A funding crisis is threatening the future of a British-built vessel which is the world's last surviving sea-going paddle steamer.
There are fears that unless more money can be raised, the current sailing season of the 1947-built Waverley Paddle Steamer, at present operating on the River Thames, will be its last.
Around £200,000 has been raised for Waverley, which was built on the River Clyde in Scotland, but a further £150,000 is needed for a vessel which takes many thousands of passengers on day trips across the UK each year.
More than 20 MSPs (Scottish Parliament members) are backing the bid to save the Waverley, which is operated by the charity, the Waverley Steam Navigation Company.
With its fleet mate, the Classic Cruise Ship Balmoral, Waverley contributes around £4.8 million each year to the UK economy.
Hikes in fuel prices and some poor summers have contributed to the vessels' funding crisis.
Nick James, chairman of Waverley Steam Navigation Company, said: "We are looking forward to Waverley's supporters and people who have not sailed with us before stepping aboard and enjoying the sailings on the Thames for the next two weeks.
"Passenger numbers are up, which is fantastic. However, a number of south coast sailings had to be cancelled due to the recent exceptional weather, so it is now critical that as many people as possible come aboard for a cruise or make donations in order to ensure this wonderful historic ship can sail again next year."
Waverley is the last ship of a line going back to 1812 and, although built half-way through the 20th century, is a unique working example of 19th century technology.
Sold in 1974 by shipping company Caledonian MacBrayne to the Paddle Steamer Preservation Society, Waverley's strongest operational areas are Glasgow and the Clyde coast; Bristol, Cardiff and the Bristol Channel; and London and the Thames Estuary.
The ship had multi-million pound rebuilds in 2000 and 2003, funded largely by the Heritage Lottery Fund.