Historic ships come in all sorts of guises, from the heady days of sail to the more sedate steamships of yesteryear, such as SS Shieldhall.

SS Shieldhall sailing past Hurst Castle © Martin Perry

During the summer months, you may be lucky to spot the graceful lines of SS Shieldhall on one of her cruises down the Solent, perhaps to Hurst Castle and the Needles.

Don’t be fooled, though. The 268ft ship’s original purpose was far from glamorous, albeit all too necessary: to transport (treated) sewage from Glasgow to the sea. The third in the city’s ‘sludge fleet’, which dated back to the beginning of the century, she plied this route for 21 years.

At the same time, in common with her sister ships, the Shieldhall played an entirely different role. While sludge filled the space below decks, up on board there was a holiday atmosphere, with disadvantaged families and wounded or disabled ex-service personnel enjoying day trips ‘doon the watter’. This explains the large saloon, which could accommodate up to 80 passengers.

The Shieldhall was launched on the River Clyde in 1955. With a riveted and welded hull, a traditional wheelhouse and two big oil-fired boilers to power her two steam engines, she was typical of the design of steamships of the 1920s. Yet with the increasing dominance of diesel engines, her mechanics had long since been superseded.

Although it was operating costs that triggered the retirement of the Shieldhall from Glasgow in 1976, the tradition of sludge boats along the Clyde continued until 1998, when dumping sewage at sea was banned, and the last of the sludge boats made its final journey downriver.

The Shieldhall, however, soon found herself moved southwards to Southampton, where she continued to transport sludge during the early 1980s. When that, too, came to a halt the idea of a preservation society was formed and the ship was bought from Southern Water for her scrap value – £20,000. A little over 30 years after her launch, the former sludge boat was to find herself in the spotlight.

Now Britain’s largest working steamship, and part of the National Historic Fleet, the Shieldhall is run and maintained by a largely volunteer team under the auspices of the Steamship Shieldhall Charity (www.ss-shieldhall.co.uk/bookings).  As well as regular Solent cruises from her Southampton dock, she has been known to attend the International Festivals of the Sea in both Bristol and Portsmouth, the Dordrecht Steam Festival in Holland and the Bournemouth Air Show.

On board you can take in the craftsmanship of the teak decks, enjoy snacks and drinks in the saloon, visit the bridge with its gleaming brass, and explore both the engine room and the boiler room – with never a whiff of the past to haunt you. Whatever your interest, it’s a beguiling prospect.