The Frogmen Attack

The exploits of midget assault craft in World War II provided what is unquestionably the brightest chapter in Italy’s naval annals. Slow-speed torpedoes nicknamedpigs,each operated by a crew of two men, sank the British battleship H.M.S. Valiant and blew up the British battleship Queen Elizabeth inside the port of Alexandria. Despite all precautions of the British Mediterranean Fleet, the Italian frogmen sank or damaged, all told, four warships and twenty-six merchant ships. COMMANDER LUIGI DURAND DE LA PENNE participated in a successful assault on Gibraltar before engaging in the sinking of the Valiant. His personal recollections he confided to a good friend, Captain Virgilio Spigai, an Italian submarine skipper. The following article is taken from his account as it appeared in the February issue of the United States Naval Institute Proceedings.




WE LEFT Rome by plane on December 12, 1941. There were three regular two-man crews and two additional reserve crews, making a total of ten men in all assigned to carry out the mission of attacking the British Fleet at Alexandria. Each human torpedo was to be manned by a commanding officer, seated forward at the controls, assisted by one diver, seated aft, whose principal responsibility was to help in the final and most strenuous part of the enterprise — the attaching of the warhead to the keel of the enemy warship.

Every branch of the officer corps was represented.

I (de la Penne), the officer in charge of the assault crews, was a line officer; Antonio Marceglia was a naval engineer; Vincenzo Martellotta was a member of the construction corps. In the reserve crews were Sub-Lieutenant Luigi Feltrinelli, a line officer, and Surgeon Midshipman Giorgio Spaccarelli, a medical officer. The officers, all trained divers, were assisted by the following qualified deep-sea divers: Emilio Bianchi, Mario Marino, Spartaco Schergat, Armando Memoli, and Luciano Savare.

In addition to being volunteers, these officers and ratings were men of exceptional physique and endurance. Despite gaps left in our ranks by those who lost their lives or were taken prisoners during these actions, a great number of volunteers could be found right up to the end of the war.

Among the members of the assault crews there was complete awareness of the difficulties of the impending operation and the risks about to be undertaken. Nevertheless, a very cheerful spirit was evident in the group. We knew that we were going to the submarine base at Leros in the Aegean Islands, on the island of Rhodes. There we would board the submarine Sciré and be transported to a point off the harbor defenses at Alexandria where we would don our diving suits, go out on deck and, while the submarine was submerged, launch our “pigs,” get astride them, and somehow enter the harbor of Alexandria. On arrival in the midst of the British Fleet, and while it was still completely dark, we would attach the warheads to the bilge keels of the most important targets. What would happen to us upon completion of the assignment interested us only up to a point. If we were lucky, it might mean imprisonment for the duration of the war; if unlucky, it meant death. Being very young, none of us believed the worst would happen.

We reached Leros and proceeded to the submarine base, where we found the Sciré ready and waiting to take us to Alexandria. This submarine was specially equipped to carry human torpedoes. Cylindrical caissons had been mounted on deck from which the torpedoes could be launched submerged.

Obviously, to command a submarine of this type an officer of remarkable ability was needed. Such a person was found in Lieutenant Commander Principe Iunio Valerio Borghese, who had twice entered the Bay of Gibraltar, dropping off assault craft without the British being aware of it. At an earlier date some of our submarines had tried similar operations, and two of them, the Iride and the Gondar, were sunk before reaching Alexandria. The main operative difficulty in the Eastern Mediterranean was the extreme clearness of the waters and the lack of depth close to Alexandria.

Copyright 1956 by the United States Naval Institute, all rights reserved.

The assignment had been accurately worked out. It had been decided that we should move from Leros with the Sciré as soon as weather conditions, the moon, air reconnaissance observations, and the naval situation at Alexandria made it seem possible that the expedition could be undertaken against a target commensurate with our risks. We had complete faith in our “chariots” and in the submarine Sciré. We also had confidence in Commander Borghese and, of course, in ourselves.

The most trying thing about these operations is the waiting, but we were favored by Commander Borghese’s decision to leave immediately. Hence, after removing the camouflage from the submarine which concealed it from air reconnaissance, we left Leros on December 14. We had to cross the Eastern Mediterranean submerged and at the same time avoid such obstacles as enemy air reconnaissance, naval visual reconnaissance, the minefields outside Alexandria, the electric antisubmarine mines and hydrophone signals, and finally radar indicators. It was these radar indicators which had been the reason for our unsuccessful attempt to break through to Malta four months earlier.

But all these difficulties were the submarine commander’s worries, not ours. While the submarine advanced slowly and carefully toward its goal, we passed the time as best we could — reading, writ ing, and drinking enormous quantities of fruit juices. The Sciré was perfectly silent and had good airconditioning and other characteristics which helped us to endure the journey fairly well in spite of the rough seas which aided Commander Borghese in avoiding the network of vigilance and in bringing the submarine to rest, earlier than anticipated, on the bottom at a point 45 feet in depth, 1.3 miles north of the lighthouse on the pier west of the commercial port of Alexandria.

Before submerging, the Sciré received from Athens reports of the afternoon reconnaissance by the Italian Air Force from the Egec air base. They reported many ships in the harbor of Alexandria, including two battleships of the Queen Elizabeth class. Although our enterprise had hardly begun, we felt a quiver of enthusiasm, as though the sinkings had already taken place.


REGULATIONS prescribed that the commanding officer of the submarine have full command of the expedition up to the point of launching the assault craft from the submarine, It was his responsibility to select the targets and designate the attackers.

His assignments were as follows: —

To the chief of the expedition (myself) and chief diver Bianchi, the first battleship. To Lieutenant Marceglia and diver Corporal Schergat, the second battleship. To the third crew, Lieutenant Martellotta and chief diver Marino, the following orders were given: “ Check if there are any aircraft carriers in port. If no aircraft carrier is present, give up the idea of attacking smaller warships.” This order implied that priority was to be given to tankers before cruisers. Tankers were given priority over cruisers in order to assist us in our secondary objective of setting fire to the fuel oil which would inevitably cover the surface of the water after the explosions.

Two reserve crews, under Sub-Lieutenant Feltrinelli and Midshipman Spaccarelli, were given orders to leave the submarine and assist the regular assault crews in taking the craft out of the caissons where they had been stored during the submarine’s journey.

While these orders were being given out, we struggled into our assault kits. In the humidity and heat of the submarine it was quite a job to get into these special black rubber suits, which were perfectly airtight and perspiration-proof, and as oppressive as the strangle hold of a wrestler.

After we had dressed and put on our respirators and luminous, waterproof wrist watches, Commander Borghese ordered the Sciré to surface. Having given us his customary kick in the pants for luck, he sent us one by one up the vertical ladder in the escape hatch and we climbed out into the open air. The night was beautiful and still, and in the mild weather under the stars it seemed as though the war were a myth. Unfortunately, this illusion did not last long.

The submarine submerged with us on deck, and we began our work of taking the craft out of the caissons preparatory to leaving in formation for the entrance to the port.

Our SLC (slow-speed torpedo) assault craft units (which we called “pigs” or “chariots”) were barely 20 feet long and had an overall height of about 3½ feet. They were powered by electric storage batteries. Fore and aft and amidships, small buoyancy tanks similar to those on submarines were placed for submerging and surfacing, with electric pumps for trimming. The speed of an SLC was just over 2 knots, and its cruising radius was 10 miles. To maneuver this seagoing automobile, we had to sit astride and work controls very much like those of an aircraft. The instrument panel with its luminous dials was similar to that of a plane. It contained a magnetic compass, a depth gauge, a manometer for registering pressure in the tanks, a voltmeter for the control of the batteries, an ammeter, and a spirit level for reading the angle to the horizontal.

The torpedo was equipped with a warhead which could be detached without interfering with the operation of the craft. This had been done purposely so as to allow the operators to approach a ship, fix the charge in position, and get away. The charge was fitted with a time fuse. In addition, the assault craft itself was fitted with a self-destructive device which could be used when necessary to avoid its falling into the hands of the enemy. Ordinarily in such cases the operator set the selfdestructor, locked the controls on full dive, sent the torpedo to the bottom where it destroyed itself, and then swam ashore following the attack.

The craft were tested for a depth of 100 feet and had been adjusted with infinite patience according to the results of exhaustive trials carried out at the La Spezia naval base and on the beach of the royal estate at San Rossore near Pisa. As a result of the trials in combat during the expeditions on Gibraltar and Malta (which cost the life of the assault craft’s inventor, Captain Tesseo Tesi, Naval Engineer, and the imprisonment of his collaborator, Lieutenant Elios Toschi) we had confidence in the readiness of our craft.

Each craft was equipped with a full set of tools and instruments and was fitted with compressedair net lifters and net cutters, heavy shears, clamps for the ship’s bilge keel (we call them “sergeants”), and a crude sort of safety line called a “lift” which consisted of a rope tied to the operator and of sufficient length to permit him to leave his saddle, rise vertically from the craft, and return.

To attack a ship, one had to execute the following maneuvers: —

1. Approach on the surface with only the operator’s head out of water until about 150 feet abeam of the target.

2. Submerge and approach until the operator could touch the ship’s hull with his hands.

3. Proceed gently, feeling the ship’s bottom by hand, until locating the bilge keel on the near side.

4. Fix a clamp on the bilge keel and secure it to the warhead with a line.

5. Continue all the way under the ship and secure the second clamp on the opposite bilge keel.

6. Secure the rope to the second clamp and stretch tightly.

7. Cast the warhead loose and move it along the line until it was suspended directly below the center line of the ship.

8. Set the time fuse.

9. Cast off and proceed to a point well clear of the ship.

The operator then set the self-destructor and tried to make good his escape. When the charge exploded directly under the ship’s keel, it hit the ship in its most vulnerable and least protected spot.

It should be mentioned that before arriving at a ship, the operator usually had to pass through the boom defenses of the harbor. This he did by approaching along the bottom and lifting the net, or by approaching the net at a point where it could be cut with the compressed-air shears carried for that specific purpose. During both of these operations, he hoped not to set off any of the explosives which were frequently to be found on the nets. After entering the harbor, the operator still had to proceed undetected to a point within the torpedo nets which were always placed around ships at anchor.

As a result of our experience during many training tests and expeditions, we had learned that the worst obstacle to success was not the enemy’s lookout but the extreme cold, which, as time went by, took hold of us in a vise-like grip. Damage to equipment was also a constant and serious hazard. Rips inevitably occurred in the rubber diving suits during work, and permitted the entry of cold water. The respirators, too, might fail. Any one of a number of small hitches of this kind might interrupt an operation which represented many months of preparation. We had spent many months of training in cold water at night to get accustomed to the cold and to the dark. This we found useful only up to a point — beyond which, in cold-water operations, the operator had no alternative but to accept the hardship imposed by the cold. Experience had taught us that best results could be had by using bare hands. Finally, since our oxygen-filled respirators were good for only five or six hours, the whole operation had to be carried out within that limitation.


HERE is what happened that memorable night outside the harbor of Alexandria. We were delayed in leaving the submarine because one of the SLC storage cylinder hatches wouldn’t open. During this perilous operation, Surgeon Spaccarelli nearly lost his life. As it turned out later, he fainted from oxygen poisoning induced by exertion and fell to the deck of the submarine — fortunately without sliding off into the mud on which the submarine was resting. He remained thus for nearly half an hour, and only by very good fortune was he discovered by his friend, Feltrinelli, who brought him back inside the submarine where he was finally revived.

Our attack group left about 9 P.M., and the submarine, having finished her role, departed and returned uneventfully to Leros.

Upon launching our “chariots” from the submarine, the three of us proceeded in formation on the surface toward the harbor. I was in the center, Marceglia on my left, Martellotta on the right. During the run in we proceeded without respirators, with our heads out of water. Two hours later we were abreast of Ras El Tin lighthouse and, to our surprise, arrived there considerably ahead of schedule. We therefore lay to, broke out our emergency rations, and had something to eat. The cold and the fresh air had given us a terrific appetite, and we felt it necessary to eat in order to be in top shape when we neared the targets. Although the light in the lighthouse was out, the weather was so fine that we could see the structure.

Everything thus far had progressed as smooth as oil. Then, while we were eating, the lighthouse of Ras El Tin suddenly lighted up. At this time we were only 500 yards from it. So, very cautiously and very slowly, we moved farther away so as not to be seen. I decided to move at once toward the mouth of the harbor, which was some distance away, but of whose location I was now sure. At about midnight we heard — and felt — sharp underwater explosions which painfully constricted our legs, the only part of us under water. We rounded the south jetty by dead reckoning at minimum speed, keeping station on one another and with only the head of the forward pilot of each “ chariot ” above water.

We now found ourselves before the outer boom defense, which was patrolled by a large motorboat cruising back and forth and dropping occasional depth charges. Between the explosions it was very quiet, and we could hear a few men talking on the pier; in fact, we were so close that we noticed one of them carried a lantern in his hand. The periodic explosion of the depth charges was very annoying to the pilot, whose legs continued to receive the shock of each explosion. But far worse was the effect of these explosions on the number two pilot, who during this period had put on his respirator and ducked down so as to be completely submerged, He, of course, received the full jolt from each explosion.

Suddenly we saw signal lights showing at the gate of the boom. This meant that ships were about to enter the harbor. I decided to attempt to run in with the entering ships through the open gate rather than attempt to go under or through the net. We therefore proceeded to a position near an obstruction buoy hard by the gate.

Soon the lights on this buoy went on, and I had a glimpse of dark shapes rapidly approaching. This meant the gate was open. As it turned out, the shapes were three large British destroyers. Cautiously, I submerged and moved forward, and as I passed in the gate, the destroyer passed at what seemed like just a few inches over my head. Fortunately the surge from her bow forced me down, where I touched bottom — happy, indeed, to have missed the screws. As soon as I hit the bottom, I put on full speed, entered the harbor with the second destroyer, and then came up to the surface. By this time the third destrover,which had followed closely behind, had entered, and it created a bow wave which hurled me against the inner obstruction buoy— luckily without serious effects. Since I had now entered the harbor, this small mishap did not worry me.

During this time, I had lost contact with my friends. This had been anticipated in the instructions, and so I made no effort to contact them but proceeded on toward my target with only my head showing above water. The third destroyer had stopped near me, her crew on deck preparing to anchor. I changed course, passed her astern, and steered over toward the northern inner breakwater and away from the quay so as to avoid the lights from land. En route to my objective, I passed two enemy cruisers moored stern to shore. I passed across their bows and under the stern of the French battleship Lorraine, which was moored near enough to the British battleship I was seeking so that as I passed beyond her I at last caught sight of my target. She was enormous — a 31,000-ton battleship. I was thrilled by the thought that the strength and daring of only two men were to cripple her.


A THOUSAND yards of fairly well lighted water separated us at this time, and across this stretch I slowly made my way with only my head showing. In this attitude I came up against the torpedo nets which surrounded the ship. I realized that I could not get through this obstruction without breaking surface with my whole assault craft. I dismounted into the water and, joined by my other operator,

I pushed the “chariot” between two spherical floats. We simply could not avoid making some noise, but happily no one noticed us. During this operation my diving suit was punctured, and it immediately flooded. The intense cold bit into me with icy fingers.

I was now within 100 feet of the side of the battleship, with no obstruction in front. It was

2 A.M. on December 19, 1941. My present position was the result of six years of study and strenuous training. For a moment it seemed almost insignificant and hardly worth the effort. This fleeting thought departed as I put on my respirator, which I had not used during the approach to the battleship. I submerged to 20 feet and steered by compass on the bearing of the ship’s funnel. This, L expected, would put me amidships.

In a few moments I struck against the hull but could not operate the controls to stop my motor because by now my hands were numb with cold. Out of control, my “chariot" suddenly became heavy and went to the bottom at 50 feet. I left the assault craft and swam up to the surface to cheek my position. I could see that I was about 45 feet forward of the number one stack. I then submerged, and followed my lift rope back to the “chariot,” where I found to my unpleasant surprise that my number two man, Bianchi, was missing and my motor refused to turn over.

Again I returned to the surface, but could find no sign of Bianchi. On board the enemy battleship everything was quiet. On my next trip down I found that a steel cable had wrapped itself tightly around the propeller of my “chariot.” I realized the motor would never move again, and I thereupon decided the only thing to do was to drag the torpedo along in the mud by main strength until it was directly beneath the ship. The mud was extremely gooey and cut out all visibility, but I guided my “pig” by the noise of one of the pumps on board the enemy ship.

The frightful effort made me sweat as if I were in a Turkish bath. Sea water seeped into my mask, and I had to drink it to avoid drowning. Although I was submerged in water and was drinking all the time, I had a continuous sensation of terrible thirst. After what must have been about a twentyminute struggle, I noticed the noise of the pump becoming louder. I rested a moment and managed at last to check my heading by my compass and insure that I was going in the right direction. At the same time, the depth was gradually decreasing, showing that I was slowly approaching the ship’s hull.

After about twenty more minutes, with increasingly longer periods of rest, for my strength was fast giving out, I hit the hull of the ship with my head. At last I had arrived! I was nearly exhausted.

I checked my bearings, dragged the torpedo under the center line of the ship, attached the warhead, and set the fuses. I did not bother to set the clamps tight because by now I had no doubts as to our success. At the appointed time, everything would be blown up as planned — the ship, and the assault craft as well. Since its location on the bottom was so near the hull of the ship, the explosion would destroy both.

I floated up to the surface and took off my respirator. As I was swimming away, someone on the battleship’s deck almost over me saw me and ordered me to stop. I paid no attention and kept on swimming until a hail of machine-gun bullets induced me to change my mind. I headed for the ship’s mooring buoy, where to my great joy I discovered Bianchi. He had been overcome underwater but had revived when afloat, and with great intelligence, so as not to interrupt the operations or give the alarm, had swum slowly over and hid himself behind the mooring buoy. I reported that everything had been accomplished, but at that very moment I nearly lost my own life through stupidity. As the British were shouting at us from the bow of the ship, I thought to go on board by climbing up the anchor chain. But another deadly hail of machine-gun fire made me realize that I had better stay where I was. It was now three-thirty in the morning as Bianchi and I perched prudently on the buoy, awaiting developments.

After a while a boat came by to pick us up, and we were taken on board the British battleship. I handed in my identification papers, and at first was treated rather roughly, although not violently. I declined to give any information and smiled inwardly as the officer who made the cross-examination sympathized with me for the failure of our mission. Then we were taken by motorboat to Ras El Tin and questioned in Italian by other officers. Bianchi and I maintained our stubborn silence, although we were told they would find a way to make us talk.

After this we were taken back aboard the battleship and down into the forward hold between the two gun turrets. The men on guard were kind and generously offered us rum and cigarettes. Still aching with cold after my long immersion, I reflected on my future at this point. What would happen in this deep hold during the explosion? Would we die by drowning or be blown to bits? Bianchi didn’t seem to be worried by this dubious choice and fell asleep. With deep satisfaction I noted that the ribbon on the sailor’s cap said H.M.S. Valiant. Whatever happened to me, I could feel proud that I had fulfilled my mission to the letter. I had not failed my country.

Meanwhile, day was breaking. This meant only ten minutes were left before the explosion. I asked to be taken to the ship’s captain and warned him to give orders to abandon ship and save the personnel, for the ship would be blown up within a few minutes. He still tried to get me to talk, but receiving no reply he had me sent back to the hold as the loudspeakers gave the orders I had suggested. So it was that I was deep down in the hold when the explosion occurred. But destiny did not intend that I should die at that moment.

The blast shook the vessel with extreme violence, the lights went off, and the hold was filled with smoke. But except for a pain in my knee, I was unhurt. The ship rapidly heeled over to port about five degrees and started to rest on the bottom. Groping my way up the ladder and through the open hatch to the upper bridge, I went toward the stern, where a number of officers were standing. They were watching the Queen Elizabeth, sister ship of the Valiant, which was anchored a hundred yards away from us. At that moment she too gave a terrific heave and blew up, belching scrap from her funnel and flooding the stern of the Valiant with gasoline. Then I knew that the brave efforts of Marceglia and Schergat had also met with entire success!

Once more Bianchi and I were taken down to the hold to see if we could be forced into giving information about possible further explosions; but when they decided it was useless to try to make us talk, they took us back to Ras El Tin, where we became official prisoners of war. That completes the story of my adventures on that memorable evening.


SINCE my story is only part of the mission so spectacularly accomplished, I must outline briefly what happened to the other two crews, my companions in this adventure.

It was not quite four-thirty in the morning, but still very dark, when Marceglia and Schergat got away from the Elizabeth. The enterprise had been carried out to perfection and without notable incidents. Marceglia and Schergat sank their craft with its self-destructive device set and got ashore safely on the beach.

When it was daylight, they managed to avoid the port patrol and made their way to a bar in Alexandria by posing as French sailors. But here an unpleasant surprise awaited them — the money they had was British and did not circulate in Egypt. To change a small amount, they lost precious time and attracted the attention of the police. However, they did get as far as Rosetta, where 10 miles off the coast the Italian submarine Saffiro was waiting for them. But the next day, just as they were about to reach the sea and freedom, they were arrested by the Egyptian police, recognized as Italians, and handed over to the British.

Actually they had been lost by the stupid oversight concerning the question of money, and by their own lack of experience. Perhaps their first step should not have been taken toward the sea, but toward a religious institution, where they might have found sanctuary until the search had subsided.

The third assault craft, commanded by Lieutenant Martellotta, also carried out its mission. He went in search of a tanker as per orders, and located a large tanker of 16,000 tons, moored in front of the fuel pier. Martellotta was overtaken by violent attacks of vomiting during the last part of the route; so it was impossible for him to use the respirator. Having reached the rudder of the tanker, he gave the diver orders to attach the charge under the keel anywhere, because it was impossible for one man alone to put the charge in the exact middle of the ship. This was done; however, the results were none the less effective, for at the given time a terrific explosion blew off the entire stern of the tanker. In addition Martellotta had set incendiary charges, but contrary to our expectations they did not ignite the oil spreading over the surface, and the harbor of Alexandria was saved.

Having conscientiously planted all the incendiary bombs, they sank their craft with its self-destructive device set and were able to land at the harbor coal pier and even get rid of their kit. Unfortunately, they were later caught and arrested while leaving the port, and were taken prisoners.

The Alexandria venture was neither the first nor the last attack made by the Italian assault craft of the Tenth Light Flotilla during World War II, but it was the most successful. At the cost to us of only six men captured, Great Britain was deprived of her last two battleships in the Mediterranean, as well as a large tanker, and her strategic position there was then completely reversed. For the first — and last — time in the course of the war, the Italian Navy achieved superiority and was able to dominate the Mediterranean until other operations again reversed the situation.