This year's Glasgow TMSA trip on the Clyde Canal starts from Baird's Brae at 1pm on Sunday 29th July, and lasts 4 hours. Full details here: http://www.tmsa.org.uk/scottish-music-event.asp?e=2785&b=7

Linlithgow Folk Festival also usually have musical cruises on the Friday night of festival weekend: their brochure for this year's festival will be out in early July. The relevant Friday is September 8th.