MTM: the Italian Navy’s Explosive Motorboat II



Date: 26 July 1941

Place: Grand Harbour, Valletta, Malta

Attack by: Italian MTM boats and Maiali torpedoes

Target: Allied warships and transports at anchor

The MTM pilots who had made the hazardous and successful attack at Suda Bay had all survived, but the last major operation in which MTMs were deployed (their role subsequently being taken over by the small, torpedo-armed MTSM and SMA boats mentioned above) proved to be a true suicide mission – both in execution and, it may be suspected, in planning. At Suda Bay, the frail explosive boats had been pitted against an unprepared enemy and improvised defences at a location that had been thoroughly reconnoitred. This was not the case with the newly-chosen target: after MTMs had been launched to make seaborne reconnaissance of such Allied anchorages as Porto Edda (Sarandë) in southern Albania, and Corfu, the choice fell on the Allies’ Mediterranean bastion – Malta. In spite of its formidable defences and the lack of intelligence concerning them, Grand Harbour at Valletta was designated the target.

It must have been obvious at the planning stage that self-sacrifice would be unavoidable if the attackers were to penetrate the anchorage and that, even if the penetration were made, there would be little chance of survival for the crews of small boats under concentrated fire in the narrow, crowded harbour. This was certainly realized by Maggiore Genio Navale (Major, naval rank) Teseo Tesei, co-inventor of the Pig, who maintained that the attack should be made simply as a demonstration of Italian gallantry and determination, as an inspiration to “our sons and Italy’s future generations”. Tesei, who had already been told that his exploits in Pigs had overstrained his heart and that he faced death if he did not retire from operations, wrote a farewell letter shortly before the Malta mission in which he stated his intention of “winning the highest of all honours, that of giving my life for the King and the honour of the Flag.” Tesei’s determination was matched by that of Cdr Moccagatta and, faced with such enthusiasm, Admirals de Courten and Campioni of the Naval Chiefs of Staff gave somewhat grudging approval to the mission. It will be noted that, as in Japan, the employment of suicidal weapons and tactics was, at first, more enthusiastically advocated by junior officers than by their superiors; ie, by the men who would be intimately concerned with the operation of such weapons.

After a further series of seaborne reconnaissances, it was decided to mount the attack on Malta on the night of 27–28 June. Late on 27 June, a small task force of MTMs towed by MTBs sailed from Augusta, eastern Sicily, where training had been underway since April. Foul weather forced a return to base. Two nights later, Moccagatta’s force tried again: this time, engine failure on two MTMs resulted in a further postponement – until the corresponding dark of the moon in July. Profiting from experience, Moccagatta now changed the composition of his task force: instead of being towed to the operational area the MTMs would be carried aboard the fast sloop Diana (1,764 tons, 1792 tonnes; originally built as Mussolini’s official yacht) and would be led into the attack by an MTSM and, at the insistence of Major Tesei, by two Pigs. The human torpedoes would, in fact, spearhead the attack: one would blow a hole in the net defences of Grand Harbour; the other would make a diversionary raid on the Royal Navy’s submarine base at Marsa-Muscetto, in the western arm of Valletta harbour. An air raid was timed to coincide with the surface attack and was expected fully to occupy the harbour batteries.

Moccagatta’s force sailed from Augusta at sunset on 25 July. Aboard Diana (LtCdr Mario Di Muro) were nine MTMs; an MTSM, in which LtCdr Giobbe would direct the attack; and a small, electric- powered (and therefore silent-running) motorboat which would carry the two Pigs to their launching point. The Pigs were carried from Augusta on the 20-ton (20.3 tonne) motor torpedo boats MAS 451 (SubLt Giorgio Sciolette) and MAS 452 (Lt G. Batta Parodi). The Pig crews were Major Tesei with CPO Alcide Pedretti and Lt Franco Costa with Sgt Luigi Barla. Thus, the commander of 10th Light Flotilla (Moccagatta, aboard MAS 452) and all his principal officers intended to play an active part in the desperate enterprise; even the Flotilla’s chief medical officer, Captain Surgeon Bruno Falcomatà volunteered as a member of MAS 452’s crew. Although the mission had not been planned to take advantage of the fact, Valletta now offered an excellent selection of targets, for the transports of the hard-fought “Substance” convoy had entered Grand Harbour on 24 July.

Gallant Failure at Valletta

Nine MTMs were launched from Diana some 20nm (23 miles, 37km) off Malta at some time before midnight on 25 July. One sank immediately. The remaining eight, with the electric launch carrying the Pigs, headed inshore, escorted by the MTSM and the two MTBs. By 0300 on 26 July, the electric launch was within 1,100yds (1000m) of the entrance to Grand Harbour, at which point the Pigs were to launch. Engine failure on the Pig of Costa and Barla delayed the launching time by at least one hour (en route to their target, Marsa-Muscetto, the engine failed again and, unable to complete their mission, the two men were later taken prisoner). Tesei and Pedretti had the vital task of destroying the steel-plate-and-mesh anti-torpedo net, suspended from a two-span bridge, that guarded the narrow passage leading into Grand Harbour below Fort St Elmo. In spite of the delay in launching, Tesei made it clear that he intended to destroy the net at the appointed time (0430) – even if, as seemed likely, this entailed the self-destruction of himself and Pedretti. Meanwhile, Giobbe told the MTM pilots that if, following up Tesei, they found the barrier still intact, the leaders must sacrifice themselves in order to ensure that at least one boat penetrated the harbour and reached Allied shipping.

But by the time the Pigs were on the way, the harbour defence force was on the alert. Diana’s arrival and departure had been logged by surface radar and, because the diversionary raids by Italian aircraft were sporadic and ill-timed, the small boats’ engines had been heard. Even so, the Pig crewed by Tesei and Pedretti was able to reach the St Elmo bridge where, at 0425, true to his word, Tesei detonated the warhead of his torpedo immediately, sacrificing himself and Pedretti – but failing to breach the net. To seaward, hearing the explosion, Giobbe ordered the MTMs in to the attack.

In the first light of dawn, the MTMs hurled themselves at the still-intact barrier. In the leading boat, SubLt Roberto Frassetto flung himself clear just before the impact: his MTM struck the netting but failed to detonate. Following him, SubLt Aristide Carabelli remained at the helm until the last, perishing in a massive explosion that seriously wounded the swimming Frassetto, breached the netting – and brought down one of the bridge spans, rendering the boat channel impassable. As SubLt Carlo Bosio led in the remaining boats, their path was illuminated by searchlights, and 6-pounder batteries, Bofors AA guns and machine guns opened up from the shore. Caught in the blocked channel under a savage crossfire, the MTMs were soon sunk; Bosio was killed and the surviving pilots, all wounded, were captured.

As the light improved, some 30 Hawker Hurricanes joined the battle and, although opposed by 10 Macchi C.200 Saetta fighters (which succeeded in shooting down one Hurricane, but lost three of their number) located and attacked the two MTBs and the two smaller motorboats which had been standing by to take off any surviving MTM and Pig crewmen. MAS 451, raked by cannon fire from the Hurricanes, blew up and sank, killing four of her 13-strong crew. The electric launch was also sunk, and aboard MAS 452, Moccagatta, Giobbe, Falcomatà, Parodi and four other men were killed by gunfire. Abandoning MAS 452, 11 survivors succeeded in reaching Diana. Fifteen men had been killed, among them the senior officers of the 10th Light Flotilla, and 18 captured in the gallant but ineffective action.

Abortive Missions with MTR boats

Thereafter, the MTMs played little part in the 10th Light Flotilla’s activities. However, the explosive boat concept was adopted by the German Navy and Cdr J. Valerio Borghese (who succeeded Moccagatta in command), remaining faithful to the Axis cause even after Italy’s surrender, passed on his experience to German volunteers.

Before Italy’s collapse, however, two abortive missions were launched with the smaller MTR explosive boats. In mid-1943, following the Allied invasion of Sicily, it was planned to attack shipping in Syracuse harbour with MTRs. The submarine Ambra (LtCdr Renato Ferrini), carrying three MTRs in the deck cylinders originally designed for the transportation of Pigs, stood off Syracuse on the night of 25 July 1943. But the activities of German U-boats had put the harbour defences on full alert: picked up on the radars of patrolling aircraft, Ambra was bombed, depthcharged, and forced to retire with heavy damage, including the crushing of the MTRs’ cylinders.

A similar mission was planned for 2 October 1943, when the submarine Murena (Cdr Longanesi), equipped with four transportation cylinders, was to launch four MTRs on the Spanish side of Algeciras Bay. The boats were to make their way along the neutral shore and, at 1100 hours, carry out a suicidal daylight attack on merchant shipping at Gibraltar. In the resultant confusion, it was hoped, a Pig launched from the secret base aboard the Olterra would penetrate the military harbour and attack the largest warship in sight. The operation was forestalled by Italy’s surrender on 8 September 1943.


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