A History of the Sloop
The history of the Sloop is somewhat complicated but worth a look to understand the terminology and usage in the RN. Originally a Sloop was a single masted vessel with one main sail and one headsail, known as the “Bermuda Rigged Sloop” after the Design Yard, this class is still very popular due to modern lightweight sails; but in the days of yore was only suitable for small vessels due to the difficulty in handling large sails. Larger boats carried extra sails and masts to cut down the sail weight of individual sails.
Besides the Bermuda Rig the Gaff Rig was also used, this uses a four cornered mainsail, as opposed to the more usual triangular sail. Essentially the Gaff employed two booms, one at the top of the sail, and one at the bottom, to greatly increase the area of sail deployed. Gaff Rigged Sloops increased the amount of sail area available

Early in the 1700’s the RN operated single masted armed Sloops. Typical is HMS Jamaica with 14 guns, a greatly increase bow sprite to allow a Jib as well as two foresails and three square sails. Although termed a Sloop, or more correctly a “Sloop of War” they differed considerably from the conventional merchant Sloop and the mixture of sail types would be typical of future Sloops.

Although the single masted Sloops were very effective they were demanding on manpower and as the century wore on and war demands reduced crews, two masted Sloops became the norm, ignoring the civilian convention to change the class name to Cutter. The two masted versions were usually Ketch or Snow rigged. The Ketch carried the conventional triangular sails and the Snow was the mix of gaff mizzen, square sails and triangular foresails.

This mix of smaller sails rather than two large ones made it easier to handle with a reduced crew.About the mid 1700's the RN began to operate three masted Brig Rigged Sloops, these became known as Ship Rigged Sloops, the classification settled into a Brig being a two master and a Sloop being three masted. The difference between a Ship Rigged Sloop and a Frigate was one of armament, generally anything below 22 guns was a sloop, above it the ship was a Frigate.

Brigs and Sloops became the preferred vessels for convoy escort work, leaving the heavier armed Frigates free for Fleet Duties.

These small ships were comparatively heavy armed, particularly when equipped with light weight carronades, which were highly effective at close range. With a fraction of the crew of a Frigate or Ship of the Line they became the work horses of the RN.

Pax Brittanica
Around 1830 the RN adopted the French Classification of Corvette, briefly. A Corvette was a small Frigate, usually employed as a Blockade Runner.

Ship Rigged Sloops were re-classified as Corvettes.

About ten years later the Sloop Class returned, this time as steam driven paddle wheel ships also known as "Steam Packets" copying the civilian designation.

These new Sloops were the Gunboats of the Empire, deployed throughout the colonies to combat pirates and insurgents. All carried a full rig of sails as well as a steam engine, usually the horizontal beam type. The wood hulls were replaced with iron on wood frames, about the same time the Screw Propeller began to replace the Paddle Wheel.

It was the age of Gunboat Diplomacy, when trouble stirred in the vast empire the Royal Navy would be there, bringing troops, supporting them with great guns. In 1892 Kipling would write:

Come you back to Mandalay,
Where the old Flotilla lay:
Can't you 'ear their paddles chunkin' from Rangoon to Mandalay?

Wherever there was sufficient water to float a boat the Royal Navy ruled. Or at least it seemed that way.

In 1904 the slow wind of change would become a hurricane, but for now, in 1889 the Royal Navy still basked in the glow of Trafalgar and tried to forget the humiliations dealt out by the Americans in the War of 1812, trade between far flung colonies had to be defended against pirates and despots, and ships like the Paddle Schooners did the job, they were often referred to as Iron Clads as they swapped wood planks for iron plates. It could be argued sails were retained due to the unreliability of the new engines, but even heavily armoured battleships carried masts and sails which had no hope of every driving the ship. The sails were just a tradition as solid as the iron hulls that were cladding the Fleet.

In 1889 the first all metal Sloop appeared, HMS Beagle, her hull was made entirely from copper sheathed steel, no wooden frames at all. The Steel Sloop had been born.

Notes on Ship Classification
Class names usually follow the first of Type as in the "Leander Class" but it is not a formal designation, more a convenient method of grouping and identifying ships.

The formal method for the Royal Navy had been by Rating, such as "Sixth Rate" and sub rated by gun numbers, such as Sixth Rate of twenty-eight guns. In 1900 Jane's "All The World's Fighting Ships" introduced a new rating system divided into two groups: Armored and Partially Armored and sub-divided each into ratings.

Under this new system the RN Sloop became a Partially Armored Sixth Rate, this indicated the ship's armor served no fighting purpose. In other words it was a ship built of metal for it's own sake, a new concept since most ships were essentially still wood with metal armor added on.

In case things were not complicated enough the RN further rated it's ships so that a Sloop, or Destroyer, for instance could be 1st, 2nd or 3rd class depending on it's capabilities, which might relate to serviceability as much as armament. Janes further attempted to group ships into Classes based on design, in some cases these were later revised. For example the Icarus Class Sloop listed in the 1900 edition of Jane's includes: Icarus, Melita, Racer, Alert, Torch, Algerine, Phoenix, Condor, Rosario, Sheerwater, Vestal, Mutine, Rinaldo, Espiegle, Fantome and two others planned but not as yet named, they would become Merlin and Odin. A building program covering over fifteen years.

However in the 1919 edition of Jane's, Espiegle and Odin are listed as Cadmus Class, yet HMS Cadmus was built in 1903, long after the others. In short the classing of ships is an informal method and should not be taken as some gospel means of identifying identical ships. It is also worth remembering that Jane's Fighting Ships did not start life as an encyclopedia of warships, it was the scoring system for Navy Trump Cards!

Beagle Class 1889
The Beagle Class comprised two ships: Beagle and Basilisk. Although very similar to previous Iron Clad Sloops they were a significant advance in having an all steel hull encased in copper.

Both ships spent much of their service life on the South Atlantic Station, based at Freetown, Simonstown and Port Stanley in the Falklands.

They were twin screwed from a single triple expansion, three cylinder steam engine and carried a Barquentine sail rig.

Initial armament was eight 5" 50 Pounder guns but these were replaced with eight quick firing 4.7" guns in 1900. These were mounted in broadsides, four to each. These were early replacements for muzzle loaders and still used gunpowder charges to propel a 50lb shell. In later life these guns would have been replaced with 4.7" Quick Firing Guns with smokeless Propellant. The term Quick Firing at the time referred to metal cased propellant as opposed to bagged powder.

Both ships were de-commissioned in 1905, Beagle scrapped and Basilisk sold as the Maggie Grech and scrapped in 1921.

Alert Class 1894
In 1894 Two more Sloops enter service: HMS Alert and HMS Torch. These are actually lighter vessels than the Beagle Class and only single screwed, they are in fact part of an earlier Icarus Class, but they later are segregated into just the Alert Class of two ships.

These carry Six 5” and Four Three Pounder Guns.

The earlier ships in the Icarus Class are later grouped into the Mariner Class. Note that Alert is listed in some sources as HMS Albert, as usual I am taking Jane’s as the authority that she was actually the Alert.

Alert and Torch are in improvement on the earlier Icarus Class in that they are true steel hulls and are fitted with the more efficient vertical type steam engines. Both ships were Barquentine rigged.

Alert was taken out of moth balls to combat gun running in the Persian Gulf and at the outbreak of WWI and was refitted as a depot ship to support the river gunboats operating up the rivers of the gulf, her logs record the taking on of casualties and ferrying replacements, stores and ammunition to the river gunboats. Their armament was apparently reduced in later life to four 4” Guns, 4 3Pdr and three machine guns.

Phoenix Class 1895
Again in 1895 two more Sloops enter service, initially listed as Icarus Class but later as Phoenix Class, the two ships are HMS Phoenix and HMS Algerine. These are heavier than Alert and Torch at 1050 Tons.

Armament eight 5” Guns and four 3 Pdrs. The Phoenix Class are also only fully rigged on the foremast with fore and aft sails on the main and mizzen, an arrangement known as Barquentine.

They took features from both the earlier Alert Class and the Beagle, they were twin screwed with vertical three cylinder triple expansion steam engine.

Phoenix had a short career, she was sent to the China Station and served during the Boxer Rebellion, based at Hong Kong. But in 1906 she was struck by a Typhoon while alongside a coaling pier in the harbor and sank.

The wreck was raised and sold for scrap the following year. Algerine served with her sister ship in the Rebellion and saw action at the Taku Forts. She was then transferred to the Pacific Station based at Esquimalt until the outbreak of war when her crew were stripped to man HMCS Niobe. She went on to act as a depot ship until sold in 1919 as a salvage ship, but was herself wrecked in 1923.
Condor Class 1898-1900
HMS Condor and HMS Rosario entered service in 1898, at first still classed as the ubiquitous Icarus Class, but later given their own Class. Displacing 980 Tons they were similar to the Phoenix Class in that they had twin screws from a single engine and were Barquentine rigged. Condor sank in a gale on her first commission in 1901and all hands were lost, no wreckage was ever recovered. An enquiry found the sail outfit to blame and the other sloops were stripped of their sails within a few years of the incident. It says much for the RNs reluctance to let go of Wind Power that this did not happen at once!
Condor and the remaining Sloops were outfitted with six 4" guns and four 3 Pdr's from build as the RN began to concentrate on speed of firing rather than weight of metal fired. Equipped with Belleville Boilers they were rated at 13.25 Knots.

Prior to her loss Condor was based at Esquimalt on the Pacific Station. HMS Rosario was placed on the China Station based in Hong Kong until she was converted to a Submarine Depot Ship in 1913.

Four more ships of the Class were added to the Fleet in 1900, these were the Mutine, Rinaldo, Shearwater and Vestal. Rinaldo and Vestal both saw service in WW1 but with a reduced armament of four 4" guns, four 3 Pdrs and a machine gun (probably Maxine).

In general we see a reduction in the main armament of all this class during WWI, almost certainly to reduce top weight to make them more seaworthy in their role as Convoy Escorts.

Cadmus Class 1901-1903
The Cadmus were a class of six ships that were the last of the Empire Gun Boats/Sloops. Bizarrely HMS Cadmus herself was the last to be built, the first was in fact HMS Espiegal.

They displaced 1070 Tons with a complement of 112-121 with six 4" guns and four 3 Pdrs, very similar to the previous Condor but carried Barquentine Sail Rig from Build They carried about two hundred tons of coal and had a 3,000 Nm range at a cruising speed of 10 Knots with a maximum speed of just over 13 Knots.

The ships were: Espiegal, Fantom, Merlin, Odin, Clio and Cadmus. Uniquely of these pre-war sloops they are noted in Jane's as carrying three machine guns, almost certainly these would have been Maxim Machine Guns, though which type is debatable, a larger bore weapon was developed for Naval Service just before 1900, firing a one pound shell it was nicknamed the "Pom-Pom" and gave it's name to an up-rated 2 pdr version used extensively in WWII.

According to HMS Espiegle's log in 1921 her armament is listed as:

"On fxle; 2 4” QF Pedestal Mounting; On poop; 2 4” QF Pedestal Mounting; On fxle C.L.; 1 3pdr Hotchkiss; In waist: 4 3pdr Hotchkiss; 2 maxims; 2 Lewis Guns."

Espiegal and Odin were both reduced to four 4" guns before seeing service in WW1.
Twilight of Empire
1903 was the swan song of the Great Colonial Gunboats. No more would be built and by 1905 with the Royal Navy being swept by reform and radical changes in the world strategic scene, most of existing Sloops would be scrapped, relegated to depot ships or mothballed.  The designation of Sloop would not be applied to any ships built after Cadmus until the war.

Only a desperate shortage of ships would see some of Sloops revived in WW1, some would even see action. The discarded classification of Sloop would be revised, but applied to a whole new breed of warship, later versions of Jane's would simply classify them as "Old Sloops."

The era of big gun fleets, highly mobile, and the submarine and aircraft seemed to have eclipsed the sleepy Gun Boat guarding the estuaries of the Empire. But they would prove their worth in the conflict to come and be the vanguard of the modern Steel Escort.

A modern take on the Bermuda Rigged Sloopbr />

Gaff Rigged Sloop, the mainsail has an additional boom to allow a squarer sail with more sail area.

HMS Jamaica, 14 Guns, a Snow Rigged Sloop.

HMS Mars, a Brig Rigged Sloop, in her day she would have been referred to as a Brig or a Sloop of War.

HMS Salamander, Ghost of the Old Empire, Steam and Sail driven paddle steamer with a wooden hull. 2 x 10" Guns and 4 x 32 Pounders.

HMS Beagle, first of the Steel Sloops, 8 guns, still deployed as broadsides despite being turret mounted.

50 Pdr 5" Naval Gun of the type fitted to Beagle Class Sloops

HMS Torch, 6 x 5" 50 Pdr Guns and 4 x 3Pdr Guns

HMS Algerine, 8 x 5" 50 Pdr Guns, 4 x 3 Pdr

The 4.7" gun mk I-IV was a replacement for the 5" 50 Pdr gun, employing metal propellant casings and fired a 45 lb shell. It is probable some ships were equipped with the lesser 4" gun firing a 25 lb shell. It is not easy to be sure as even dockyard references sometimes just state "Quick Firing Gun"

HMS Phoenix was a throw back to the earlier Iron Clad class of Sloop but she and her sister ship Algerine were completed with all steel hulls.

The Noon Day Gun in Hong Kong is a rare example of the Hotchkiss 3 Pdr Gun. A 47mm calibre light weight French made Quick Firing Breech Loader introduced into Naval Service in 1886, it was in fact the first Quick Firing Cannon used in the RN in that the propellant and warhead were a single unit which allowed for fast ammunition handling and reloading. It was a lightweight, simple weapon which was introduced on larger ships as an Anti Torpedo Boat Weapon, on capital ships it was even to be found mounted in the Fighting Tops; On Sloops it served as a short range "Junk Basher"

HMS Shearwater, seen here in her role as Colonial Gunboat, still carrying a full suit of sails.

HMS Espiegal showing her Figurehead, allegedly this ship was the last RN warship to be fitted with such a decoration. One of her 3 Pdr guns can be seen in a gun port abaft the Figurehead.

Maxim Naval Machine Gun "Pom-Pom" on an AA mount