FOR generations of Scots sailing "doon the watter", it has established its place in the cultural history of the Clyde.

Now the PS Waverley paddle steamer has been awarded a place in a pantheon of Britain’s engineering achievements as well, sitting alongside famous works such as London’s Tower Bridge, the Bletchley Park Bombe decoding machine and Brunel’s SS Great Britain.

Recognition of the 1946 vessel’s significance was formalised yesterday when it was awarded an Engineering Heritage Award by the Institution of Mechanical Engineers -- only the second time the accolade has been awarded in Scotland since it was established in 1984.

However, it carries bittersweet tidings for the vessel’s owners, who launched a fundraising appeal earlier this year amid fears that 2011 could be the last year it can afford to stay afloat, with rising fuel costs and a succession of rainy summers threatening its viability.

Professor Isobel Pollock, president elect of the Institution of Mechanical Engineers, said: “The Waverley is not just a link to the past but an example of extraordinary British engineering and craftsmanship.

“It’s testament to the great skill of the original shipbuilders, as well as the fantastic restoration work of the current owners, that after 65 years the paddle steamer is still going strong.”

The Waverley was built in Glasgow by shipbuilders A & J Inglis to replace the original PS Waverley which was sunk in 1940 as it helped to evacuate troops from Dunkirk.

For many, the core attraction of the Waverley remains its engine room, which has drawn generations of naval and engineering enthusiasts below deck to soak up the rich, oily aroma and characteristic wheezing sounds of the gigantic, 8ft-long piston rods driving the 18ft paddle wheels.

Though hopelessly inefficient by today’s standards, the diagonal triple expansion engine that powers the ship was a work of advanced engineering in 1940s and represented an enormous advance on the single expansion steam engines of the first paddle steamers a century earlier.

Ken Henderson, chief engineer of the Waverley, who has worked aboard the ship for 21 years, said: “It is one of the very few steam engines of that size that you can actually go and view on a daily basis which is still earning its living.

“There are plenty pumping stations and preserved engines in other historic places which may be fired up once a month. But I can’t think of anything else that is running on a daily basis, six months a year.”

With a theoretical top speed of 18 knots -- physically possible, though it would burn around a tonne-and-a-half of fuel per hour -- the Waverley’s engineering importance and its role as the last sea-going vessel of its type, is more than worthy of celebration, Mr Henderson said.

The institution has granted previous Engineering Heritage Awards to works as diverse as Robert Stephenson’s works, which produced the Locomotion and Rocket steam trains after opening in 1823; and the Channel Tunnel. Its only other Scottish entry is the house of renowned mechanical engineer Theo Williamson in Edinburgh.

Kathleen O’Neill, general manager of operating company Waverley Excursions, said there was still “some way to go” with a fundraising appeal aimed at raising £250,000 by the end of the year and said that, to date, most contributions had come from private donors in England and Wales.

“Unfortunately, we have been hit by the poor weather in July but we will have to wait until the end of the season to see how well we’ve done,” she said.