PQ 18 included a CAM ship even though it already had an escort carrier, adding a last-ditch fighter to the convoy's defense. A properly compatible CAM fighter might even recover aboard the escort carrier, while MAC ships offered a more sustainable intermediate layer. Each system covered a different failure case, from a reusable carrier air group to a single emergency catapult launch. The combination shows that convoy air defense developed as a layered network rather than one ideal ship type replacing every earlier expedient.
Notable Point · 2:04:54-2:08:24
Layering escort carriers, MAC ships, and CAM ships
Convoys could combine reusable carrier aircraft with emergency catapult fighters so one aviation system backed up another.