One of the last frigates built that shared a design with the ships of the Nelson-era Navy, HMS Unicorn included a number of innovations used in subsequent classes of warships. Although it never saw active service, it was used as a training facility by the Reserve forces and today is one of only a few ships surviving from the period.



Initial Build


HMS Unicorn was laid down in February 1822 at Number 3 slip in the Royal Dockyard of Chatham and was launched on 30 March 1824. A Leda class frigate armed with 46 guns, she was designed to be fast and manoeuvrable but also large enough to support significant fire-power. Her design included a number of modifications from the previous ships of the class; in particular Unicorn was one of the first vessels to be fitted with iron diagonal strengthening straps knwon as 'riders'. These counter-acted the general loosening of a wooden ship during protracted periods at sea. Such modifications would later herald ships large enough to support engines.

Weapon Fit


Unicorn was classed as a Fifth Rate Warship (see below) and the design benefited from having its main armament on a single Gun Deck. This replaced the earlier Roebuck class that had their main weapons split over two decks; the result being the lower tier of weapons could only be utilised in calm seas. Instead the 28 heavy guns on Unicorn's single deck (14 on each side), could be operated up to moderate sea states.


The main weapons on the ship were 18 pounder long guns based on a version designed by Sir Thomas Blomefield. They had a range of over one mile and a huge penetrative power capable of punching through almost a metre of solid oak at closer ranges. The remainder of Unicorn's armament, predominantly consisting of shorter range 32 pounder Carronades, was installed on the Upper Deck.


Gun Deck (Main Deck)


As noted above the main deck supported the primary armament of the ship but also included, at the stern, the Captain's Cabin. This offered the Commanding Officer significant space and would have been well furnished albeit the cabin was shared with four of the heavy guns. A fitted shower was probably included from the earliest build of the ship. Unlike earlier vessels, which boasted large windows and a square design to the room, Unicorn was built with a rounded stern. This was designed to be more robust against enemy shot and also allowed heavy guns to be angled out providing vital coverage of the ship's quarters; heretofore a significant weakness.


Lower Deck (Accommodation Deck)


The Lower Deck provided the accommodation for the Ship's Company. Officers were in the Wardroom at the rear of the deck in individual cabins that surrounded the main table where they worked and ate. The cabins were modular and were dismantled when the ship secured for action during which the Wardroom was re-designated as a Medical Centre (comparable with a modern warship).


In front of the Wardroom were the Warrant Officers and Senior Rates cabins. Here key individuals - such as the Master Gunner, Carpenter and Boatswain - were accommodated. It was also home to Midshipmen (trainee Officers).


The forward half of the deck was the open plan main Mess Deck; the accommodation space for the Unicorn's approximately 230 strong crew of Junior Ratings (who would have been augmented by up to 50 Royal Marines). The sailors slept in hammocks which were secured during the day and replaced with temporary wooden tables for dining.


Orlop Deck and Hold


Below the Accommodation Deck was the Orlop Deck and beneath that the Hold. Both were used for storing provisions and equipment required to sustain the ship for as long as six months at sea. The Orlop Deck also supported two Magazines used for storing Gunpowder; these were fitted out with a copper lining to prevent rats biting into the prepared powder cartridges whilst a double glazed window allowed an external lantern to provide light without the risk of explosion. The Orlop Deck, which is just below the waterline, was built with a walkway running along the Ship's hull on both sides to enable the Carpenter to respond quickly to any damage in this crucial area.




Unicorn was never destined to see active service. Following the defeat of Napoleon at the Battle of Waterloo (1815), there was peace between Britain, France and the United States of America. Unicorn, completed in 1824, was immediately placed in reserve. Her masts and rigging were never added whilst a roof was built over the hulk. This was standard practice to preserve ships in peacetime as there was little benefit in having the main hull, which took two years to build, exposed to the elements especially as cutbacks in Royal Navy personnel meant a reduction in the care and maintenance of the platform. Should the ship have been needed, it would have taken as little as two weeks to fully rig it for sea.


Obsolescence and Training Role


Unicorn remained in reserve until 1857 when she was sent to Woolwich Arsenal to act as a powder magazine. In April 1862 she was returned to the reserve and laid up in Sheerness. This was a time of significant change for the Royal Navy - in 1852 Napoleon III had become Emperor of France and prompted an arms race with Britain. This included development of the first Ironclad warship ('La Gloire'; the Glory) which outclassed anything in the Royal Navy and rendered small, wooden sailing ships such as Unicorn obsolete. Britain started rebuilding the Navy commencing with HMS Warrior but the changes guaranteed that Unicorn would never be activated in her primary role. She remained in a sound condition however so in 1871 the Navy prepared her for a training role and was originally destined for Belfast. However it was never sent and in October the same year was offered to Rochester Council to be used as a Cholera ship. This offer was declined and instead, in November 1873, Unicorn was towed north to Dundee (by HM Paddle Sloop Salamander) to act as a training ship for the Royal Navy Reserve. Berthed in the Earl Grey Dock, the ship was fitted out with two small signal masts.


Upon the creation of the Royal Navy Volunteer Reserve in 1906, Unicorn was lent to the Clyde division of the new organisation (although the hull remained in Dundee). During both World Wars she acted also as the Headquarters facility for the Senior Naval Officer in Dundee. Unsurprisingly this led to substantial modifications internally as the Gun Deck was converted into Offices and Mess Decks whilst other training facilities were also installed; Unicorn must have been one of the few Nelson-era ships to have ever been fitted with a radar! A wide variety of armaments were also added over the years including a large breech loading pivot gun similar to that seen in contemporary land fortifications. Despite her continued use however, the large ship building programme of World War II led to the name Unicorn being re-allocated. Instead a new aircraft carrier took the title as the First Lord of the Admiralty - James Stanhope, Earl of Chesterfield - was unaware of the old frigate. Accordingly the ship changed its name to Unicorn II in 1939 and then HMS Cressy in 1941. It reverted to the original name in 1959 after the aircraft carrier had been decommissioned and scrapped.




Despite surviving two World Wars, Unicorn came close to being broken up when the Earl Grey Dock, where it was berthed, was decommissioned in 1961 as part of the Tay Road Bridge construction. After lobbying by a Captain Anderson, a former Commanding Officer of the ship, it won a reprieve and in 1967 the Unicorn Preservation Society was created to secure the platform a long term future. After extensive restoration to its original nineteenth century configuration, it was opened to the public in 1976. Work continues but we must be hugely grateful to this dedicated team who preserved such a rare asset; in particular the roof, once a common form of protecting warships in upkeep/reserve and also used on training hulks such as HMS Britannia at Dartmouth, is unique.




Cohn, R and Russell, J (2012). HMS Unicorn (1824). VSD.

Davery, J (2015). In Nelson's Wake: the Navy and the Napoleonic Wars. Yale University Press.

Gardiner, R (2000). Frigates of the Napoleonic Wars. Chatham Publishing.

Grove, E (2005). The Royal Navy since 1815. Palgrave Macmillan.

Lambert, A (2003). Trincomalee: The Last of Nelson’s Frigates. Chatham Publishing.

Lavery, B (2013). Nelson's Navy: the Ships, Men and Organisation 1793-1815. Conway.

Lyon, D (1993). The Sailing Navy List. Conway Maritime Press.

Roderick, S (1982). Welcome Aboard the Frigate Unicorn.

Roger, N.A.M (1998). The Wooden World: Anatomy of the Georgian Navy. Fontana Press.

Roger, N.A.M (2006). Command of the Ocean: A Naval History of Britain 1649-1815. Penguin.


Ships of the Line


Although it had been developing since Tudor times, a formal rating system for Ships of the Royal Navy was detailed by Samuel Pepys, Secretary to the Admiralty in 1677. His aim was to standardise classification and with it the number of guns and men required enabling the cost of construction, operation and logistics to be effectively determined. It also enabled calculation of which vessels could be employed as 'Ships of the Line', namely how many were available to form part of the battle line in a major sea battle. The scheme was key in the development of the Royal Navy as a world power and was updated on a number of occasions in the eighteenth and nineteenth centuries.


First Rate

The largest and most powerful ships in the Royal Navy, these had three tiers of guns (at least two Gun Decks and weapons on the Upper Deck); between 100 and 120 guns in total. These were 'Ships of the Line' and HMS Victory is a surviving example. The reforms to Pepys' rating system in 1817 led to all three deck warships being classified as First Rate.


Second Rate

These were also 'Ships of the Line' but fitted with 90 guns or fewer (this was later increased to 98). These could be configured in two or three tiers although the latter were reclassified solely as First Rate in 1817.


Third Rate

These were the smallest 'Ships of the Line' and fitted with 80 guns or fewer. Normal configurations were 64, 70, 74 or 80 guns across two decks.


Fourth Rate

Vessels with two Gun Decks with either 50 or 60 guns. By the mid-eighteenth century these had been deemed too small for sea battles and therefore were no longer Ships of the Line. By the time Unicorn was built Fourth Rate ships had largely been superseded by the more versatile Fifth Rate frigates although some continued to be used in outposts of the British Empire.


Fifth Rate (Frigates)

Designed to be fast and manoeuvrable but also large enough to support significant fire-power (configurations were 32, 36, 38, 40 or 44 guns). All their main weapons were on a single Gun Deck (although additional weapons were also on the Upper Deck). The ships were frequently deployed as advanced scouts for the main fleet or deployed as singleton units. In the modern Royal Navy a frigate has a similar role as a general purpose platform although since World War II increased focus has been on Anti-Submarine Warfare.


Sixth Rate (Small Frigates and Corvettes)

Smaller ships of either 20, 24 or 28 gun configuration including small frigates and corvettes. These ships were predominantly used for blockade and convoy escort duties as well as hunting down enemy privateers.



Not part of the rating system but nevertheless a type of warship that formed a major part of the Royal Navy during the Napoleonic wars. Fitted with fewer than 20 guns.


What's There?

HMS Unicorn is the hulk of a Nelson-era Frigate that has been painstaking preserved by the charity that looks after it. All decks are accessible allowing the visitor almost unrestricted access.

HMS Unicorn. The Leda class was based on a captured French frigate, the Hébé. This had been seized in 1782 and the design was copied by the Royal Navy starting with HMS Leda in 1800. The class included forty-six vessels although, due to peace with France, the final ships in the class were never completed. One of them, HMS Trincomalee, is on display in Hartlepool. Famous ships of the class were HMS Shannon, which defeated the USS Chesapeake during the 1812 war, and HMS Pomone which sank off the Needles in 1811.

Colour Scheme. The distinctive colour scheme of the Unicorn is a legacy of Admiral Nelson. He ordered his ships to be painted black with a yellow band at each of the Gun Ports making it easy to recognise each class of Ship. In 1817 the yellow band was changed to white.


Roof. The ship is the only known surviving example that retains its roof - a standard way of preserving vessels that were mothballed. Had Unicorn been fully fitted out for sea, she would have been equipped with three masts; Foremast, Mainmast and Mizzenmast. Collectively these would have supported 1500 square metres of canvas. Over 23 miles of rigging would have been used. Note also the rounded stern to increase protection from direct fire.

Accommodation. The ship’s accommodation for all personnel, except the Commanding Officer, was on a dedicated deck. The Warrant Officer/Midshipman cabins are shown above left. Further aft was the Wardroom (right) whilst forward was the single open plan Mess Deck for the Junior Rates.

Getting There

HMS Unicorn is located within Victoria Dock in central Dundee. There are ample car parking facilities in the City Centre or pay-and-display options in immediate vicinity of the ship.

HMS Unicorn


56.461475N 2.958393W