* U-boats that fired torpedo or used the deck gun

In the night there are several attacks : first U-659 damages one tanker and U-608 misses, a few hours later U-404 and U-218 damage each a Norwegian tanker, U-92 and U-594 miss. U-584 finishes off the tanker previously damaged by U-659.

During the next day, U-96 sinks with gunfire a Portuguese trawler in the vicinity of the convoy.

In the night of 11 to 12 sept, the U-boats press home their attacks : U-584 sinks one ship, U-211 torpedoes 2 ships both later finished off by U-608, U-380 misses, U-404 damages a tanker and U-92 misses the destroyer Ottawa. The escorts damages U-659 who must return to France and manages to beat off all attacks during day of sept 12th. Again in darkness of the night, the U-boats come up again but only U-407 and U-594 fire their torpedoes and both miss.

On daylight of Sept 13, U-594 sinks a straggler but now air escort is available from Newfoundland and aircraft drive away the U-boats from the convoy. In the night, the escort is reinforced by the RN destroyer Witch and the USN Annapolis. U-91 however sinks Ottawa, also U-411 misses a corvette and U-92 misses the convoy. Finally the operation is broken of because of the vicinity of Newfoundland with its air bases.

All U-boats deployed fired their torpedoes. The U-boat commanders were surprised by the inexperience of the Canadian escort, who fire to no good use "Snowflake rockets" illuminating the sky, trying to surprise U-boats on the surface. Since the escort lacks radar and other modern equipment, they are forced to rely on the outlooks to make sightings, but once the Snowflake flares extinct, the outlooks remain blinded by the light and can't see a thing in the darkness. The only effect of the Snowflakes is that they illuminate the convoy from miles away to the U-boats, making it easy to keep contact.

Some 47 convoys on route ON were hit by U-boats in the war.
Read more about them.