Archie to SAM: A Short Operational History of Ground-Based Air ...

ANTIAIRCRAFT DEFENSE THROUGH WORLD WAR II
Watson-Watt, the eminent scientist and developer of radar, independently
came up with the same concept, giving it even
more weight. 29
The plan had a number of dangers. First, there was the
question of effectiveness. Would the new concept actually improve
the defenses? A split zone would inhibit the fighter pilots,
who claimed 883 of the 1,192 V-1 kills as of 13 July. Second,
how long would such a redeployment, entailing hundreds
of heavy guns, thousands of personnel, and tens of thousands
of tons of supplies and equipment, take? What would happen
to the defenses in the meantime? Finally, how long would it
take to get a clear decision on this proposal? With each passing
day, redeployment became increasingly difficult as more of
the mobile guns were fitted with Pile mattresses and more
guns were added to the gun belt. 30
On 13 July, Hill made the decision to create an all-gun belt
on the coast. This bold, quick exercise of authority was remarkable,
as was the speed with which the decision was implemented.
By 17 July, the heavy guns, radar, and supporting
equipment and supplies were in place, followed in two days by
the light guns. This action, which involved the movement of
23,000 people and about 60,000 tons of supplies, was no
small feat (fig. 11). The British deployed the guns on the coast
between Dover and Beachy Head, creating a zone extending
10,000 yards over the water and 5,000 yards inland. Aircraft
were restricted to altitudes above 8,000 feet in this area, but
the fighter pilots were free to roam over the English Channel
and over England between the gun belt and the balloon line. 31
Although the redeployment and separation of the aircraft
and guns was a major factor in the increased effectiveness of
the defenses, there were other factors as well. The number of
heavy guns in the coastal belt increased from 376 on 1 July to
416 on 23 July; to 512 on 30 July; and to 592 on 7 August. In
addition, there were 892 40 mm guns and 504 20 mm guns
plus 254 rocket tubes. The addition of new American radar
(SCR-584) and predictors for the British 3.7-inch guns and the
American 90 mm guns also improved the defenses. 32 Another
major technical improvement was the use of proximity fuzes
that detonated at a preset distance from the target. The new
17