As far as the size of these vessels is concerned, it has been found that all are loaded with more than a hundred tonnes, the limit set by the agreement. The shift from wood to steel in the middle of the last century, along with other factors, contributed to making this part of the agreement obsolete. To our knowledge, the Canadian government has not objected to the presence of naval vessels on the Great Lakes, with a load of more than one hundred tonnes, and there would be no propensity to question Canada`s maintenance of the vessels currently operating there. For many years, our Department of the Navy seems to have been the practice of deploying on the Great Lakes only « unclassified » ships that have long since survived their usefulness in terms of modern warfare and are no more than fourteen feet deep. I understand that these ships have and are of no other use than the basic training of naval reserves. Lord. Hull believed that it would be desirable to pursue this policy, which went beyond the objectives of the 1817 agreement, but which corresponded so clearly to the current temperament of public opinion. He informs the Ministry of the Navy. Although the treaty caused difficulties during the First World War, its terms were not changed. Similar problems arose before the Second World War, but Foreign Minister Cordell Hull wanted to preserve the agreement because of its historical importance. In 1939 and 1940, Canada and the United States agreed to interpret the treaty so that weapons would be installed in the Great Lakes, but would no longer be operational until ships left the lakes. In 1942, the United States, now at war and allied with Canada, successfully proposed that weapons be fully installed and tested in the lakes by the end of the war.
Following discussions in the Permanent Joint Board on Defense in 1946, Canada similarly proposed to interpret the agreement to allow the use of ships for training purposes when each country informs the other.  After carefully weighing the issue, Mr. Hull tends to think that a change to the Rush Bagot agreement would not be desirable at this stage. . . .