tudor era.<ref name="auto1"/> Further renovations took place from 1797 to 1803, amid fears of French invasion. This created a line of bastions defending Gosport all the way from Blockhouse Point up to [[Forton Lake]] on the far side of the town, with French prisoners of war making up a part of the construction workforce.<ref>{{cite book|url= https://books.google.com/books?id=TE-DDQAAQBAJ   |title= Hell Upon Water Prisoners of War in Britain 1793–1815|first=Paul|last= Chamberlain|year=2016|publisher=The History Press|isbn=978-0750980531}}</ref> These developments rendered some of the older works redundant:<ref>{{cite web |title=Historic England Research Records: Fort James |url=https://www.heritagegateway.org.uk/Gateway/Results_Single.aspx?uid=c5966cc6-9726-4a49-9bf5-1f8be0b29039&resourceID=19191 |website=Heritage Gateway |access-date=22 August 2024}}</ref> both James Fort and Charles Fort were allowed to fall into ruin in the early 19th century.<ref name="Slight1838">{{cite book |last1=Slight |first1=Henry |title=The History of the Town and Borough of Gosport |date=1838 |location=Portsmouth |pages=6–7 |url=https://archive.org/details/historyofportsmo00slig/page/n183/mode/2up |access-date=22 August 2024}}</ref> 

[[File:Fort Blockhouse (geograph 3348716).jpg|thumb|left|The South Casemates of 1845–48 represent the third reconfiguration of de Gomme's 21-gun battery; the overgrown sandy area in front is the former moat.]]
By 1805 Fort Blockhouse was armed with fifteen 36-pounder and fifteen 18-pounder guns.<ref name="Maurice-Jones1959">{{cite book |last1=Maurice-Jones |first1=Col. K. W. |title=The History of Coast Artillery in the British Army |date=1959 |publisher=Royal Artillery Institution |location=Woolwich |page=97}}</ref> In 1813, as noted on a preserved datestone,<ref name="nhle4" /> the fort began to be remodelled: the west demi-bastion was extended to the north in 1817-20 and not long afterwards the sea battery was rebuilt with thirteen covered [[casemates]] housing 32-pounder guns.<ref name="HGateway" /> The upper part of the battery was strengthened and widened in 1845-48, providing space on the [[terreplein]] for a further thirteen guns to be mounted ''[[Barbette|en barbette]]''. This work was part of a substantial rebuilding, which saw the creation of the north bastion: a rounded structure with casemates, built of red brick and fronted in limestone, with upper and lower batteries which provided a field of fire over the harbour.<ref name="2007PeninsulaCAA" /> It was linked, to the west bastion on the one hand and to the sea battery on the other, by a pair of long brick-built casemated buildings: the former providing accommodation for officers,<ref name="nhle2">{{NHLE|desc=Thames Block, Fort Blockhouse|num= 1470250|access-date=22 August 2024}}</ref> the latter for [[Other ranks (UK)|other ranks]].<ref name="nhle3">{{NHLE|desc=Arrogant Block, Fort Blockhouse|num= 1469940|access-date=22 August 2024}}</ref>

[[File:Richard Beavis - Block House Fort, Gosport, Hampshire - B1975.4.41 - Yale Center for British Art.jpg|upright=1.6|thumb|right|19th-century watercolour painting of the fort by Richard Beavis, showing guns mounted on top of the sea battery.]]
The 18th-century fortifications of Gosport were considered obsolete by the 1859 [[Royal Commission on the Defence of the United Kingdom]]. While the commissioners did not recommend any changes to Fort Blockhouse, nor were its armaments updated: in 1867 it was still armed with 32-pounder [[smooth-bore]] cannons.<ref name="HGateway" />