The Atlantic was both an ally and a physical danger because escorts fought the ocean while trying to distinguish submarines from wrecks and bottom contacts. In the 1944 example, HMS Lavender obtained an ASDIC contact that HMS Flint Castle could not confirm. A second contact drew Hedgehog attacks and explosions that may have come from the seabed. The ships continued to prosecute doubtful returns because an attack could drive a real submarine away even without producing a confirmed kill. Persistent prosecution also denied U-boats a reliable tactic of hiding beside wrecks or ambiguous sonar returns. Once the threat was suppressed, the escorts could catch up with the convoy, returning the action to the central mission of protecting its passage.
Chapter · 18:17-20:02
Why escorts prosecuted uncertain contacts
A 1944 action illustrates why escorts continued to attack doubtful sonar contacts: driving submarines away was itself a convoy-protection result.