What happened to the battle for supply lines in North Africa?

Operation "Ironclad"

The island of Madagascar is located in the western Indian Ocean, facing the African continent across the Mozambique Strait. Due to its important strategic location, the island of Madagascar, far away from the hustle and bustle of the Mediterranean battlefield, became extremely unstable. The ownership of the island was related to the supply issue of the British army's North African operations.

In order to ensure the victory of its North African operations and provide supplies for its troops in Egypt, Britain opened three communication lines: one is a shipping line for fast convoys to bypass Africa, with a total length of 1.16 More than 10,000 sea miles, winding and twisting, forming a unique battlefield scenery; the other is an air transport route through Central Africa, from Takoradi to Nigeria and French Equatorial Africa to Egypt; and the other is a route into the Mediterranean through Gibraltar , although it has a shorter range, it is only used in special circumstances due to its vulnerability to enemy attacks.

The supply base of the Axis ground forces in North Africa is in Italy. It only takes three days to deliver supplies to North Africa, saving time and effort, and can supply frontline troops in a timely and effective manner. However, Britain's main maritime transportation had to detour through the Cape of Good Hope and reach North Africa via Madagascar. Each voyage took three months. Compared with the North African Axis countries, although the voyage is far, it is safe and reliable without unnecessary losses. From the second half of April to November 1942, 337,000 soldiers arrived at various ports in the Indian Ocean from Britain, of which about 200,000 were transported to the Middle East.

Since Japan launched its offensive in the Pacific and Indian Oceans, Britain has been worried about the Axis Congress building a base in Diego-Suarez, Madagascar. Because from this base, the German or Japanese navy and air force can not only threaten India and South Africa, but also attack the British transport fleet heading to Egypt, so Britain's worries are not unreasonable.

Madagascar is a French colony, but Britain has long been skeptical of the Vichy government. Especially after France transferred French Indochina to Japan, Britain lost trust in the Vichy government. To prevent Madagascar from falling under Japanese control, the British decided to launch an amphibious assault on Madagascar and capture the port of Diego Suarez. The operation was codenamed "Ironclad Ship". The ships implementing the "ironclad" combat plan include the two aircraft carriers "Glorious" and "Invincible", the battleship "Lamiyi", 2 cruisers, 11 destroyers, a large number of minesweepers and submarine-driving speedboats, and 15 cargo ships Army transport and assault ships.

At 4:30 in the morning on May 5, 1942, the first batch of British troops began to land at Corel Bay in the northeast of Madagascar. The Vichy French garrison numbered more than 4,900, including 800 French. The British army quickly broke through its resistance, and after landing on land, they quickly occupied the only fort that could fire to the sea, and advanced eastward, capturing the city of Diego Suarez at 4 p.m. The second group of troops landed south of Ambalarata Bay and advanced towards Antsirana in the east. The leading force of the 29th Brigade was blocked 3 kilometers south of Antsirana.

At 8 pm on May 6, with the reinforcement of the 17th Brigade, the 29th Brigade launched the last assault and succeeded. At the same time, British Marines carried out a surprise landing in the rear of the French defenders.

On May 7, the French army surrendered. The British troops occupied Diego Suarez and Antsirana, with less than 400 casualties. The French navy suffered major losses, including three submarines.

Four months later, the British army landed in Madagascar again and occupied its west coast ports, Mahajanga and the capital Antananarivo. At the cost of more than 100 casualties, the British army completely controlled the island's "ironclad" operation. A complete success.

Meanwhile, the British 8th Army had contained Rommel's troops in front of the Aleman position, and in accordance with the instructions of the British Prime Minister and Cabinet, the troops were replenished and trained to meet the German attack on Aleman. attack, and go all out to prepare for the final large-scale counterattack, eliminate the effective forces of the German and Italian troops, and cooperate with the Allied landing operations in North Africa. With the danger of the Cape of Good Hope route eliminated, British reinforcements to the Middle East were rapidly strengthened, and large quantities of materials and troops were continuously transported to North Africa. Transportation lines were unimpeded, accelerating the victory of the North African war.

Seize the "throat" of North Africa

Barton in the Tunisian Campaign Malta Island is located in the center of the Mediterranean Sea. It is an intermediate stop for Allied ships traveling between Gibraltar and Alexandria. Its location is very important. . At the same time, because it is right across the route of Italy and Libya, it has become a strong fortress that can effectively attack the shipping of the Axis powers. It is called the "throat" leading to North Africa. Allied fighter jets and bombers stationed in Malta forced German and Italian transport ships to take detours, which increased the difficulty of German and Italian transport. This greatly weakened the ability of Germany and Italy to carry out transportation to North Africa, and also weakened the combat effectiveness of the front line.

As a base for the British fleet, Malta was able to threaten the Italian and German transport fleets, forcing the Italian fleet to invest a large number of escort forces and be forced to fight without air support. When the island of Malta was strong, nearly two-fifths of the Axis transport ships heading to North Africa were sunk; when the island was weak, more than 95% of the Axis transport ships arrived safely at their destinations. . Therefore, the Axis powers have always regarded Malta as a thorn in their side, and have tried every means to attack it, trying to weaken Malta's role, and tried every means to remove this "thorn in their side".

In December 1941, Hitler issued an order to the German army in the Mediterranean theater, stipulating that the task for 1942 was: "obtain air and sea control from southern Italy to North Africa and firmly hold it in their hands to ensure that The security of the sea routes to Libya and Cyrenaica, and especially the suppression of Malta at all costs... cut off the enemy's lines of communication through the Mediterranean and British supplies from Tobruk and Malta." The directive also appointed Marshal Kesselin. Commander-in-Chief of the German Army on the Southern Front. In addition, the German High Command sent the 2nd Air Force to Sicily with the aim of cooperating with the Italian fleet to strengthen the attack on the island of Malta and impose a sea and air blockade on it, hoping to defeat the island of Malta.

In the first half of 1942, the German army carried out a series of indiscriminate bombings on the island of Malta, destroying a large number of British combat aircraft on the island. In mid-May, Kesselring believed that he had completed the task of destroying Malta's defenses, so he transferred some units of the Second Air Force to the eastern front. The easing of the blockade on the island has given the island some breathing space. Britain took the opportunity to strengthen its air and naval forces on the island. At the same time, U.S. aviation forces also gradually entered into operations in the Mediterranean. At the end of May, the Allied forces once again established air bases throughout the Mediterranean and restored their previous combat effectiveness and defense capabilities. Especially on the island of Malta, from April 19 to June 5, the aircraft carrier transported 178 fighter jets to a group on the island. More importantly, the new torpedo aircraft transferred to Malta had a larger combat radius—from 100 nautical miles in 1939 to 400 nautical miles in 1942, exceeding the entire Mediterranean. Therefore, even if the Axis transport ships took the farthest roundabout route, they would not be able to escape the attacks of British aircraft. Even the Axis ships in the ports of Bardiya, Tobruk and Matruh would not be able to escape being attacked. fate. It became virtually impossible for the Axis powers to protect the fleet from attacks by British aircraft. Kesselring had to concentrate on bombing the island's airfield. In one bombing, German planes dropped 700 tons of bombs and destroyed 17 aircraft on the ground. However, the German bombers also suffered a powerful counterattack by British fighter jets, losing 65 aircraft, while the British army only lost 36 Spitfire fighter jets. By July 15, German bombers had to implement hit-and-run tactics to maintain their original strength.

In mid-to-late June, the Axis powers hesitated after their victory in North Africa and finally gave up the "Hercules" plan to occupy the island of Malta. With their heroic and fearless spirit, the defenders and residents of Malta withstood countless attacks from the enemy and passed through the most difficult moments. In early July, the British Army High Command decided to send back the submarines that had been forced to evacuate the island of Malta in April and May to restore the island's role as an offensive base. On July 20, the first submarine arrived in Malta. The role of the submarine force was quickly revealed: in August, the Soviet Union sank 7 Axis transport ships, with a total tonnage of more than 40,000 tons. By September, Malta had fully resumed its role as a base for surface warships, submarines and fighter jets.

"Cornerstone" Escort Campaign

Since the defeat of two British convoys bound for Malta in June 1942, the UK has not conducted routine escort campaigns. Important supplies such as anti-aircraft shells and aviation gasoline were transported to Malta by fast surface ships and submarines. However, the starvation problem faced by the defenders has not been solved. From March to August, only two damaged supply ships sailed to Malta. The supplies are far from enough. The island is particularly short of flour and ammunition. If it does not receive sufficient supplies in time, it will be difficult for the British defenders to hold on. Therefore, the British government decided to conduct another convoy campaign in mid-August and send a large transport fleet to Malta. The operation was codenamed "Cornerstone." The British high command knew that as long as Cyrenaica was controlled by the Axis powers, it would be absolutely impossible for the fleet to enter the island of Malta from the east. The "Energetic" convoy battle in June had proved this. The British fleet must concentrate on opening a passage from Gibraltar. To this end, Britain assembled a large convoy including modern cruisers and powerful destroyers to deal with Italian warships. At the same time, the United Kingdom and Egypt have vigorously strengthened the air force on the island of Malta to support Operation Cornerstone in the hope of success.

On the morning of August 10, 14 cargo ships set sail from Gibraltar and sailed through the Strait of Gibraltar towards Malta. The troops escorting the fleet included 3 aircraft carriers carrying 72 fighter jets, and the fourth aircraft carrier "Furious" carried fighter jets destined for Malta; the escort fleet also included 2 battleships, 7 cruisers, 24 destroyers, 8 submarines and more than 20 small ships. This escort force can be said to be the strongest in the entire war, and it is enough to show the importance that Britain attaches to this operation.

On August 5, the Italian Navy headquarters learned from radio interceptions that the British army was preparing to conduct a major activity in the Western Mediterranean. From the evening of the 8th to the 10th, the Axis powers further learned that a large fleet was divided into several groups and was sailing eastward through the Strait of Gibraltar. Based on this important information, the German and Italian military commanders immediately began to deploy troops to prevent the voyage. Unable to use battleships due to lack of fuel, the German and Italian forces dispatched a large number of air forces and 21 submarines, as well as cruisers, destroyers and torpedo boats, and set up five blocking lines on the way forward of the British fleet, aiming to force the British fleet to disperse. It was then wiped out by a powerful Italian cruiser force. A fierce maritime battle is about to begin.

In August and November, when the British fleet passed the blockade consisting of seven Axis submarines deployed between the Balearic Islands and Tunisia, the German submarine U-73 sank the aircraft carrier "Eagle". That afternoon, 37 aircraft took off from the aircraft carrier "Furious" and headed fiercely to the island of Malta, while the carrier returned to Gibraltar. On the way, the aircraft carrier was attacked by the Italian submarine "Dagapur". The British escort destroyer immediately counterattacked and sank the "Dagapur". At sunset German and Italian aircraft began a heavy bombardment, and submarines also launched an offensive, but no losses were caused to the British fleet.

On the morning of August 12, as the British fleet passed south of Sardinia, the German and Italian air forces launched another attack, severely damaging the aircraft carrier "Invincible", several transport ships were seriously injured, and a destroyer was seriously damaged. Sunk by German torpedo attack aircraft. That night, the main ships escorting the fleet returned to Gibraltar. The transport fleet was escorted by 4 cruisers and 10 destroyers and continued to move towards Malta. At this time, except for one cargo ship, the "Deucalion", which was injured and fell behind, the rest were sailing in line.

However, the fleet suffered a huge setback at the blockade in the Cape Bon area composed of 6 Italian submarines. The anti-aircraft cruiser "Cairo" and four transport ships were sunk, and the cruiser "Nigeria" was severely damaged. These two cruisers were the two control centers for combat escorts, and their loss caused huge chaos in the fleet. Under a joint attack by German and Italian bombers and torpedo planes, the cruiser "Manchester", a tanker and two transport ships were sunk in the waters off Panterella Island. On the morning of August 13, German bombers bombed the British fleet again and sank two ammunition ships. Later, under the protection of fighter jets from Malta, the remaining ships of the fleet escaped the fate of being wiped out. On the evening of the 13th, five transport ships carrying 32,000 tons of cargo finally arrived in Malta. One of the tankers brought much-needed fuel for the island's air force. In this escort operation, the British fleet and its escort ships were sunk 1 aircraft carrier, 2 cruisers, and 9 transport ships. The Axis powers lost about 60 aircraft and 1 submarine, and 2 cruisers were severely damaged. However, there was still no success in interdicting the transport operation.

The Allied fleet departed from Britain and its destination was French North Africa. This was the greatest victory achieved by the Italian navy and air force in the entire war, and it was also the last victory of the Axis powers in the Mediterranean naval battle. Overall, the British Navy did not receive effective support from the air force and was unable to repel the Axis air assault even though its naval power was superior. It was a tactical failure. However, the strategic implications of the Italian battleship fleet being unable to engage in combat for the first time in the war were far more profound. This showed that the Axis forces were declining, and the "Cornerstone" escort campaign was actually an elegy for the Italian Navy. The Allies, on the other hand, relied on their strong economic potential and solid material base to gradually strengthen their own strength. By the autumn of 1942, the strategic situation in the Mediterranean had been fundamentally reversed. Seize the initiative firmly in your hands.

Strike the supply lines in North Africa

In order to seize control of the sea in the Mediterranean and disrupt the maritime transportation of the Axis powers, the Allies began to mobilize huge naval and air forces to the Mediterranean region. By October 1942, Britain's naval power in the Mediterranean had grown rapidly, reaching an unpredictable level. Its number of ships had nearly doubled compared to half a year ago, with a total of 114 ships, including 3 battleships, 4 aircraft carriers, 14 cruisers, 63 destroyers and 30 submarines. However, the number of Italian warships increased by only 10 to a total of 78. The number of various warships increased by only 2 to 3 compared with half a year ago. At this time, the British military had an absolute advantage.

The intervention of U.S. aviation in the Mediterranean theater enabled the United Kingdom to make full use of aircraft carrier fighters to support maritime operations, greatly improving combat efficiency and delivering aircraft to the island of Malta. On October 11, the German and Italian air forces once again launched a fierce offensive on the island of Malta, attempting to eliminate the island's air force in one fell swoop. However, due to the strong reinforcements from the Allies, the air force on the island was greatly strengthened, and the Axis powers had to give up this attempt one week later. At this time, the basic strength of the German Navy had been concentrated in the Atlantic and Arctic Circle areas, making it difficult to deal with the Allied convoys. In the Mediterranean theater, the German army only had 15 submarines left. After January 1943, the number of submarines continued to decrease, and the Axis powers mainly relied on strengthening their air force to confront the Allies. However, because Germany had to take care of both the Atlantic and Eastern Front wars, the Allies' air force growth in the Mediterranean theater was much faster than that of the other side. By early 1943, the Allies had 3,000 aircraft; the Axis powers had only more than 1,700.

In this way, with the gradual recovery of the combat effectiveness of the navy and air force on the island of Malta, the continuous strengthening of the Allied air forces in the theater and the continuous weakening of the German and Italian forces, the Axis powers' shipping losses increased sharply, with the loss rate reaching 44% in October. . Of the 32,000 tons of supplies shipped to Rommel, only 20,000 tons were shipped; 10,000 tons of oil, which was crucial to Rommel's army, was loaded onto the ship. But only 4,000 tons arrived in North Africa. The German and Italian African Army was in the predicament of running out of ammunition, food, and fuel, while the British 8th Army received sufficient supplies of troops, equipment, and supplies. With the disparity in strength between the two armies, the British army launched the Battle of Aleman against the German and Italian forces in North Africa. Three days after the battle began, on October 26, a convoy carrying gasoline and ammunition that Rommel had placed great hope on was wiped out by the Allied navy and air force. This was a heavy blow to the Afrika Korps. After that, the Afrika Korps had no more Get adequate supplies.

Without gasoline, Rommel could not effectively utilize armored forces to carry out the armored maneuver warfare he was good at. He had to give up counterattacks many times, getting further and further away from victory.

Just as Montgomery led his troops to pursue Rommel's defeated army westward, the Allies unexpectedly launched the "Torch" landing campaign in North Africa on November 8, and their success once again dampened the morale of the Axis powers. On November 11, Hitler ordered "the establishment of a Tunisian bridgehead before the enemy troops enter Tunisia from Algiers." Three German divisions and two Italian divisions were ordered to undertake this task. The burden of providing logistical supplies for these troops naturally falls on the shoulders of the already overwhelmed Italian Navy. At this time, the Italian Navy can only fulfill its duties and do its best.

Prior to this, the Italian Navy Headquarters had explained to its Supreme Command that due to the rapid increase in the Allied naval power, in addition to the ongoing supply of Libya, the Italian Navy can no longer undertake any major operations. large-scale maritime support activities. In view of the sudden landing of the Allied forces in North Africa and Tunisia's precarious situation, the Italian Navy proposed to abandon shipping supplies to Tripolitania and fully reinforce the Tunisian defenders. Because Tunisia had greater strategic value to the Axis powers: it was the gateway to the Mediterranean and the bridgehead for future counterattacks in Africa. However, Hitler resolutely did not allow Rommel's army in Libya to implement a strategic retreat. In this way, the Italian Navy was forced to undertake a task beyond its capabilities - to provide supplies to Tripolitania and Tunisia at the same time.

On the afternoon of November 12, the first Italian fleet successfully arrived at the Tunisian port of Bizerte. The fleet consists of 2 transport ships and 5 destroyers, carrying 1,000 Italian troops and 1,800 tons of military equipment. In order to ensure the victory of supply, the Italian Navy immediately set up a headquarters in Tunisia, thus beginning the final stage of the maritime supply war. At this stage, the German and Italian forces completely lost control of the Mediterranean Sea.

Before the main force of the Allied forces entered Tunisia, the British army was still committed to providing supply opportunities to Libya. In November, the Italian Navy transported oil, tanks, and artillery to the five divisions that arrived in Tunisia by air. When the supplements reached more than 30,000 tons, more than 13,000 troops were shipped. Relying on the reinforcements of these soldiers and equipment, the German and Italian forces completely shattered the Allied forces' attempt to quickly capture Tunisia and Bizerte.

At the same time, German and Italian submarines were also extremely active along the coast of North Africa, effectively attacking Allied shipping. On November 10, an Allied coal ship and a destroyer were sunk by a German submarine. The next day, four more transport ships were sunk. Since mid-November, the German Navy has organized forces to blockade the Atlantic coast of North Africa from the sea, deploying 25 submarines west of Gibraltar. The main task is to cut off the Allies' supply to the landing troops who have landed ashore. In addition, the German army also intensively set up two parallel 120-nautical-mile-long mine obstacles between Sicily and the coast of Tunisia. Despite the above measures, there was no serious impact on Allied shipping in the Mediterranean. As of December, the Allied forces had only lost 16 transport ships in the Mediterranean. However, the Axis powers are at the end of their strength and will fail without attack.

With Cyrenaica falling to the British, lines of communication to Malta were open, and the island's siege was finally broken. The British army once again invested a large amount of troops and material resources to strengthen the island's combat power. It not only increased the number of submarines on the island, but also began to station surface ships. From December 1942, the 15th Cruiser Squadron, the Fleet Destroyer "K" Group and the 10th Submarine Area Fleet began to be stationed there. In addition to the cruisers and destroyers that serve as assault missions, a number of offshore fleets have also been organized on the island of Malta. They are composed of gunboats, torpedo boats and other small ships, which greatly strengthened the defense and combat effectiveness of the island of Malta.

Another Q fleet, composed of cruisers and destroyers, entered the port of Boni in Algeria on November 13, dealing a fatal blow to the Italian navy responsible for transporting supplies to the Tunisian garrison. Poni was the advancing point to Bizerte and the Straits of Sicily, strategically controlling the waters south of Sardinia. Together with the island of Malta, it became a pliers in the hands of the Allies against the Strait of Sicily. Under this situation, the Axis powers' maritime supply lines to Africa were actually paralyzed. Although the decisive Battle of Tunisia had not yet begun, Axis forces in Africa were already dying.

The Allied attention soon turned from the Libyan supply lines to the Sicilian Strait. The air force on the island of Malta conducts 24-hour air patrols over the strait to cooperate with the Allied navies to prevent the Axis powers from transporting reinforcements to Tunisia, creating good conditions for the complete elimination of the German and Italian African armies.

On the night of December 1, the British Q Fleet stationed in Bonny set sail and attacked an Italian escort transport fleet for the first time. The four transport ships of this fleet were fully loaded with 2,000 officers and soldiers and dozens of tanks and ammunition, and were escorted by five destroyers and headed for Tunisia. The Q fleet relied on superior radar and naval guns to quickly sink three Italian escort destroyers and severely damage one destroyer. The only Italian destroyer that was not killed saw that the situation was not good, and cruelly abandoned the transport fleet and fled in a hurry. The Italian fleet was fiercely attacked by the British Q fleet, and no one was spared. The British ships were intact.

At the same time, to the west of Sicily, north of Boni, an Italian oil tanker loaded with fuel urgently needed by the Tunisian defenders was discovered by the fleet aviation from the island of Malta, and was instantly hit by a torpedo plane and killed. seabed.

In the following two nights, four more Italian ships were destroyed by the Allied navy and air force, including the Italian destroyer "Lupo", which had repeatedly made military exploits for the Axis powers.

The Italians failed to achieve success with night shipping, so they changed tactics: crossing the Sicilian Channel during the day under the cover of fighter planes. At the same time, in order to protect against attacks by the British Navy's surface combat fleet, the Italians began to lay two mine defense lines at the end of November. The defense line extends forward from Bizerte and Tunis across the Strait of Sicily for 80 nautical miles, leaving only a narrow shipping channel and forming a powerful protective barrier.

The Allies soon learned about the corridor that was about 50 nautical miles wide through which the Italian fleet passed, so they used the minelayers on Malta Island and Poni Harbor to quickly sail into the corridor at sunset. Bray, leave before daybreak. After paying a heavy price for passing through this corridor, Italian ships discovered that between the Egadi Islands and the bases in Tunisia, there was only an "alley" that was 40 nautical miles long and no more than 1 nautical mile wide. It must be difficult to escort a large mixed fleet through a waterway that is 1 nautical mile wide and 40 nautical miles long without navigation marks, coupled with fog and frost in the middle of winter, rough waves and Allied air raids. In this way, the Italian Navy's daytime shipping plan also failed and had to change its navigation route.

In December 1942, the Italian navy and merchant fleet made every effort to provide supplies to its North African troops at any cost, and the total tonnage of cargo carried reached the highest level of more than 212,000 tons. However, at least 68,000 tons of them were sunk by the Allies, and 15,000 tons were damaged, with a loss rate of 40%. Among them, the loss rate of materials shipped to Libya was 52%, and the loss rate of materials shipped to Tunisia was 23%. From January to December 1942, the Allies sank 106 German and Italian ships in the Mediterranean, with a total tonnage of more than 177,900 tons. The supply of Germany and Italy failed.

After the Allied forces occupied the Algerian airport, in January 1943, the U.S. General Spaatz led the U.S. 12th Air Force to quickly join the Mediterranean operations. Their combat skills of high-speed and low-altitude bombing dealt a heavy blow to the Italian Navy. At this point, the Allies had achieved decisive air superiority in the Mediterranean theater. Combat aircraft could not only sink Axis ships at sea, but also conduct indiscriminate bombing of enemy ships in ports and harbours. In January alone, the Allied air forces dispatched more than 3,000 aircraft sorties to conduct raids on enemy ships in ports and on the high seas. In that month, the Axis powers dispatched 51 cargo ships to North Africa, 11 of which were sunk by submarines, 4 by surface ships, 2 hit mines, 7 were sunk by aircraft, and 7 more It was severely damaged by Allied air strikes, with a loss rate as high as 55%. Italians ruefully called the route to Tunisia the "death line."

By the end of 1942, the German and Italian troops in Tunisia could only rely on rushed supplies and favorable winter rains, which temporarily delayed the Allied advance. Rommel's army in Libya was in a desperate situation, running out of ammunition and food. The army needed at least 80,000 tons of supplies every month, but only received 24,000 tons in December, and finally had to abandon Tripolitania. In mid-February 1943, they retreated to the Mares defense line in Tunisia and held the gateway to Tunisia with the belief of not fearing sacrifice.

After the Allied forces resumed their offensive in March, they decided to first remove the nail in the Mares Line of Defense. During this period, the Allied navy and air force once again exerted their huge advantages and severely attacked the enemy's supply lines and transportation forces. By March, the Allies had a large number of American 4-engine bombers, which could effectively carry out large-scale daytime bombing of transport ship loading points and escort transport fleet marshalling points in Sicily and other coastal areas of Italy and Greece. In one attack, 22 American "Flying Fortress" aircraft destroyed a transport ship in the port of Palermo, Sicily. On April 10, U.S. bombers launched a sudden attack on the last two Italian heavy cruisers anchored in the port of La Maddalena in Sardinia, sinking the cruiser "Trieste" and destroying the "Gorizia". Significant progress has been made.

A series of bombings carried out by the Allied Air Force greatly weakened Italy's escort force. In the first quarter of 1943, the number of Italian warships used to escort the Tunisia route did not exceed 10 per day. By the end of February, the number was reduced to 5, and the number dropped sharply. From then on, the remaining escort warships had almost no chance to enter the port to rest. They kept wandering back and forth in the Sicily Strait, with as many as twenty-seven or eight days of duty per month. The crew is extremely tired and the escort capability is reduced. In February, the Axis powers sent 34 transport ships to Tunisia, of which only 20 arrived. In March, 44 transport ships were destroyed and 23 sunk by the Allies.

In the early days of the Tunisian campaign, the average loss rate of the Axis powers on the sea lines of communication was 25% to 30%. In the last two months of April and May, the losses were particularly serious, as high as 50%. Even more than 50%. At this point, the line of communication between the Axis powers and the Tunisian defenders has actually been cut off, and it is even more difficult to continue supplying. Under this circumstance, General Arnim, commander of the German and Italian Army Group Africa, reported to Hitler his situation of lack of food and fuel. Marshal Kesselring also suggested abandoning Tunisia and withdrawing the remaining troops to the mainland to preserve their strength, but Hitler flatly refused. This means that the army, navy and air force of the Axis powers will continue to make unnecessary sacrifices in Africa.

In order to boost morale and support the Tunisian defenders, the Axis high command used all available destroyers, torpedo boats, and transport ships to transport troops and supplies to Tunisia. In April, up to 60% of the supply ships were sunk and damaged by the Allies. On the last day of April, three Italian destroyers carrying 900 troops did not escape their fate and were buried in the sea. By the end of April, under the effective interception of American fighter jets, the Axis powers' air transport activities also stopped. Unwilling to fail, the Axis powers dispatched a large 8,000-ton cargo ship on the night of May 3, fully loaded with ammunition, bombs and mines, and sailed to Tunisia under the escort of a torpedo boat. They were sunk near Cape Bon by three British destroyers from Malta. At this time, the Tunisian garrison, which had not received effective supplies, was in an extremely urgent situation.

On May 7, the Allied forces successfully occupied the ports of Tunis and Bizerte, the last supply bases for the German and Italian armies in North Africa. The remnants of the German-Italian Army Group Africa withdrew to Cape Bon in northern Tunisia and reported to headquarters that they were no longer able to accept shipping supplies. However, Hitler still asked for reinforcements to be sent. That night, the last three German cargo ships sailed towards Cape Bon. After they safely crossed the Strait of Sicily, they could not find a port to unload their cargo. When they hesitated, they were blown into pieces by Allied aircraft. The fragments floated across the sea in an extremely spectacular manner.

In the final stage of the Tunisian campaign, the Allied high command expected that the enemy would withdraw from Cape Bon by sea or air. Therefore, the combat activities of the Allied naval and air forces on the German-Italian communication lines developed accordingly. It became a blockade of the coast, designed to annihilate the Axis forces on the continent. For this reason, the escort transport fleet temporarily stopped sailing to the island of Malta and did not operate in the offshore area. All forces were concentrated on blocking the enemy forces in Tunisia. Here the Allied forces carried out the first close blockade. Destroyers, torpedo boats and small ships participating in the blockade were deployed in two lines in a semicircle near Cape Bon.

The gunboats opened fire on the Axis forces concentrated on the Cape Bon Peninsula and effectively controlled the enemy artillery firing at the ships. Allied bombers and fighter jets provided support and cover to the ships, annihilated enemy aircraft at the airport and in the air, and prevented the remaining Axis forces from evacuating by transport aircraft. This blockade shattered all possibilities of the Axis forces' dream of withdrawing from Tunisia. In addition to hundreds of people who fled to Sicily in the dark on small ships, nearly 300,000 Axis troops surrendered to the Allies on May 13. At this point, the African War ended victoriously.

With the entire North African coast in Allied hands, Allied shipping could flow unimpeded in the Mediterranean. At this time, German submarines were unable to carry out large-scale attacks and could only operate in secret. Their numbers and threats were insignificant and gradually decreasing. The Luftwaffe sometimes attacked the Allied navy and harassed its shipping in the Mediterranean, but its power was nowhere near enough.