On 28 September she sighted a five ship convoy.

Ultimately 13 vessels of the 16 ship convoy were captured and taken to Gibraltar.

Both sides faced the problem of how to keep their forces supplied, primarily with ship convoys, and how best to disrupt the other side's convoys.

On 28 January she contacted a three ship convoy with four escorts off Kokuzan To.

Sackville's attacks had played a key role in allowing the 41 ship convoy to escape with the loss of only two ships.

By then the greatest threat to the Allied war effort came from attacks on their ship convoys in the North Atlantic.

The morning of 20 October the submarine found still another six ship convoy, and after evading one of the escorts delivered a six-torpedo attack.

The Greek army at Akragas was kept supplied by huge ship convoys carrying provisions from Syracuse.

The slow 43 ship convoy was attacked by U-boats between late 4 May and early 6 May.

In response, the United Kingdom closed the port, but it could not prevent local French from providing information on the passing ship convoys.