THOUGH its history as a shipbuilding centre has always been overshadowed by Glasgow and the Clyde, it is Dundee and the Tay that house the best museum ships in Scotland in the research ship Discovery and the early 19th-century sailing ship HMS Unicorn.

HMS Unicorn berthed at Dundee’s thriving waterfront not far from the somewhat more famous Discovery 200 years ago this week – the oldest ship still afloat in Scotland. Unicorn is one of the six oldest surviving ships in the world having been launched on March 30, 1824.

Unicorn is not the oldest ship still afloat in the UK as is sometimes erroneously claimed, as that honour belongs to HMS Trincomalee, launched in 1817 and now berthed in a dock at the National Museum of the Royal Navy at Hartlepool.

Interestingly, Trincomalee was one of the Leda-class frigates built for the Royal Navy between 1805 and 1832, as was Unicorn. They shared the same length of 150ft (45.7m) but Trincomalee was built of teak in India while Unicorn was built at Chatham and was largely made of oak.

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Unicorn did have a major difference from HMS Trincomalee, however, as Sir Robert Seppings – a brilliant designer of ships in the early days of the Industrial Revolution – gave her an elliptical stern and incorporated iron features into his innovative design. Unicorn is the only surviving example of Seppings’s stern design which has been credited with greatly advancing the architecture of wooden sailing ships at a time when Britain was building its empire.

The Unicorn’s website states that “in 1819, the House of Commons singled out the work of Seppings as having introduced many of Britain’s ‘most valuable improvements in naval architecture’”. They concluded by commenting that although his work may “have nothing of that brilliancy which forcibly excites public admiration, it will continue to confer a lasting benefit on the British nation, long after that period when the beneficial effect of victories, however splendid, shall have passed away”.

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Seppings, who rose from humble beginnings to become a surveyor of the Navy, designed many new structural improvements using iron that certainly made naval vessels stronger and longer-lasting but it also helped to preserve HMS Unicorn as she never saw action at sea, unlike HMS Trincomalee.

This was the era when the Napoleonic Wars had been won, when there was peace with the USA and other powers, and when the British Empire was growing, largely under the protection of the Royal Navy. So the Government continued to invest in new ships such as Unicorn which cost £26,000 or more than £3 million in today’s money. Unicorn looked set for a globe-trotting role asserting British might, but that was not necessary.

Instead, after her launch from Slipway No 4 at Chatham Royal Dockyard, she was immediately laid up or put “in ordinary” as it was termed back then. Ordered in 1817, HMS Unicorn was then the latest in a long line of naval vessels that carried the name – and of course, the unicorn is Scotland’s national animal so it’s appropriate that she now rests here.

Her keel was laid down in 1822, and even during the construction of the three-decked 1000-tonne frigate scheduled to have a crew of more than 300 and to carry 46 guns – including the famous carronades manufactured at the Carron Ironworks near Falkirk – it was realised that she would not see action so the Admiralty ordered that she not be fully rigged as intended.

Instead, HMS Unicorn had a superstructure built over her main deck, basically given a roof – another reason why she is in such a good state of preservation – and spent the first few years of her life in reserve waiting for a war or naval campaign that never happened.

From 1857, for five years, HMS Unicorn became a powder store for general use by the military, but her career as a possible fighting frigate was over, with iron ships and steam power rendering her redundant.

Yet her remarkable state of preservation made her ideal for conversion to a training ship and in 1873, she was towed to Dundee to begin a new career with the Royal Naval Reserves. The Unicorn’s website takes up the story: “Leaving Sheerness on November 5, 1873, HMS Unicorn was towed up the east coast of the UK by paddle sloop HMS Salamander.

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“When the ship arrived in Dundee, she was placed in her new berth against the south-western wall of the Earl Grey Dock. She remained in this spot for 89 years, only being moved in 1962 for the construction of the Tay Road Bridge.”

During that period, she had been an administrative centre during both world wars and continued as a training vessel.

It was at that point in 1962 that it looked as though Unicorn would end her days in the breaker’s yard. Instead, former captain Jack Anderson started the campaign that led to the Unicorn Preservation Society (UPS) being formed, with the late Prince Philip accepting the ship into the care of UPS in 1968.

According to National Historic Ships: “Her unexpectedly sheltered life in reserve under a roof – with no battles, sea-service or modern re-building – means she is accepted as the most original old ship in the world. The hull has only ever had minimal repairs, mainly to external planking above the waterline and some deck planking on the two highest decks, representing an estimated 8-10% of the ship’s structure measured by volume of material.”

The National Historic Ships website also tells of Unicorn’s recent history and her future: “Since 2014, UPS has been working to create a sustainable future for HMS Unicorn, which has led to the development of a major maritime project: Operation Safe Haven. HMS Unicorn is acting as a catalyst as Dundee rediscovers and celebrates its maritime past with the next stage of development of the city’s waterfront.

“Operation Safe Haven will see Unicorn moved to the East Graving Dock where conservation work will continue.”