We used to make things in this country #142, Ottawa River Alligators

Robert Legget, Ottawa Waterway, Gateway to a Continent, University of Toronto Press 1975.

With specialized jobs comes specialized tools and when the Ottawa river lumbering trade required a way to efficiently control the floating of logs and booms downriver, the Alligator was the result. Previously booms of logs had been moved manually- by a capstan mounted on a raft that was rowed to location and anchored in place. Using men or a horse the cable was laboriously wound up, warping the boom up to the raft and the whole process repeated as necessary.
The Alligator was a steam-powered development, made by a Simcoe, Ontario company, West and Peachey, after they travelled north to watch the process.  Basically it was a simple steam powered flat bottomed sidewheeler scow (later propeller-driven), with a large power winch located in the bow.  The hull incorporated metalclad skids which allowed the tug to portage itself across dry ground or log booms when necessary.
 Between 1889 and the 1930s about two hundred were built for use in logging operations across eastern Canada and the northern US. They were replaced by gasoline powered warping tugs built by the Russel Brothers Company in Owen Sound, Ontario.

More reading: http://www.mcelroy.ca/notes/alligators_algonquin.html

http://www.dundurn.com/books/alligators_north