Piercing the Fog - Air Force Historical Studies Office

Building an Air Intelligence Organization
located. The initial Allied attacks compelled Kesselring to use convoys heavily
protected by air cover and Siebel ferries which had been adapted to carry
batteries of AA artillery. Just as Allied aircrews began to master air-to-sea
operations, the Axis benefited from two developments that temporarily swung
the advantage to their side: German occupation of Vichy France provided
450,000 additional tons of shipping, including desperately needed oil tankers,
and Rommel’s withdrawal from Tripolitania allowed the Axis to close the
vulnerable run to Tripoli, which freed bottoms for the shorter, safer Sicily-to-
Tunisia 0peration.2~’
The B-25s of NASAF initiated the aerial portion of the antishipping
campaign on January 11, 1943, followed by the B-26s several days later. The
first sinking did not occur until January 20. After several successful attacks, the
medium bombers went from January 29 to February 9 without sinking an enemy
merchant vessel. Another dry spell lasted from February 10th to 2l~t.’~’
Improvements in the weather and an increasing skill at correlating intelligence
and operational capability produced marked improvements. In March, the Axis
stepped up the number of sailings, but the Allies destroyed, in port or at sea, 50
percent of these ships, this in contrast to the less than 20 percent rate of the
previous month. American air forces were not solely responsible for these
results; the extensive naval activity included two-thirds of the Royal Navy’s
submarines.252
Incorporating supply specialists into the targeting process allowed Doolittle
to focus more specifically on critical cargoes, thus enhancing overall results.
Here ULTRA was at its best. The sinking of the tanker Thorsheirner in late
February, based on ULTRA guidance, accounted for 70 percent of the known
Axis fuel shipment to Tunisia that month. The next month, again thanks to
ULTRA, the Axis delivered only about one-third of the fuel requirements to the
energy-starved German and Italian ground and air forces.253
While the medium bombers took to sea, B-17s and B-24s concentrated on
the ports, attacking ships and destroying unloading equipment and storage
facilities. Through January and February, the focus of these attacks was Tunis
and Bizerta. By mid-March, having begun to drive the Axis to shallower vessels
at smaller ports and eventually to over-the-beach operations, NASAF reached
into Sicily and Sardinia. In the meantime, B-24s of the Ninth Air Force
operating from Tripoli bombed targets in Italy and Sicily, including ferry slips
and equipment, submarine bases, and port facilities.254 Apparently tipped off by
an RAF reconnaissance report, Ninth launched three attacks against Catania.
Demonstrating the relative and at times quixotic nature of precision bombing,
the attackers severely damaged port facilities, but they failed to sink the tanker
that was their principal target.255
In addition to their interdiction role against enemy shipping, Allied air
forces continued to operate against enemy air capabilities with both the NASAF
and the NATAF. Using ULTRA as well as visual means and photoreconnais-
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