'Campobasso' was an Italian convoy from the island base of Pantelleria to Tunis involved in a naval action off Cap Bon (3/4 May 1943).
The action involved a British naval force and an Italian torpedo boats escorting the 3,566-ton transport Campobasso, and was fought in the last stages of the major Allied air and sea effort to prevent supplies flowing to and men being evacuated from the terminal Axis lodgement in North Africa, and thereby facilitating the isolation and final defeat of Generaloberst Hans-Jürgen von Arnim’s Heeresgruppe 'Afrika'. The action was thus part of the daily aerial, naval and submarine campaign mounted by the Allies against Axis forces, in the spring of 1943, in order to achieve a complete naval and air supremacy around North Africa and Sicily.
By April 1943, Axis merchant ship losses (3.3 ship per day on average) had reached an almost insupportable level, and while the Axis supply route was comparatively short between Sicily and North Africa, Allied air and naval superiority had by this time made the assembly and passage of large convoys impossible. In combination with an acute and worsening fuel shortage, this persuaded the Italians to make use of fast destroyers and/or torpedo boats to escort small numbers of cargo ships. However, the convoys could average only 8 to 10 kt as the Italians had already lost virtually all of their higher-speed merchant shipping in their efforts to keep reinforcements, weapons and supplies flowing to the Axis forces involved in the Western Desert campaign.
One of these small convoys led to the so-called Battle of the Campobasso Convoy, which was a naval engagement between three British destroyers and an Italian torpedo boat off which took place off Cap Bon, the north-eastern tip of Axis-held Tunisia, in the Mediterranean sea.
As the North African campaign was nearing its end, the destroyers Petard, Paladin and Nubian were patrolling the waters off Cap Bon under the command of Commander D. Holland-Martin. On the night of 29/30 April the destroyers moved to the north to make a sweep along the south coast of Sicily and sank a 2,000-ton merchant ship escorted by German S-boote, and themselves suffered neither damage nor casualties.
A few days later the destroyers, primed by intelligence derived from the interception and decryption of Axis radio signals, were waiting off Cap Bon to intercept a small Italian convoy. This was centred on the 3,566-ton Campobasso, which had departed Pantelleria carrying bombs, land mines, motor transport and other vital supplies to the beleaguered axis force in Tunisia. The merchant vessel was escorted by the torpedo boat Perseo, which had joined it soon after departing Pantelleria.
On the night of 3/4 May radar on the British destroyers located the two ships as they headed toward the Tunisian coast. Using the German Metox radar warning receiver, Capitano di Fregata Saverio Marotta’s Perseo detected the radar emissions of the British destroyers and warned the Italian high command that the convoy had been located.
All three British destroyers, each of them carrying the main armament of four single 4-in (101.6-mm) guns, attacked Campobasso, which was hit by 'pom-pom' light fire as well as 4-in (101.6-mm) shells. Hit many times, Campobasso was soon on fire, within 30 minutes large explosions indicated that her cargo of ammunition and bombs had started to detonate. The merchant vessel sank soon after this, but Perseo responded with her three 100-mm (3.94-in) guns and launched 450-mm (17.7-in) torpedoes, but to little effect. The British destroyers then found the range and started to hit Perseo, which was soon set on fire and then exploded, sinking within sight of the last Axis stronghold in North Africa.
An Italian hospital ship was intercepted and escorted by the British to the area of the sinkings the next day to pick up survivors.
At dusk on 8 May, as part of 'Retribution', Paladin, Jervis and Nubian bombarded Kelibia, the most easterly point of the Cap Bon peninsula, and repeated this bombardment at dawn on the following day until the last Axis forces in Tunisia surrendered.