CGS Petrel

CGS Petrel was a small Canadian Government Ship that patrolled the upper Great Lakes, from 1892 to 1904. Her main duties included fishery patrol. On August 12, 1903, the Petrel fired upon an American fishing vessel, Silver Spray, that appeared to be fishing in Canadian waters, off Long Point, in Lake Erie. A number of shots hit Silver Spray, and one American crew member was injured. The American Silver Spray evaded capture. Her captain would later claim she wasn't fishing in Canadian waters, that some of her nets had come adrift, and had drifted into Canadian waters.

The incident is said to have triggered Canada and the USA signing the Boundary Waters Treaty of 1909.