The attempt of the U.S.S. Manhattan, a prototype of future Arctic supertankers, to force its way through the ice-clogged Northwest Passage in 1969, raised anxieties in Canada. The ostensible purpose of the voyage was to demonstrate the practicability of such ships in seeking the newly discovered oil deposits off the north shore of Alaska. Ottawa regarded the voyage as a foreign challenge to Canadian claims of exclusive jurisdiction in those waters.
The voyage was only a partial success. Despite her powerful engines, the Manhattan was frequently caught in the ice and had to be helped by Canadian icebreakers like the John A. Macdonald shown here. The John A. Macdonald's presence and aid demonstrated that Canada still "ruled the waves" in northern waters. For its part, the United States developed plans for powerful tankers and for ice breakers of its own which would need no Canadian assistance at all.
