General explanation:
History is full of interesting things, much of it can still be seen today and for this story we go back to the year 1533, Henry VIII was the King of England and broke openly with the Pope of Rome ... and the rest is history ... but I will take out one little piece of the consequences and talk about it in detail. The military problem!
The world was a very different place back then and Henry realized that the Pope, together with the King of France could well be getting ready to invade England, and the only of doing that would be by boat, crossing the Channel or North Sea, luckily for him, Naval power was still in its infancy, so it would take a while before any invasion fleet would be ready for action. Henry decided to organize the defense of England, before him this was basically left to local Lords in outdated castles and although there were some forts and defensive castles, they were simply not up to the the task of defending England. In those days there was still this idea of castles ruling the countryside around them, however, by this time there was gunpowder and most castles would be easily breached by artillery fire. Henry knew that and designed a whole new plan to defend his country, this plan was called a "Device".
The device meant the start of building mighty military forts all along the coast, concentrating on important seaways and ports but also some on defenseless coastlines, let's have a look at the ones that were built on this list with some side notes:
Brightlingsea Blockhouse - lost due to coastal erosion
Brownsea Castle - has been converted and is now a hotel
Calshot Castle - open to public
Camber Castle - ruined and open to public
Deal Castle - open to public
Devil's Point Artillery Tower
East Blockhouse - never completed and only ruins are left
East Cowes Castle - lost
East Tilbury Blockhouse - lost but some remnants could survive in the Thames mud
Gravesend Blockhouse - demolished in 1844, only foundations remain
Great Turf Bulwark - lost
Great White Bulwark of Clay - lost
Harwich Blockhouses - there were 3, 2 were demolished and 1 has been lost
Higham Blockhouse - demolished
Hull Castle and Blockhouses - demolished in 1864
Hurst Castle - extensively rebuilt several times throughout history, open to public
Langar Point - lost and replaced later by Landguard Fort
Langar Rode
Little Dennis Blockhouse
Little Turf Bulwark - lost
Mersea Fort
Milton Blockhouse - lost
Netley Castle - rebuilt several times and currently residential flats
Pendennis Castle - open to public
Portland Castle - open to public
St Andrew's Castle - destroyed by the sea, only a few parts survive
St Catherine's Castle - open to public
St Helens Bulwark - lost
St Mawes Castle - open to public
St Osyth Blockhouse - lost
Sandown Castle - Hampshire, demolished in 1631
Sharpenrode Bulwark - Fort Victoria was later built over this site
Sandsfoot Castle - only ruins are left
Sandgate Castle - rebuilt as a Martello tower
Sandown Castle - Kent, lost, some parts remain and are incased in the new sea wall
Southsea Castle - open to public
Walmer Bulwark - lost
Walmer Castle - open to public
West Blockhouse - destroyed to make way for West Blockhouse Fort in 1857
West Cowes Castle
West Tilbury Blockhouse - demolished in 1868
Yarmouth Castle - open to public
Now let's have a look at the locations on a map (at right - taken from Wikipedia.org). This map shows all the original forts and other defenses, some of those don't exist anymore, but in the next chapter I will go into detail of each and every one of those that I have been able to visit and document. Some are completely intact, others are ruined or even mostly destroyed as you will find out throughout this series of blogposts. I usually start my journey into the UK coming from either the Dutch or the French coast, meaning that I arrive at Dover, Harwich, Portsmouth or Hull. The first thing that comes to mind is the defense of all major ports, in most cases you will indeed find some kind of coastal defenses, however mostly these date from earlier or later times, some of these will be mentioned here as well but for the purpose of this blog, we will concentrate only on the original Device Forts.
Number 1: Calshot Castle
Calshot Castle was completed in 1540 on the so called "Calshot Spit", a long landmass located on the edge of Southampton water where it meets the Solent (see map on the left), a vital shipping lane, even then! The Solent was heavily defended by the Device forts and Calshot was one of several forts along the way. It was designed with a circular keep, a gatehouse, a curtain wall and a moat that was filled up with water, although today it is usually dry.
The castle was heavily armed for the time with a staggering 36 guns on 3 different levels, 2 levels within the keep and the 3rd within the curtain wall. A lot can be written about the constant re-development of the site around this castle but focusing on the castle itself, we can say that it remained in some kind of military role up to World War 2 when the RAF had a station on the site called "RAF Calshot" a base for Seaplanes had already been there from World War 1 and this was now part of the RAF base. Even after the war the RAF station continued to operate Short Sunderland Flying Boats from this base, however, the base was closed in 1961. In 1983 the castle was taken over by English Heritage (https://www.english-heritage.org.uk/visit/places/calshot-castle/) and restored to its former appearance, removing most of the later additions. The site and castle are open to the public. My biggest interests on this site come from 3 different angles, one being the history of the castle itself, secondly the historic aspect surrounding the legendary flying boats from the earliest beginnings up to the large Sunderlands patrolling in World War 2 and after, and third ... the viewpoint! All ships sailing to and from Southampton have to pass by Calshot before making an important turn towards Portsmouth or sometimes The Needle to be able to sail off into the open sea.
This makes Calshot a prime location when you want to photograph passenger ships from major cruise lines, the last remaining ocean liner Queen Mary 2 - seen right as I photographed her from Calshot - of Cunard line or local ferries from Red Funnel Ferries going to the Isle of Wight, especially leaving ships are easy to photograph because the light comes from a good direction in the afternoon and evening, I even managed to launch my drone there once, however, winds can be pretty strong on the open area viewing the water, so be prepared if you would visit the place, the roof of the keep is a perfect viewing platform during the day as well.
Calshot Spit as it appears today with the castle clearly visible - photo taken from onboard P&O Oriana in 2019.
A series of photos I took on various occasions: