Document Type


Degree Name

Master of Arts (MA)




Faculty of Arts

First Advisor

Barry M. Gough

Advisor Role

Thesis Supervisor


The Battle of the St. Lawrence is one of the least discussed engagements in Canadian naval history. The vast majority of those who have dealt with it write off the battle as simply a defeat for the Canadian war effort. On closer examination, however, it becomes clear that the Battle of the St. Lawrence and its aftermath, the closure of the St. Lawrence to shipping, are much more complex. The RCN and the RCAF accomplished much in coastal defence with very little resources, and though no U-boats were killed in the engagement, Canadian naval and air units working in combination gave the appearance of coordinated ASW to German submarine commanders. U-boats did not return to Canadian coastal waters in the following shipping season. Furthermore, Canadian defence planners took valuable lessons from the setbacks in the Gulf in 1942 and devised more aggressive doctrines for escort work and air patrols. The most important contribution of this work is the analysis of the decision to close the St. Lawrence. Whereas most historians contend that the Canadian government closed down a vital maritime artery in a panicked response to losses in the St. Lawrence, it is shown that the decision was the culmination of a carefully drafted policy which had been considered for several years. The policy incorporated the preferences of both Canadian defence planners and the British Ministry of War Transport. The decision to close the St. Lawrence did not have its intended effect, since shipping resumed in the Gulf of St. Lawrence with some restrictions in early 1943. The impact of the Battle of the St. Lawrence on the war effort, conversely to what other historians have argued, was in fact negligible.

Convocation Year


Convocation Season