Operation Attack on the BN.7 Convoy

The 'Attack on the BN.7 Convoy' was a naval engagement in the Red Sea between an Italian destroyer force and a British-led force escorting the BN.7 convoy of 32 merchant vessels (20/21 October 1940).

The Italian attack failed, inasmuch as only one merchant vessel was damaged, and then only slightly. After a chase, the British destroyer Kimberley torpedoed the Italian destroyer Francesco Nullo, which was beached on Harmil island off Massawa in Eritrea. Kimberley was also hit and disabled by the fire of an Italian shore battery on this island, and was towed to safety by the light cruiser Leander.

Manoeuvring in two groups to increase the chance of intercepting the British convoy had succeeded, but for the Italian lost the benefits of concentration against the escorts, and a destroyer was lost for no result. The British command at Aden criticised all the escorts but Kimberley for lack of aggression but at the same time leaving the convoy defenceless to undertake a risky chase at night and in misty weather. The Italians made another fruitless sortie on 3 December, cancelled one in January 1941 after the destroyer Daniele Manin had been damaged by a bomb, and conducted an abortive sortie on 24 January.

The Red Sea is notable for its high temperatures and considerable humidity, its shores vary from desert to high mountain ranges, and navigation is fraught with danger as a result of offshore reefs and false horizons caused by atmospheric refraction.

In May and early June 1939, French and British military officials met at Aden to devise a common strategy to retain control of the waters around Italian East Africa should Italy declared war. It was expected that in that event Italy could close the Mediterranean Sea to Allied maritime traffic and that supplies to the Middle East would therefore have to be transported round the Cape of Good Hope and thence northward through the Indian Ocean and ultimately the Red Sea. Control of the Gulf of Aden, the Red Sea and the Gulf of Suez at the northern terminus and the maintenance of the bases at Aden and Djibouti, the latter in French Somaliland were equally important but a withdrawal from French and British Somaliland had also be contemplated.

The British-controlled Port Sudan lay on the western coast of the Red Sea, about 690 miles (1110 km) between Suez in the north and the Strait of Bab el Mandeb in the south. The Italian port of Massawa in Eritrea was about 400 miles (645 km) to the north and Aden about 115 miles (185 km) to the east of the Strait of Bab el Mandeb. The ports along the coast of Italian Somaliland and the entrance to the Red Sea were to be blockaded in 'Begum' to prevent the delivery of reinforcements and supplies to the Italian forces. Allied merchant ships in the Indian Ocean and the Red Sea were to proceed in escorted convoys. Naval ships were to sweep mines, patrol the Gulf of Aden and the Strait of Bab el Mandeb in order to isolate Contrammiraglio Carlo Balsamo di Specchia-Normandia’s Italian Flottiglia del mar rosso (Red Sea Flotilla) and protect Aden from attacks by Italian ships; the Italian naval bases in Eritrea were to be attacked.

In April 1940 the Royal Navy established the Red Sea Force under the command of Rear Admiral A. J. L. Murray with the light cruisers Liverpool, Australian Hobart and New Zealand Leander, of which the last was replaced by Liverpool on 26 May. By September the Red Sea Force comprised the light cruisers Hobart, Leander and Caledon, the anti-aircraft cruiser Carlisle, the destroyers Kimberley, Kingston and Kandahar, the sloops Flamingo, Auckland, Shoreham, Grimsby, Indian Clive, Indus and Hindustan, and Australian Parramatta. Aden was the base for two minesweepers, two small armed merchant cruisers and two armed trawlers. Ships attached on a temporary basis included the light cruisers Ceres and Colombo, and the heavy cruisers Dorsetshire and Shropshire.

The Italian naval and air bases in East Africa were conveniently sited for the launch of attacks on shipping in the Red Sea and the Indian Ocean. Massawa was the home port of the Flottiglia del mar rosso, had been fortified and lay behind numerous islands and reefs with mined approaches; there was a smaller base at Assab. The scout cruisers Pantera and Leone, the latter under the command of Capitano di Fregata Paolo Aloisi, had the unusually powerful armament of eight 120-mm (4.72-in) guns, in four centreline turrets: only two turrets could aim directly fore or aft, but the eight-gun broadside was unique for what were in effect large destroyers. The ships also carried two 40-mm anti-aircraft guns, four 20-mm cannon, four 533-mm (21-in) torpedo tubes and 60 mines. The 'Sauro' class destroyers had an armament of four 120-mm (4.72-in) guns, two 40-mm anti-aircraft guns, two 13.2-mm (0.52-in) machine guns, six 533-mm (21-in) torpedo tubes and 52 mines. After Italy had entered the war, the fuel stored for the Italian ships based at Massawa could only diminish under the British blockade, and the steady accumulation of mechanical faults, fuel depletion and the enervating effect of the climate exercised severe constraints on the operations of the Flottiglia del mar rosso.

In June 1940, four of the eight Italian submarines based at Massawa were lost, but the Regia Aeronautica began operations over the Red Sea and on 11 June a Savoia-Marchetti SM.81 three-engined warplane flew a reconnaissance sortie. On 16 June, the Italian submarine Galileo Galilei sank the 8,215-ton Norwegian tanker James Stove, sailing independently, about 14 miles (22 km) to the south of Aden. On 19 June, Hobart despatched its Supermarine Walrus single-engined biplane amphibian to bomb an Italian wireless station on Centre Peak island between Massawa and the Arabian coast. On 2 July, the BN.1 convoy of six tankers and three freighters assembled in the Gulf of Aden. On 8 July, an SM.81 of the 10a Squadriglia flew a long-range reconnaissance sortie over southern Sudan and the Red Sea and was attacked by a Vickers Wellesley single-engined multi-role warplane: the SM.81 was damaged, hit an island while attempting to force land, bounced into the air and flew on at wave-top height, with the Wellesley flying above and to one side for its gunners to keep firing. After ten minutes the Italian aircraft hit the sea and lost its wings.

Between 26 and 31 July, the submarine Guglielmotti failed to find two Greek merchantmen, and a sortie by the torpedo boats Cesare Battisti and Francesco Nullo came to nothing. Guglielmotti sortied once again between 21 and 25 August, Galileo Ferraris from 25 to 31 August, Francesco Nullo and Sauro from 24 to 25 August, and the destroyers Pantera and Tigre between 28 and 29 August. All failed to find targets despite agent reports and sightings by air reconnaissance. On 4 September, Italian bombers attacked the merchant vessel Velko and inflicted serious damage, and on the next day five Savoia-Marchetti SM.79 three-engined medium bombers attacked the BS.3A convoy. A Bristol Blenheim IVF twin-engined fighter on convoy patrol attacked the bombers but was damaged. On 6 September the convoy was attacked by another SM.79. The BN.4 convoy was spotted by air reconnaissance and on the night of 5/6 September, Cesare Battisti, Daniele Manin and Sauro sortied. The destroyers Leone and Tigre followed on 6/7 September but the found nothing.

Patrolling farther to the north, the submarines Galileo Ferraris and Guglielmotti also failed to find the BN.4 convoy, but Guglielmotti torpedoed the 4,008-tin Greek tanker Atlas straggling behind the convoy to the south of the Farasan islands. Air reconnaissance also found the BN.5 convoy of 23 ships but Leone, Pantera, Cesare Battisti and Daniele Manin, together with the submarines Archimede and Guglielmotti, failed to find the convoy. The 5,280-ton motor vessel Bhima was damaged in an Italian air attack: one man was killed and the ship was towed to Aden and beached for repairs. On 19 September five SM.79 bombers attacked a convoy and outpaced two Gloster Gladiator single-engined biplane fighters which tried to intercept them. On the next day, Italian bombers were driven off by Blenheim fighters. On 15 October, three SM.79 bombers were prevented from attacking another convoy by two Gladiator fighters and one Blenheim. Five days later, individual SM.79 bombers attacked the BN.7 convoy.

The BN.7 convoy was northbound through the Red Sea and comprised 32 British, Norwegian, French, Greek and Turkish merchant ships. The escort comprised Commander J. Riovett-Carnac’s light cruiser Leander, Commander J. S. M. Richardson’s destroyer Kimberley, the 'Egret' class sloop Auckland, the 'Grimsby' class sloops Yarra (Australian) and Indus, and the 'Hunt' minesweepers Derby and Huntley. The BN.7 convoy was nearing Perim, a volcanic island off the south-western coast of Yemen in the Strait of Bab el Mandeb during the afternoon of 19 October when an aeroplane dropped four bombs close astern of one of the merchantmen. Leander and Auckland opened fire on the aeroplane as it flew away to the west; shortly before dark, an landing gear wheel of an Italian aircraft was recovered 17 miles (28 km) to the south of the island. In the course of the following morning, Italian aircraft dropped four bombs, two of which fell ahead of the convoy and two bombs harmlessly astern of the French liner Félix Roussel, which was carrying New Zealand troops to Suez. At dusk Leander took station on the port beam of the convoy between it and the Italian base at Massawa, which flanked the line of advance, and the convoy zig-zagged through the night.

The Italian flotilla sailed on 20 October with the destroyers operating in pairs: Sezione I comprised Capitani di Fregata Moretti degli Adimari’s faster Sauro and Capitano di Corvetta Costantino Borsini’s Francesco Nullo, while Sezione II comprised the more heavily armed but slower Pantera and Leone, which were to divert the convoy escort and would then attack the convoy with torpedoes. At 21.15 the two sections divided and at 23.21 Pantera sighted the convoy’s smoke. Pantera signalled Sauro and moved ahead of the convoy to intercept, with Leone following 875 yards (800 m) behind her. The convoy was about 40 miles (65 km) to the north-north-west of Jabal al Tair island at 02.19 on 21 October, when Leander sighted two patches of smoke bearing north.

Auckland reported two destroyers 4.6 miles (7.4 km) distant, and Leander altered course to intercept, the captain assuming that the Italian ships would run for home through the South Massawa Channel. After a challenge from Auckland, Pantera fired over Yarra at the convoy, inflicting some splinter damage to a lifeboat on the convoy commodore’s ship. Auckland opened fire and the Italian ships separated and turned away at full speed to the west-south-west in the direction of Massawa, firing their aft guns. The destroyers were broad on the port bow of Yarra when Pantera fired two torpedoes at 23.31 and another two at 23.34. Yarra avoided two torpedoes by turning toward them and combing their tracks, and observers in Yarra thought that the leading Italian vessel was hit by their fourth or fifth salvo.

Sauro and Nullo had been manoeuvring into a more favourable position after receiving Pantera's sighting report, turned toward the convoy and spotted Leander at 01.48 Sauro fired one torpedo at Leander, but this missed and Leander opened fire but lost sight of Sauro after two minutes. Sauro made another torpedo attack at 02.07 and then turned away toward Massawa. Nullo was not able to attack after its rudder jammed for several minutes and the boat went round in circles, losing contact with Sauro. Borsini ordered Nullo toward the Italian batteries on Harmil island off Massawa. When the gunfire ceased, Leander altered course to the north-west to intercept the ships in the South Massawa Channel (otherwise the Harmil Island Passage) and at 02.45 opened fire with her 6-in (152.4-mm) guns on a ship that was firing red and green tracer. The range was increasing and the ship was lost to sight after the first salvoes.

Leander altered course to the west in order to bring all eight of her main guns to bear if the ships were making for the South Massawa Channel. At 02.20 Leander spotted Nullo by searchlight and exchanged fire for about 10 minutes at a range of about 4,600 yards (4205 m), Leander scoring several hits which damaged Nullo's gyrocompass and gunnery director. At 02.51, Leander lost contact in the haze and ceased fire after firing 129 6-in (152.4-mm) rounds. Nullo headed toward Harmil island with Leander in pursuit, and at 03.00 Leander challenged a destroyer which, it transpired, was Kimberley, also in pursuit. After five minutes, the cruiser altered course to the east to rejoin the convoy as the Italian ship was drawing away at the rate of 7 kt, and and the convoy was still vulnerable to attack.

In the early hours of 21 October, Kimberley continued to steam at her maximum speed and at 03.50 sighted smoke ahead of her, apparently from two ships retiring at high speed. At 05.40, off Harmil island, look-outs on Kimberley and Nullo spotted each other’s ship at a range of 14,250 yards (13030 m). Borsini assumed that the other ship was Sauro and when Kimberley opened fire at 05.53, Nullo was taken by surprise, not returning fire for four minutes. Kimberley closed the range to 5,000 yards (4570 m), and 06.20 Nullo scraped a reef, which damaged a propeller and sprang a leak. As Nullo rounded Harmil island at about 06.25, she was hit once in the forward engine room and once in the aft engine room. Nullo lost all power, and Borsini gave the order to abandon ship and steered towards Harmil island. The Italian ship’s upper works were hit by shell splinters and the crew abandoned ship, while Borsini tried to run Nullo aground on the island. Nullo was then hit by the second of two torpedoes at 06.35, and broke in two. Borsini and his assistant declined to leave the ship and were drowned. At 06.15 the four 120-mm (4.72-in) guns on Harmil island engaged Kimberley and hit her in the engine room, wounding three men and holing the steam pipes. While adrift 10,000 yards (9145 m) from the shore battery, Kimberley silenced two of the guns and wounded four gunners with 45 HE shells from No. 3 mounting.

Kimberley managed to get under way, her speed reduced to 15 kt, and the shore battery ceased fire when Kimberley was 19,000 yards (17375 m) distant. Kimberley had fired 596 rounds of semi-armour piercing and 97 high explosive shells. Leander left the convoy and at 06.54 increased speed to 26 kt. By 07.34, Leander was making 28.7 kt, and soon after this Kimberley reported that she was steaming to the east at 15 kt on one engine. At 08.25, Leander was 18 miles (29 km) east by north of the Harmil South beacon and slowed to 10 kt. Leander circled near Kimberley to keep freedom of manoeuvre, in case Italian bombers appeared. Kimberley had lost water in her boilers and Leander sent a boat with three shipwrights and an engine room artificer; a wounded rating was transferred to the cruiser for medical attention. At about 10.00, Leander took Kimberley in tow.

In August the British had run four convoys of the BN series and four of the reciprocal BS convoys, five in September and seven in October, the BN northbound convoys comprising 86 ships and the BS southbound convoys 72 ships. Despite agent reports and sightings by the Regia Aeronautica, Italian submarines and ships had frequently failed to make contact with the convoys, and in fact only six air attacks were managed in October and none after 4 November. During the 'Attack on the BN.7 Convoy', the British found that they were at a disadvantage in night fighting as they were temporarily blinded by the flash of their own guns, while the Italian ships used flashless cordite and had good tracer ammunition. With the exception of Kimberley, the British convoy escorts were criticised for a lack of aggression, despite the danger of abandoning the convoy at night and in poor visibility. The Italians had managed to make two torpedo attacks as planned, but the separation of their destroyers into two sections, after previous sorties had failed to find any ships, meant that neither section had the firepower to face the British escorts.

Of the Nullo's 120-man crew, Borsini declined to abandon ship and when his assistant, a seaman named Vincenzo Ciaravolo, realised the fact he jumped from his lifeboat to accompany his captain, and both men were drowned. Of the ship’s company, 12 men were killed and 106 were rescued by sailors of the Harmil island battery. Kimberley was out of action until 31 October, then returned to service capable of only a reduced maximum speed until fully repaired in the spring of 1941.

In subsequent operations, at 10.00 on 21 October Leander opened fire on three aircraft flying at 13,125 ft (4000 m), which bombed about 200 yards (185 m) ahead of the ship, two more bombs turning out to be duds. No damage resulted, and Leander and Kimberley rejoined the BN.7 convoy just after 12.00. In the afternoon, Leander transferred the tow of Kimberley to Kingston, which left the convoy with Kimberley for Port Sudan in the morning of the following day. The southbound BS.7 convoy of 20 ships was met by the convoy escorts in the afternoon of 23 October and after an uneventful passage, dispersed in the area to the east of Aden on 28 October. Later on 21 October, three Blenheim bombers of No. 45 Squadron found and bombed the wrecked Francesco Nullo. The Italians made another fruitless sortie on 3 December, cancelled one in January 1941 after Daniele Manin had been damaged by a bomb, and on 24 January sortied again with no result.

On the night of 2/3 February 1941, the Italian destroyers Pantera, Tigre and Sauro departed Massawa to intercept a convoy known to be in the area. This BN.14 convoy comprised 39 merchant vessels escorted by the cruiser Caledon, the destroyer Kingston and the sloops Indus and Shoreham. Sauro sighted the convoy and fired three torpedoes, then fired again at a ship seen in a cloud of smoke, before turning away at high speed. The two other ships did not receive Sauro's sighting report, but 10 minutes later Pantera spotted the ships and fired torpedoes, hearing explosions and claiming probables on two merchantmen; Tigre failed to find the convoy. Close to Massawa in the South Channel, Sauro encountered Kingston but had run out of torpedoes. Fearful that the British were trying to spring an ambush, the other Italian ships converged on Sauro and radioed for air cover at dawn, reaching port unharmed. Local Italian press reports claimed that two ships had been hit but this report was mistaken.