The concept was straightforward: launch rockets ahead of an attacker and suspend explosive hazards in its path. A warship and its attacker were both moving, so the ship could leave its own protective pattern while the aircraft turned around it. Proposed fits included four projectors apiece on five battleships, pairs on six cruisers, and one on the monitor HMS Erebus. Even that distribution could create only several visible sections of temporary minefield, rather than an enclosing shield. A visually impressive barrage was therefore a poor substitute for a reliable interception system.
Notable Point · 22:39-24:24
Why a ship could outrun its own aerial minefield
The Unrotated Projectile could put parachute-borne charges into the air, but its defensive pattern was ill suited to a moving ship and an evading aircraft.