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The Sinking of the Battleship Roma and the Dawn of the Age of Precision Guided Munitions

A couple of hours after midnight on the morning of Sept. 9, 1943, a large force of Italian warships – three battleships, three cruisers, and eight destroyers – slipped out of the northern Italian port of La Spezia. Leading them was the Roma, the Italian Navy’s newest and largest battleship, and they were going out to attack a large Allied naval force, which was, at that moment, staging an amphibious invasion further down the coast at Salerno. At least that was what Adm. Carlo Bergamini told a local German commander. But what they were really doing that night was switching sides and joining the Allies.

Roma was a beautiful, capable warship, and perhaps in other circumstances her role in history might have been a gallant or even decisive one. But instead, it was limited to a single, brief appearance as a sort of sacrificial lamb, slaughtered at the altar of a horrible new kind of weapon.

Roma was a beautiful ship, but then, building beautiful warships was something the Italians were known for. She was trim, and graceful, unlike, say, British warships, which tended to be blocky, purposeful, and businesslike. But the Roma was not just pleasing to the eye, she was also well-armored, fast moving, and very capably armed with three main gun turrets, two forward and one aft, each mounting three 15-inch guns that could fire a high-velocity, armor-piercing shell more than 25 miles. Roma was built to withstand incoming shells, and its compartmented hull, with its ingenious system of bulkheads and expansion cylinders, was made to withstand enemy torpedoes.

The Italian battleship Roma was considered to be a beautiful ship in keeping with Italian naval design. Italian Navy photo

The Italian battleship Roma was considered to be a beautiful ship in keeping with Italian naval design. Italian Navy photo

Roma was a beautiful, capable warship, and perhaps in other circumstances her role in history might have been a gallant or even decisive one. But instead, it was limited to a single, brief appearance as a sort of sacrificial lamb, slaughtered at the altar of a horrible new kind of weapon.

By this point, the war was going very badly for Italy and they wanted out. Mussolini had already been deposed and arrested two months earlier, and even though his successor, Prime Minister Badoglio, continued to openly profess solidarity with Adolf Hitler, he quickly started secret negotiations with Allied supreme commander Gen. Dwight D. Eisenhower.

The most warlike thing Roma had done was serve as a floating anti-aircraft battery during air raids while tied up in La Spezia.

At the beginning of September, a secret “short” armistice was signed between representatives of Badoglio and Eisenhower, which, among other things, called for handing over the Italian fleet to the Allies at Malta. Over the next several days, the navy’s commanders were told to make preparations for getting under way, though none except for Bergamini and one or two others were told the actual reason why. The fleet got ready, but there were repeated delays and postponements. Then, on Sept. 8, just as they were beginning their invasion of Salerno, the Allies announced the armistice from a radio station in Algiers. The cat was out of the bag, and Italy was plunged into chaos. A few hours later, Bergamini boarded the Roma and gave the order to cast off and head for the open sea.

For the Roma, this marked her first actual foray out since joining the fleet a year earlier. During that time, Roma had clocked only about 130 hours under way, and all while repositioning from one port to another. The other warships had taken part in some naval actions earlier in the war, but for the last two years it had been the same story for them as well. Italy had been suffering from a major fuel shortage. Not having any native source of petroleum, Italy depended on Germany for fuel, and Germany wasn’t exactly flush either. The most warlike thing Roma had done was serve as a floating anti-aircraft battery during air raids while tied up in La Spezia. Twice during that time, she’d been severely damaged after being hit by large bombs dropped from American B-17s. She’d had to be towed to Genoa for repairs.

The Italian battleship Roma at anchor. The Roma was sunk on Sept. 9, 1943. Italian Navy photo

The Italian battleship Roma at anchor. The Roma was sunk on Sept. 9, 1943. Italian Navy photo

The armistice agreement directed the Navy to go to Malta and surrender the ships there. However, Bergamini had a different plan. He was taking his fleet to La Maddelena on Sardinia, where King Victor Emmanuel III was setting up a “free government” favorable to the Allies. Eisenhower had apparently given his approval and allowed the transfer of one Italian destroyer there to be placed at the King’s disposal. Bergamini decided it might be a better idea to move the whole fleet there and let the monarch take his pick.

Once in the open sea, the fleet was joined by three cruisers from Genoa. The flotilla steamed through the rest of the night, making good speed and keeping about fifteen miles off the west coast of Corsica. At dawn they spotted an allied aircraft shadowing them. Bergamini took it as a good sign.

No one bombed ships from heights like that, not if they wanted to actually hit it. Besides, they estimated that instead of releasing their bombs at an 80-degree angle, as was normally done, they had released them at a 60-degree angle. It didn’t make any sense. Why had they done that?

At 1200, the Italian fleet, traveling in line astern formation, made its first sighting of the Strait of Bonifacio, the four-and-a-half-mile gap separating Corsica from Sardinia. Bergamini ordered a 90-degree turn toward La Maddelena. At 1340 they received news that the Germans had seized La Maddelena. Bergamini immediately ordered the fleet to reverse course 180 degrees and head to Malta. By 1400, the fleet was in sight of the Asinara, a rocky, mountainous island off the northwestern tip of Sardinia. Beyond it lay the western Mediterranean.

Then the lookouts spotted aircraft shadowing them. They were twin-engine aircraft, but flying at high altitude, and no one could tell for sure whether they were Allied or Luftwaffe. To the Italians’ surprise, they dropped bombs. But the bombs came down into the water, far from any other ships. As soon as they had, they turned and left. Everyone was bewildered. No one bombed ships from heights like that, not if they wanted to actually hit it. Besides, they estimated that instead of releasing their bombs at an 80-degree angle, as was normally done, they had released them at a 60-degree angle. It didn’t make any sense. Why had they done that? Could it be that they weren’t actually trying to hit them?

A German Fritz-X Guided Bomb in the World War II Gallery at the National Museum of the U.S. Air Force. U.S. Air Force photo

A German Fritz-X Guided Bomb in the World War II Gallery at the National Museum of the U.S. Air Force. U.S. Air Force photo

More than an hour passed and nothing happened. Asinara Island was much closer now. Then the lookouts reported that the twin-engine aircraft were back. The lookouts identified them as German Dornier Do 217 medium bombers. Each seemed to be carrying a single, very large bomb under the wing in the space between the starboard engine and fuselage.

At 1530, the aircraft climbed from 5,000 up to 5,500 meters (18,044 feet) and then began closing in on the fleet. Bergamini ordered the ships to begin evasive maneuvers and told the AA batteries to open fire. A moment later the ships’ anti-aircraft guns started shooting, but the bombers were too high up to hit.

The bomber released its bomb and maintained its position as the bomb hurtled downward at them. Sure enough, as it came in, it became sickeningly obvious that the bomb was being steered to the target.

At 1533 the first aircraft attacked. It dropped its bomb at the same 60-degree angle as the earlier one had. But as it came down, they noticed that instead of simply falling downward, it came at them as if it were being steered. It splashed into the water, narrowly missing the stern of the battleship Italia by just a few feet. Then it exploded. A few seconds later, the Italia reported that the explosion had jammed its rudder and that it could no longer steer.

Tense minutes passed as the repair crews aboard the Italia struggled to free the rudder. While they did, messages traveled back and forth between the ships about what had happened. Several of the lookouts reported that the bomb seemed to have four long wing-like fins and a boxlike tail. Someone noted that instead of peeling off once the bomb had been released, the Dornier remained in place, flying slowly, as if it needed to stay there to guide the bomb in.

The Italian battleship Roma in her death throes, Sept. 9, 1943. Italian Navy photo

The Italian battleship Roma in her death throes, Sept. 9, 1943. Italian Navy photo

At 1545 there was another attack. The AA batteries opened fire, but again the bomber was beyond the range of their guns. The Do 217 released its bomb and maintained its position as the bomb hurtled downward toward the Italian fleet. Sure enough, as it came in, it became sickeningly obvious that the bomb was being steered to the target.

The bomb struck Roma on its starboard side aft of amidships, crashing through the ship’s seven decks, and exited the hull before exploding beneath the keel. The boiler rooms and after engine room flooded, disabling the two inboard propellers. Electrical arcing started innumerable fires throughout the after portion of the ship. Her speed now reduced to 12 knots, the Roma fell out of the battle group. By now, many of the ship’s electrically controlled systems, its directors and gun mounts were out.

What sent Roma to the bottom was the first of a wholly new class of weapon, known today as precision guided munitions (PGM). This PGM in particular was a massive 3,450-pound, armor-piercing, radio-controlled, glide bomb, which the Luftwaffe called Fritz-X.

At 1552, Roma was hit by a second bomb, again on the starboard side, this time detonating inside the forward engine room. The forward magazine detonated. There was heavy flooding in the magazines of main battery turret No. 2 as well as the forward portside secondary battery turret. A few moments later the No. 2 turret’s magazines exploded, blowing the entire turret skyward. The forward superstructure was destroyed with it, killing Bergamini, the ship’s captain, Adone Del Cima, and nearly everyone else there. Fires had broken out all over the ship. Whoever wasn’t killed was burned horribly. At 1612, Roma began going down, bow first. Then, her starboard decks awash, the Roma capsized, broke in two and sank. By 1615, she was gone, with 1,253 of her crew of 1,849 officers and men dead.

What sent Roma to the bottom was the first of a wholly new class of weapon, known today as precision guided munitions (PGM). This PGM in particular was a massive 3,450-pound, armor-piercing, radio-controlled, glide bomb, which the Luftwaffe called Fritz-X. It had been developed on the tails of the Hs 294, a more complex, but somewhat less effective, winged rocket, also deployed from a D0 217 bomber. Unbeknownst to almost everyone, the Hs 293 had already made its debut two weeks earlier, when it sank one British warship and seriously damaged two others in the Bay of Biscay.

A trial drop of a Fritz-X radio-controlled bomb. Fritz-X bombs were responsible for the sinking of the Roma. Bundesarchive photo

A trial drop of a Fritz-X radio-controlled bomb. Fritz-X bombs were responsible for the sinking of the Roma. Bundesarchive photo

Unlike the Hs 293, which combined a compressed-air injection system with a binary-fuel rocket motor, Fritz-X was a simple system. To reach its target, Fritz-X mainly needed gravity. Dropped from 6,000 meters, Fritz-X came in at a nearly transsonic velocity, which is why it could go right through so many layers of deck and armor before exploding, something the Hs 293 could not do.

Fritz-X consisted of an 11-foot-long, machined steel penetrator casing, loaded with 320 kilograms of impact-fuzed amatol explosive. The bomb had four centrally mounted fins and a complex, boxlike tail structure, inside of which was a set of radio-controlled, electrically operated, oscillating spoilers that provided pitch and yaw control. Though the Fritz-X used the same radio-link receiver guidance package as the Hs 293, its control package included a gyroscope to provide roll stabilization. This was necessary, since it received controlling signals through a conformal antenna built into the tail section. The gyro ensured that the Fritz-X’s tail remained pointed at the aircraft throughout the drop.

Then, her starboard decks awash, the Roma capsized, broke in two and sank By 1615, she was gone, with 1,253 of her crew of 1,849 officers and men dead.

Guiding the Fritz-X was relatively simple. Upon release, a flare ignited in the bomb’s tail. Looking through the bombsight, the bombardier would simply line up the flare with the target, using a dual-axis, single joystick-equipped radio controller. After that, it was just a question of keeping the two lined up with each other.

For the next week, the Fritz-X repeatedly wreaked havoc at Salerno. Its first victim was the cruiser USS Savannah, which suffered more than two hundred dead when one of the glide bombs smashed into a gun turret. After that came the cruiser USS Philadelphia, followed by the Royal Navy‘s HMS Uganda, then several merchant ships and finally the British battleship Warspite. In each case, the ships were put out of action for up to a year, though all eventually went back into action. But as terrible as the damage was, it wasn’t enough to turn back the invasion.

The USS Savannah (CL 42) is hit by a German radio-controlled bomb, while supporting Allied forces ashore during the Salerno operation, Sept. 11, 1943. The bomb hit the top of the ship's number three gun turret and penetrated deep into her hull before exploding. This photograph shows the explosion venting through the top of the turret and also through Savannah's hull below the waterline. A PT boat is passing by in the foreground. U.S. Naval Historical Center photo

The USS Savannah (CL 42) is hit by a German Fritz-X radio-controlled bomb while supporting Allied forces ashore during the Salerno operation, Sept. 11, 1943. The bomb hit the top of the ship’s number three gun turret and penetrated deep into her hull before exploding. This photograph shows the explosion venting through the top of the turret and also through Savannah’s hull below the waterline. A PT boat is passing by in the foreground. U.S. Naval Historical Center photo

The new weapons’ reign of terror also turned out to be short lived. As devastatingly effective as the Fritz-X and the Hs 293 might have been, they had two weaknesses. The first, the Allies figured out almost immediately: Once the Fritz-X had been dropped and started falling toward its target, the bomber needed to fly straight, level, and slow in order to guide it in. As long as the skies were uncontested, then there wasn’t a problem, but if there were any Allied fighters around, then the bomber could be easily shot down during this phase.

While none proved effective enough to allow the Germans to resume their guided bomb offensive, it did mark the beginning of a battle of measures and countermeasures, which today, 70-odd years later, shows no sign of abating.

At the same time, the British and Americans began developing electronic countermeasures to jam the radio link between the bomber and the bomb. The first Allied jammer proved ineffective, since it jammed the wrong frequencies. But subsequent improvements began to close the gap, which markedly reduced the effectiveness of the Fritz-X and Hs 293. Then an intact Hs 293 was discovered at a captured airfield up the beach from Anzio. Shortly after that, one of the radio control transmitters was recovered from a German bomber that had crashed on Corsica. The jammer developed as a result proved highly effective. By that point the Luftwaffe was already developing new variants of the two weapons that would be resistant to jamming. While none proved effective enough to allow the Germans to resume their guided bomb offensive, it did mark the beginning of a battle of measures and countermeasures, which today, 70-odd years later, shows no sign of abating.

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Brendan McNally is a journalist and writer specializing in defense and aerospace. Brendan began his career...