Calshot Castle was one of Henry VIII's coastal castles that he had built to defend England from a French attack. Over the years the role of Calshot Castle developed from a defensive role into the centre of a community. Throughout its existence, the castle has provided accommodation, been a coastguard station, a major air base, a training centre, the centre of a major international air competition, as well as now being owned by English Heritage, while the buildings that surround it house an activities centre. Despite being on the end of Calshot Spit, a mile-long narrow sand and shingle stretch of land that reaches into the mouth of Southampton Water midway along the Solent, visitors can easily access Calshot Castle from land. Some of the best views of Calshot Castle, however, are from the sea – from either a yacht or the ferry to the Isle of Wight that passes close to the castle.

History

When King Henry VIII left the Catholic church in 1538, the heads of England's traditional enemies France and Spain, Francis I and the Emperor Charles V, signed a peace treaty. Offended by King Henry's actions, Pope Paul III encouraged France and Spain to invade England. In response, Henry VIII began a national castle building programme to bolster England's defenses against invasion. The area around the Isle of Wight and the Solent presented Henry with special concern¹. Portsmouth held Britain's first drydock and the Royal Navy base. Invading forces could land a substantial contingent on the Isle of Wight in preparation for a sustained invasion of the mainland; and, Southampton was England's third largest port and a rich prize in itself. Southampton's medieval castle and walls were outdated and an inadequate defence against ships armed with cannon, and so, to defend the port from an attacking fleet, Henry ordered the construction of coastal castles armed with cannon.

The Construction of Calshot Castle

The King delegated responsibility for planning the defences of the centre and the west of the Solent to Lord Admiral and Earl of Southampton William Fitzwilliam and Lord St John William Paulet, first Marquess of Winchester². After surveying the tides and landscape of the Solent, they recommended the building of four forts. They proposed two on the Isle of Wight, at Cowes³ and East Cowes, one large coastal castle on the end of the Hurst Spit⁴, a promontory of land that guards the narrowest point in the Solent, as well as a coastal castle to be built on Calshot⁵ Spit, a thin spit of land on the west bank of Southampton Water that guards where Southampton Water, the tidal river from Southampton, meets the Solent, the stretch of water that separates the mainland from the Isle of Wight.

Fitzwilliam and Paulet identified the specific location for Calshot Castle on 18 March, 1539 and by the end of 1540 construction on the castle was completed. The speed of the build shows the importance attached to it. Despite the speed, Calshot Castle is incredibly well-made, designed as state-of-the-art in castle technology. The stonework is laid out and put together with precision and skill. Calshot Castle has a thick central circular tower with three tiers of cannon behind a thick circular parapet, all designed to deflect cannon balls shot at the castle and withstand any bombardment from enemy ships. The dissolved monasteries at Netley Abbey and Beaulieu Abbey⁶ provided the stone and other materials used to build the castle. Although far smaller and simpler in design than the largest Henrician⁷ castles of the period, Calshot Castle was still listed as one of the ten 'great castles' Henry VIII planned of the 30 castles, forts and blockhouses constructed. Calshot Castle mustered 36 cannon with a garrison consisting of a Captain, a deputy, eight gunners and five soldiers.

Castle Description

Calshot Castle consists of a polygonal curtain wall containing 15 gun emplacements and an essentially octagonal keep that rises to two cylindrical floors at the top. A bridge provides ingress to the castle over a wet stone-lined 16-sided moat 9 metres wide and 2.5 metres deep. Visitors to the castle could gain access only one way, across the drawbridge, now replaced with a metal bridge, and through a gatehouse, later expanded to house a range of buildings.

The Curtain Wall

The curtain wall originally consisted of 16 sides containing 15 gunports, which were arched over, and the drawbridge on the remaining side. A high wall protected and covered over the gunports; but, in 1774 the height of the wall was lowered and the covered gunports converted into open-topped embrasures. Firing steps sit between the embrasures to allow defenders to fire handguns, such as muskets and rifles, at attackers. Victorian modification in 1896 converted five of the original gunports into emplacements for the castle's searchlights. Two of HMS Tiger's signalling lamps now stand where the searchlights once stood to give an impression of their appearance, as well as two replica Tudor cannon positioned to defend the entry to Southampton Water.

Gatehouse

The design places the castle's only means of entrance through the gatehouse on the western side of Calshot Castle. The gatehouse originally had a simple layout. It had one room over the gate passage and a crenellated defensive roof level above. The gateway benefited from multiple layers of protection, including a drawbridge, a portcullis operated from the first floor room, and two gunports, like arrow loops, for small hand-held weapons. Historians believe the gate of the castle's gatehouse may once have displayed Henry VIII's coat-of-arms.

In the 1770s the need for more accommodation led to considerable expansion of the gatehouse, initially for the castle's governor. Modifications ensured no compromise in the defensive capability of the structure, as only one window looks out from the castle – all the others overlook the castle's courtyard. The refurbishment both expanded and increased the height of the gatehouse; and converted the crenel in the battlement overlooking the castle's drawbridge into an opening for a new second floor window. The expansion included the addition of one gunport on either side of the main passageway – these two gunports are the only ones to survive with their original Tudor shape, as the other gunports underwent conversion into embrasures during the lowering of the curtain wall in 1774. In 1896 the gatehouse was extended once more, with a cookhouse, latrine and storerooms added to the gatehouse's south side.

At the time of writing, the public can only access the rooms on the ground floor of the gatehouse, which house the castle's gift shop and displays on the castle's history.

The Keep

The keep is the castle's dominant structure. The keep is octagonal on the bottom floors but cylindrical above. The ground level of the keep's exterior has a pair of recesses on each side – these originally housed shot and powder for the guns mounted in the courtyard's curtain wall. The remains of a bracket adorn the outer wall of the castle that once held the castle's bell and the royal shield.

The basement, accessible through a new staircase and doorway, underwent extensive modification in 1896. It is believed that it originally resembled the vaulted basement at nearby Hurst Castle, as the same team of builders built it, though to a smaller design. The basement originally housed the castle's provisions, including food, water, fuel and ammunition. Unlike other castles, Calshot Castle did not have its own well, as all water in the area would be contaminated with the salt water from the Solent. In 1896 the basement was converted to house oil engines and generators for the castle's searchlights. The basement's floor was dug out, which initially made the basement higher until the basement roof was remade in a strong concrete layer in a lower position. In 1907 the oil engines were removed to an outbuilding outside the castle, and the basement once again housed the ammunition for the castle's guns.

The first floor, accessible up a small flight of stairs, has the appearance of a 19th Century barrack room, complete with metal extending bed frames and shelves for personal possessions. The room's floor sits two feet lower than it did in 1540; when the basement was converted in 1896 the basement's new concrete ceiling was at a lower height than previously, allowing the first floor to have a lower floor. Some of the original Tudor stonework in this room is red, evidence of the fire in the 1580s that devastated the keep.

The second floor of the keep now houses an information display about the Schneider Cup. This floor originally held some of the castle's heaviest guns. However, the Victorians converted the floor into a barracks. There is a garderobe built into the wall on the southeast side.

The roof has undergone extensive changes. The curved parapet designed to deflect shot and the gun embrasures were replaced in 1770 by a universal height parapet designed to protect soldiers armed with muskets and rifles. In 1907 the parapet was again modified to hold two 12-pounder QF guns on raised platforms, with ammunitions lockers beneath and the present flat concrete floor laid. The 12-pounder QF gun emplacement on the castle roof is not the original. Although the gun is the same, the mounting and shield differ having originally served as part of a naval vessel's armament.

Neighbouring Coastal Castles

In 1544 Southampton acquired additional defences from two further castles on Southampton Water. The first, St Andrew's Castle, was built where the river Hamble joins Southampton Water. The site of this, to the west of Hamble Common, has completely eroded away, but it is believed to have been more of a blockhouse than an actual castle, consisting of a tall square tower behind cannon on a lower semicircular bastion facing the sea.

Halfway between St Andrew's Castle and Southampton, Netley Castle was built on William Paulet's own land, using the stone from neighbouring Netley Abbey. This was similar in design to a smaller Southsea Castle and still exists now, although almost entirely altered in its new role as an old people's home.

Up to the Civil War

After the threat of invasion subsided, with the Battle of the Solent and invasion of the Isle of Wight in 1545, Calshot Castle fell into gradual disrepair. By 1559 only ten cannon remained fully serviceable. Soon after, Calshot Castle suffered a serious fire in the keep, so fierce it even reddened the stone walls. In 1584, under Queen Elizabeth I, the castle underwent repairs, with new floors constructed in the keep to replace those consumed in the fire, with 127 trees from the nearby New Forest felled for the purpose.

By the time of the invasion threat from the Spanish Armada, the castle stood fully prepared, with a garrison of a master gunner and seven gunners.

In 1642, during the Civil War, Parliamentary forces, under the command of Captain Swanley, captured Calshot Castle, as well as Netley Castle and St Andrew's Castle. He ordered removal of the cannon from these castles and used them to threaten Southampton to surrender and pledge allegiance to Cromwell. While Roundhead forces demolished Netley and St Andrew's Castles to prevent their use by the Royalists, Calshot Castle and its role in protecting the approach to Southampton Water proved too important for the same to happen. Instead, money was spent on repairing the castle, returning it to full active status.

After the Civil War

After the Civil War, various threats from France and Spain ensured that Calshot Castle remained fully prepared. During the War of Spanish Succession, in 1702-13, Calshot Castle housed 25 operational cannon. After the Scottish Rebellion, in 1715, Calshot Castle was surveyed by Captain Talbot Edwards, charged with maintenance of the coastal defences of Portsmouth, the Isle of Wight and the Solent. In the aftermath of these conflicts, in order to save costs, the castle, along with other coastal defences, was kept at a maximum of half its normal complement; and so, by 1725, only 13 cannon and a garrison of a master gunner and two gunners remained.

In 1774 the first major alteration to Calshot Castle occurred. The gatehouse was extensively widened in order to create new rooms for the castle's Captain, or Governor as the Captain was now known. The alterations lowered the outer circular curtain wall, removed the gun ports and adapted them into embrasures⁸.

During the Napoleonic Wars, after Nelson's victory over the French and Spanish fleet at Trafalgar, the likelihood of any foreign invasion seemed remote, and so Calshot Castle was considered unimportant. So much so that after the Napoleonic War ended with the Battle of Waterloo, Calshot Castle became quarters for the coastguard⁹. Calshot, located halfway along the Solent and at the very tip of Southampton Water, was perfectly located for a coastguard station. The castle was used as coastguard quarters, with the commanding officer living in the tower, married men living in the gatehouse and others in the coastguard cottages later constructed nearby. In 1856 the Admiralty took over ownership of Calshot Castle, having taken over responsibility for the coastguard.

The Latter Half of the 19th Century

From the 1860s warship design underwent a revolution with the development of new technology. In 1860 HMS Warrior, the world's first iron-hulled warship, was launched as a direct response to France's ironclad La Gloire. By 1870 the first torpedoes had been developed and by the 1880s the French Navy, Britain's traditional enemy, had large numbers of fast torpedo boats. Although Britain's navy was larger and superior to that of France, concern grew that a combined French and Russian fleet could, in what was termed a 'bolt from the blue', defeat the Royal Navy in a surprise attack. To counter this perceived threat the Admiralty encouraged the development of heavy guns capable of firing faster in order to hit the speedier targets that a fast torpedo boat would offer.

In order to defend the Solent, coastal forts were fitted with new quick firing (QF) guns as well as searchlights, to prevent sneaky night attacks¹⁰. As Calshot Castle was too confined to be re-equipped with all the new QF guns required, the Admiralty had a new gun battery built just south of the castle. Built between 1895 and 1897, the battery mounted six QF guns. The castle itself housed three searchlights as well as the electricity generators. In 1907 the Navy installed two QF guns on Calshot Castle's roof.

In further enhancing the defence of Southampton Water, the Royal Navy installed a boom defence – a physical barrier stretching across Southampton Water preventing enemy ships entering undetected. This was one of the earliest boom defences in the country, composed of a line of hulks, old disused ships, secured across the mouth of Southampton Water with four towers armed with QF guns and machine guns known as 'dolphins' defending them. In 1909 a new purpose-built boom replaced the old ships. The boom stretched across from Calshot Castle, defended by aging torpedo boats. By 1910 there were ten officers and 154 other ranks stationed in Calshot to man the castle, gun battery and the 'dolphins' – of which three officers and 85 men lived in the castle itself with the rest nearby.

Calshot Royal Naval Air Station

On 28 March, 1910, the world's first seaplane flew in La Mède, near Marseilles in France, piloted by Henri Fabre. The same year, the first take-off and landing happened at the site which was to become Southampton Airport. By 1912, the year in which the first British seaplanes were built¹¹, the Admiralty were keen to explore the possibilities that aquatic aircraft had to offer and, as aircraft carriers had not yet been conceived of, visualised a network of air stations around the UK.

Sheltered and near both Portsmouth and Southampton, Calshot provided the perfect site for the waters around the Isle of Wight. The Isle of Wight played a key role in seaplane and flying boat development. It was at Cowes on the Isle of Wight that Saunders¹² built the prototype Bat Boat, Europe's first flying boat. The company named the boat after a fictional flying machine in Kipling's With The Night Mail; and, in July 1913, Saunders won the Mortimer Singer Prize for the first all-British aeroplane capable of making six return flights over five miles within five hours. It was also the world's first successful amphibious aircraft. This Bat Boat, and subsequent Bat Boats built by Sopwith with Saunders building the hulls including one that won the Daily Mail prize for the first aircraft to complete a round-Britain trip, were bought by the Royal Navy and stationed at Calshot Castle.

On 29 March, 1913, Calshot Royal Naval Air Station began, with three wooden sheds¹³ housing up to 12 seaplanes with the naval personnel housed in the nearby coastguard cottages and at Warsash¹⁴ across Southampton Water. The first commanding officer, Lieutenant Spencer Grey, commuted in to Calshot each day on his own private seaplane. At the time the First Lord of the Admiralty, Winston Churchill, had a keen interest in developing the role of the Royal Naval Air Service and purchasing aircraft for them. It is Winston Churchill who is credited with inventing the term 'seaplane'. He first took a seaplane flight from Calshot Castle on 28 August 1913, piloted by Timmy Sopwith, who later taught Churchill how to fly.

Calshot Air Station was used until the Great War for experimental work. This included trials of wireless telegraphy from aircraft and radio pioneer Guglielmo Marconi lived near Calshot Castle. When the King reviewed the fleet in July 1914, 17 aircraft flew from Calshot, passing the Royal Yacht.

The First World War War

Shortly before the outbreak of war, the RNAS reassigned Lieutenant Spencer Grey and Squadron Commander Longmore took over commend of Calshot. Calshot continued in its role as a site for the training new pilots, but also began to support the experimentation of techniques to spot U-Boats, launch torpedoes, drop bombs and fire guns as well as aerial photography. From the end of 1916, with the increase of German submarine activity, regular anti-submarine patrols began out of Calshot. There were established subordinate stations originally at Bembridge and Portland, and later at Polegate and Newhaven to combat the submarine threat. Aircraft from Calshot helped a Naval ship sink U19 on Portland Bill in 1916. On 12 August, 1917, a Wight Converted Seaplane, built by J Samuel White's on the Isle of Wight¹⁵, was the first aircraft ever to destroy a submarine when Sub-Lieutenant Mossop bombed the German U-boat UB32, for which he was awarded the Distinguished Service Cross. By the end of the war, Calshot-based aircraft had spotted 42 submarines and sunk three.

After the end of the war, the Royal Naval Air Service merged with the Royal Flying Corps to become the Royal Air Force. In 1918 Calshot Royal Naval Air Station reverted to a training role, becoming the School for Naval Co-Operation and Aerial Navigation, training in sea rescue and recovery, and the flights stationed at Calshot became 240 Squadron. On 5 February, 1922, Calshot School For Naval Co-Operation and Aerial Navigation was renamed RAF Calshot.

The Calshot Express

Calshot grew in importance during the Great War. That importance drove the construction of new buildings, especially hangars and slipways for the aircraft, and the few coastguard cottages nearby proved insufficient to their task. Instead, construction proceeded on a new camp at nearby Eaglehurst with a narrow-gauge railway built initially to help ferry supplies to the building site, but later to transport personnel.

This line, known as the Calshot Express, remained in service until the end of the Second World War, but sadly no longer exists. However one engine, Douglas, still survives and now runs at the Talyllyn Railway in Wales.

The Talyllyn Railway provided significant inspiration for Thomas the Tank Engine author Reverend Wilbert Awdry, who gave many of his narrow-gauge characters similar names to engines there. The character of Duncan in the Railway Series is based on the former Calshot Express engine Douglas. Duncan is engine 6 in Mr Percival the Thin Controller's Narrow Gauge Railway in Thomas the Tank Engine and Friends. Duncan regularly appears in Thomas and Friends from series five onwards. At the time of writing, Duncan has made notable appearances in the episodes 'Duncan Gets Spooked', 'Dunkin' Duncan' 'Duncan and the Old Mine', 'Duncan Drops A Clanger', 'Duncan's Bluff', 'Duncan Does It All' and 'Duncan and the Hot Air Balloon'. In the books by Reverend Awdry he first appeared in The Little Old Engine, book 14 in the original Railway Series, first published in 1959.

The Schneider Cup

In 1912 Jacques Schneider donated a bronze cup trophy to the Aero Club de France with the aim to promote seaplane development. The competition rules required that entrants represent their country and the winning country would host the next competition. Any country winning the Schneider Cup three times in succession would win it outright. The organizers originally intended to hold the competition annually, but occasionally this changed to every other year.

Britain had a reasonable amount of success in early years, winning in 1914 with a Sopwith biplane. In 1922 Britain won for a second time with a Supermarine Sea Lion II, designed by RJ Mitchell, who would later design the Spitfire so instrumental in the Battle of Britain. In 1923, when Britain hosted the Schneider Cup in Cowes on the Isle of Wight, America won. They repeated the feat again at the next event in 1925, in which RJ Mitchell's Supermarine S4, despite setting a new seaplane speed record of 226mph, crashed shortly before the race. In 1926 Italy won and for 1927 RJ Mitchell designed the S-5 for the competition in Venice.

In order to meet the challenge of the 1927 Schneider Cup, the RAF formed the High-Speed Flight, based out of Calshot, to practise and participate in the race. For two months they practised for the race, flying Supermarine S5 seaplanes designed by RJ Mitchell, before leaving for Venice. The S5s came in first and second places. On their return the High-Speed Flight continued practising in 1928 for the next competition, to be based at Calshot in the following year. On 12 March, 1928, while attempting to set a new speed record, Flight Lieutenant Sam Kinkhead crashed into the Solent.

The British Air Ministry commissioned Supermarine to build two more seaplanes for the 1929 Schneider Trophy race. These, the Supermarine S6, considered the direct predecessor of the Spitfire, were the first aircraft he designed powered by a Rolls Royce engine. The 1929 contest was held over the Solent and hosted at Calshot Castle, and on Saturday 7 September, 1929, over a million people watched the race, with the best vantage points on top of Calshot Castle. Flight Lieutenant Waghorn raced the S6 around the seven laps of the course at a speed of 328mph to win. Five days later Squadron Leader Orlebar flew an S6 to break the air speed record, flying at 365mph. Among those involved with organising the 1929 Schneider Cup competition at Calshot was Aircraftsman Lawrence Shaw, commonly known as Lawrence of Arabia. He worked at Calshot, and nearby Hythe, on developing high speed launches, used initially to tow disabled flying boats and later the basis for development of the air-sea rescue craft. Visitors can see the Supermarine S6 on display in the Solent Sky museum, Southampton.

In 1931 Britain had the opportunity to defend its title and win the Schneider Trophy outright. However, the world's financial position had changed. With Britain in a recession the Government could not muster the finances to develop a new aircraft for the race. The rich and patriotic Lady Houston saved the day by sponsoring Britain's team. She provided enough money for RJ Mitchell to refine his S6 aircraft, rather than develop a new one, fitting it with a more powerful engine. Two of the modified aircraft, known as the S6.B, were built and one piloted by Flight Lieutenant Boothman won the race at Calshot in 1931 at a speed of 340mph, winning the Schneider Trophy outright. Two weeks later Flight Lieutenant Stainworth flew the other S6.B at a record air-speed of 407.5mph, the first man to fly at over 400mph.

The Second World War

By the time of the outbreak of the Second World War, Calshot had undergone preparation for military duty and anti-submarine patrols. In addition, Calshot provided facilities for the repair and service of the Short Sunderland flying boats that formed the backbone of Britain's anti-submarine and pilot rescue efforts. Initially, three anti-aircraft guns mounted on a barge defended Calshot Castle itself, and plans had been prepared to sink ships in Southampton harbour, at the entrance to Southampton Water near Calshot Castle, should a German invasion attempt seem imminent.

In 1940 the military installed two 12-pounder QF guns on the roof of Calshot Castle as well as six searchlights, with two more 12-pounder QF guns and six searchlights on the opposite shore of Southampton Water, at a location known as Bungalow Battery. Three miles southwest of Calshot Castle, three 6-inch guns were installed at a site known as Stone Point Battery. These three sites made up Calshot Fire Command. Calshot Castle managed to escape heavy damage during the war despite Portsmouth and Southampton being among the Luftwaffe's top targets.

Soon after the war, Calshot's Short Sunderland flying boats came to the rescue of the German people during the 1948 Berlin Crisis, when Short Sunderlands airlifted food into Berlin and evacuated sick children to safety.

After the War

After the war the development of airports made flying boats all but obsolete. In 1953 Calshot Castle was closed as a frontline station, which was transferred to Maintenance Command, and on 1 April, 1961, Calshot Castle closed as a Royal Air Force station. A purpose-built coastguard tower was constructed next to Calshot Castle, and so the castle no longer functioned in the capacity of a coastguard station either.

Although in the 1940s flying boats continued flying commercially, the end was in sight. In 1950 BOAC flew its last flying boat from Southampton: the Princess, the world's largest successful flying boat, which first flew on 22 August, 1952. Sadly, however, although many customers had originally expressed an interest, including BOAC and the RAF, no one purchased any of the original three constructed aircraft. Between 1952 and 1967, Calshot provided storage space for two Princess flying boats, dwarfing the castle. In 1958 reports suggested the US Navy intended to order construction of a nuclear-powered version, yet in 1959 they decided to cancel. In July 1967 the Princess flying boats were taken from Calshot Castle to be scrapped.

Calshot's last involvement with flying boats occurred in the 1980s. In 1981 a Short Sandringham flying boat, named The Southern Cross, flew to Calshot after crossing the Atlantic. Restored, the Solent Sky museum now preserves this vessel for posterity in what was then the Southampton Hall of Aviation. In 1984 ML814, the last flying Sunderland of the 749 built, came ashore to Calshot for refit and restoration. Sadly it left on 20 July, 1994 and flew to Florida to join the Fantasy of Flight private collection.

Since the opening of the neighbouring purpose-built Coastguard facility, Calshot Castle has opened to the public. English Heritage manage the property, having restored it to its pre-1914 appearance.

Other English Heritage properties nearby include Portchester Castle in Hampshire as well as Carisbrooke Castle and Osborne House on the Isle of Wight.

Calshot Activities Centre

The rest of Calshot Spit, including some of the former aircraft hangars, became what is now known as the Calshot Activities Centre on 25 November, 1963. This is an educational outdoor pursuit facility. In 1964 sailing and canoeing facilities were opened followed by Britain's first indoor cycle track in 1967. Today, as well as water sports including windsurfing, the site includes sports pitches, climbing walls, ski slopes and a high ropes course.