Built in Renfrew in 1955 and used by Glasgow Corporation to take treated sludge to dumping grounds near the Firth of Clyde, she went on to perform a similar task for Southern Water between 1980-1985.
Here she transported sludge from Marchwood, Millbrook and Woolston to an area off the Isle of Wight, before being withdrawn from service because of rising fuel costs.
Shieldhall was bought by the Solent Steam Packet charity about 35 years ago, which recognised the heritage value of the vessel and has continued to operate her to this day.
A massive funding shortfall caused her to be in danger of being scrapped in 2010, but the generosity of the public saved her in spite of the massive funding shortfall.
In April 2013, the Heritage Lottery Fund (HLF) announced that they would be granting a grant of £1.4 million for the necessary hull repairs to meet modern regulations, the improvement of passenger facilities and the interpretation of the ship.
More grants were made in 2019 and 2020.