Operation BB sent 53 destroyers and destroyer leaders, including Parker and Grenville, together with 17 submarines on a wide search for German U-boats. The sweep covered the North Sea and areas around Orkney, Shetland and the Western Approaches. It produced about 60 reported sightings and 12 attacks. No German submarine was believed sunk or damaged. The convoy-escort argument draws on that poor return: escorting merchant ships offers better opportunities to find and engage submarines than broad offensive sweeps.
Notable Point · 32:55-33:54
Operation BB and the limits of submarine hunts
Operation BB's large submarine hunt produced 12 attacks without a believed sinking, supporting the case for convoy escort.