Loch Katrine is the lake in the title of Sir Walter Scott's The Lady of the Lake. It is a freshwater loch roughly 8 miles long by 2/3 of a mile wide, running the length of Strath Gartney. The loch is owned by Scottish Water and is the primary water reservoir for much of the city of Glasgow and the surrounding area.
Because of the danger of pollution to the drinking water of Glasgow, oil-fired vessels are not permitted to sail the waters of Loch Katrine. Instead a biodiesel fueled, steam-powered boat named the SS Sir Walter Scott (
Link Wikipedia) offers local tourist transport between Trossachs Pier and Stronachlachar during summer
Link .
Built at Dumbarton in 1899, SS Sir Walter Scott has provided pleasure cruises and a ferry service on Loch Katrine for more than a century, and is the only surviving screw steamer in regular passenger service in Scotland. She is named after the writer Walter Scott, who set his 1810 poem Lady of the Lake, and his novel Rob Roy of 1818 around Loch Katrine.
SS Sir Walter Scott is seen here at Trossachs Pier. Snow-capped Ben A'an in the background.