Sir Walter Scott steamer on Loch Katrine

SS Sir Walter Scott is a small steamship that has provided pleasure cruises and a ferry service on Loch Katrine in the scenic Trossachs of Scotland for more than a century, and is the only surviving screw steamer in regular passenger service in Scotland. It is named after the writer Walter Scott, who set his 1810 poem Lady of the Lake, and his 1818 novel Rob Roy around Loch Katrine.

In 1859 Loch Katrine became Glasgow's main water supply, connected by aqueducts and tunnels to the city more than 30 miles (48 km) away through a hilly landscape. The Trossachs became very popular in the Victorian era, and there were early steamship services on the loch. The Loch is surrounded by wooded mountains, and has romantic historical connections including the birthplace of the outlaw Rob Roy MacGregor. Queen Victoria had a holiday house built overlooking the loch.

William Denny and Brothers built Sir Walter Scott as a "knock-down" ship; that is, it was assembled with bolts and nuts at Denny's shipyard at Dumbarton on the River Leven, the pieces numbered and dismantled again, transported in pieces by barge up Loch Lomond and overland by horse-drawn cart to Stronachlachar pier on Loch Katrine and there rebuilt with rivets and launched. Denny's assembled Sir Walter Scott at their yard in 1899 and completed its reassembly and launch on the loch in 1900.

All ships in the UK must record a measured mile for seaworthiness. Sir Walter Scott completed its measured mile on the Firth of Clyde when bolted together, before being disassembled, transported to Loch Katrine and riveted together again.

Its original cost was £4,269, which included a delivery charge of £2,028