CANTAT-1 was the first Canadian transatlantic telephone cable, between Hampden, Newfoundland and eventually Grosses-Roches, Quebec and Oban, United Kingdom, which followed on from the success of TAT-1. It was conceived and approved as stage one of a proposed commonwealth round the world cable and was done at a cost of $8,500,000. The system was jointly owned by Cable & Wireless and the Canadian Overseas Telecommunication Corporation (COTC).
The system, involving the first commercial use of a new lightweight deep sea cable with a weight in water of about one-fifth that of armored deep sea cable, was laid in two phases. The first, CANTAT A, was the ocean section laid by HMTS Monarch with the U.K. shore end laid by HMTS Ariel and the Canadian end laid by the U.S. Army CS Albert J. Myer. The second phase, linked by overland cable from Hampden to Corner Brook, Newfoundland, was the segment laid by HMTS CS Alert with both shore ends laid by CS Hadsund.