il recupero della "Leonardo da Vinci"

On the night of August 2, 1916, a tremendous explosion awakened the town of Taranto. At the navy anchorage, searchlights illuminated the stricken Leonardo da Vinci, the newest battleship in the Italian fleet, which was belching smoke and flames. A main magazine had exploded, blowing a hole through the ship from keel to main deck. Damage control efforts started immediately, but the ship was doomed. She lurched over, dumping survivors off her decks into the bay, and then quickly sank upside-down, taking 249 men with her. She settled in 36 feet of water, with part of her keel showing above the surface.

Searchlights and patrol boats searched the bay for an enemy submarine, while ship's boats rushed to rescue those in the water. But the search was in vain; no enemy submarine had dealt this blow. It was a time bomb, secretly placed in a powder magazine by saboteurs that had cost the Regina Marina so dearly. Eventually the trail was followed to the Austrian Consulate in Zurich, and a plot to destroy other Italian warships. Arrests were made, and two men were sentenced to death and one to life in prison for treason, though the life sentences were later commuted to life in prison.

The question of salvage came up immediately, as in addition to the obvious blow the national pride the sinking also deprived the Italians of a powerful warship costing the equivalent of over 4 million pounds. But the Italians lacked experience with marine salvage, and no one had ever tried an operation like this before: in addition to raising the vessel, she would also have to be righted.

Foreign salvage experts from Britain and the USA, including the most knowledgeable and experienced marine salvers in the world, descended on Taranto. They unanimously agreed: what the Italians proposed was impossible. They advised using explosives to break up the overturned ship, in an operation that would take tons of much-needed explosives away from the war effort, cost an estimated 100,000 pounds, and take months. But this operation would yield scrap metal, recover usable items from the ship, and would clear the harbor.

The Italians politely sent the 'experts' packing, for they were determined to achieve the impossible. The officers of the Italian Naval Engineering Corps began studying the problem, always with the goal of raising the vessel. Several plans were explored, such as the building a floating dock around the ship which, when pumped out, would raise the vessel, or the construction of a cofferdam around the ship so that repairs could be made where she lay. None were practical, due to the shortage of steel, the soft bottom, or other reasons. Others proposed rolling the ship over before attempting to raise it, but there was no way to move 24,000 tons of steel lying well off shore.

General Ferrati, chief Italian Naval Constructor, developed a plan to use compressed air to raise the vessel. Once afloat, the ship could be easily handled: She could then be towed to the Taranto drydock and repaired, and then re-floated and righted.

This brilliant plan was adopted immediately.

Divers had meanwhile began to survey the wreck, and discovered some rather unusual things. The bottom was very soft and muddy, so the ship had settled deeply into the bottom until her main deck was even with the bottom. She continued to sink, burrowing more and more deeply into the mud, until most of the hull and the entire stern was buried. But due to the softness of the mud, the ship was intact, and the weight evenly distributed over the hull. Rather than her turrets, funnels, and superstructure being crushed, they simply pushed down into the mud until they hit a layer of hard clay some 30 feet down. But as the mud supported the weight, the funnels were not even crushed!

General Ferrati and his assistant, Major Gianelli, were not discouraged. They ordered the construction of large-scale models of the ship, complete with every detail of internal structure and equipment, no matter how small. In the same way that today's computer experts run mathematical simulations of a salvage operation, the officers carried out untold numbers of experiments to predict the behavior of the ship under different circumstances. These led to mathematical calculations, on which the entire operation was based.

A small part of the ship's keel was still above the surface, so huts were built on it for the salvers: they would make the ship their home. Platforms were built on the submerged keel, and more buildings were erected for equipment. By the spring of 1917, the workshops were ready, access holes were cut into the hull, and divers began their work.

Visibility was almost zero, as vast quantities of oil, rust, and silt clouded the water inside the wreck. But the divers, made familiar with the layout with the models, worked day after day on the dangerous task of removing nearly 1000 12-inch shells, 3000 4.7-inch shells, several torpedoes, and hundreds of tons of powder charges from the ship. The oil in the water proved a blessing, as it protected the shells from the seawater and allowed their return to service.

A power cable was laid over a mile and a half from the power station to the wreck. With electric power and lights, the divers working both inside and outside the wreck began drilling holes, so patches could be riveted and bolted on to cover the hull damage. During this stage one man was killed, the only fatality of the entire operation. A layer of rubber was fixed to the hole, and a metal patch bolted over each one. One by one the divers made a compartment watertight, compressed air was pumped in to force the water out, and the compartment was sealed. Once the outer hull was sealed, giant air compressors began to feed air into the hull. The air was trapped below the surface of the ocean, adding lift to the overturned hull. As more and more air was pumped into the hull, the water was forced down and out. The water was forced back 26 feet, allowing workers entering through an airlock to access the ship's stores and coal, which were removed to lighten the ship further.

By November of 1917, strange sounds were heard from the wreck, and workers began to feel the battleship begin to stir beneath them. While most of the ship was still stuck in the mud, the bow was beginning to show a slight inclination to float again: the operation was working, and the Italians knew that the ship would live again.

The oil once again became a problem, for as the water receded it left an oily film on everything, frustrating attempts to search out every little leak that might let air escape. But the salvers persevered, despite their oily, rusty, smelly, and damp working conditions beneath the waves.

Now that it was obvious that the hull could be floated, it was time to address another problem: upside down, the ship would draw at least 50 feet of water, and the drydock was only 40 feet deep. In addition, the water was only 40 feet deep, and it was a mile and a half from the wreck to the drydock. General Ferrati and Major Gianelli had a plan: they would cut away the funnels, superstructure, and turrets to reduce the ship's draft.

Critics of the operation were skeptical. The turrets and top hamper were buried in the mud, and it would not be possible to clear the mud away as fast as it flowed back into the holes. And if a way could be found to keep the mud away, the ship would collapse without the mud to support its weight. But Ferrati made no attempt to clear away the mud at all, instead using compressed air to force the water out of select compartments, which allowed the water in the barbettes to be forced back to some 56 feet below the surface of the water, 20 feet below the level of the mud outside. All through 1918, a team of 150 men worked to remove the turret retention clips, detach the masts, and cut away the funnels and superstructure from inside the overturned ship. These items would be left in the mud when the hull re-floated, and could be revered later. The barbettes were sealed with wooden timbers and rubber, as were the holes for the funnels and any other breaches of the ship's decks. Tons of cork was packed into compartments to add buoyancy and keep back the water and mud. By 1919, tests proved that the ship was nearly ready to rise.

Sadly, General Ferrati passed away, and thus did not get to witness the results of his brilliant ideas and computations.

Major Gianelli had 8 lifting pontoons brought in, each capable of lifting 350 tons. This would add 2800 tons of lifting power, enough to break the hull free from the mud at last. They were sunk, lashed onto the hull with strong cables by divers, and all was ready for the lift by June, 1919.

The ship still drew quite a bit of water, and the harbor is very shallow. Dredgers were brought in to clear away thousands of tons of mud, creating a deep channel stretching a mile and a half to the gates of the drydock. This operation took until September, as the dredging could not be done ahead of time lest the channel quickly be filled in by the action of the tides.

While the channel was being dredged, the drydock was prepared. As with any drydock, the chocks were designed to rest under the keel, which in turn supports the weight of the ship. But Leonardo da Vinci would be docked upside down, and her main deck was not designed to support the types of forces the keel normally took. So giant timbers, 15 inches square, were used to build up the bottom of the dock to different heights, to match the contours of the decks and support the ship evenly. Everything had to be perfect, or the weight of the vessel, pressing down at 225 pounds per square inch, would displace the timbers and the hull would buckle beyond repair under its own weight.

By September 17, 1919, all was ready. Air compressors forced water out of the hull and pontoons, while water was let into certain compartments to balance the hull. Very slowly, a little at a time, the keel began to rise up above the water. The bow rose, but the stern remained stubbornly stuck in the mud. But then the upward force of the air overcame the suction of the mud, and the ship popped nicely to the surface, leaving her turrets intact on the bottom, to be lifted later by pontoons and cranes.

Tugs took the ship in tow, and eased her very slowly down the channel. By nightfall, the vessel was at the sill of the drydock.

The next day she was maneuvered into the dock, and after two days of adjustments the water was slowly pumped out, and the ship gently came to rest on the timber structure. The Italians were halfway home.

Repairs to the hull took 15 months. Valves were installed to allow water to flood into one side of the ship; the Italians would simply flood her until she capsized a second time, thus restoring her to the upright position. 400 tons of solid ballast was added inside the ship near the keel, to help make her top-heavy. The damage of the explosion was repaired, and the decks braced and reinforced to withstand the strain of rolling the ship over. Many things could go horribly wrong: the ship could simply sink again, or it could roll too far and end up wrong-side up again, or the stress of the roll could warp the decks and hull past the point of repair. Nothing like this had ever been tried before, and success or failure rested on the calculations done from the model tests years before, by a man no longer alive.

The dredgers went back to work, scooping out a large basin in the bay, deep and wide enough to allow the ship to roll freely without fouling the bottom. In January 1921, all was ready.

The hull was towed out to the basin, and with the eyes of a hopeful nation upon them, the engineers began the process that would either restore the wounded giant, or kill her once and for all.

Salvers opened the sea valves, and water began to enter the starboard side of the hull as they made a hasty exit from the area. As the free-floating ship began to list in the right direction from some 800 tons of flooding, pumps forced water above the center of gravity so that she would overbalance and right herself. Calculations showed that some 7500 tons of water was needed, so the pumps continued their work as the hull began to settle deeper into the bay. The weight of water increased, and then the point of instability was reached. With a sudden rush, the ship flipped over, a large wave sweeping off her main deck as it broke the surface. She turned so suddenly, and with such force, that onlookers feared that she would continue her roll, finishing upside down again. But the calculations were perfect: the roll stopped, reversed itself, and when the rocking stopped the ship was right side up with a slight list, just as predicted. Across her deck, painted by workers before the upside down hull was floated out of drydock, was a quote from the ship's namesake: "Every wrong rights itself." The Italians had done the impossible, and turned tragedy into triumph.

The salvage took four and a half years, lost one worker his life, and cost the equivalent of 135,000 British pounds, not including the repairs to the ship. The hull was secured and pumped out, ready to be rebuilt. But economic conditions deteriorated quickly, and no money was appropriated to finish the repairs. The ship sat until March of 1923, when the vessel was officially stricken, and then cut up for scrap.


The raising and righting of the Leonardo da Vinci, though later overshadowed by the salvage efforts at Scapa Flow, ranks as one of the most spectacular salvage operations in history. Those raising the vessels of the High Seas Fleet, and by many salvers in the decades to follow would repeat the techniques used by the Italians.

The Leonardo da Vinci in 1911. It would take two years to refloat her after the fatal explosion.	The overturned hull, seen in a photo taken August 3, 1916. She has not yet begun to sink into the mud.
After refloating, the overturned hull is pushed into drydock in September 18, 1919.	By the next day the hull is properly braced, and the pontoons are being removed to drain the dock
September 21th: the drydock is drained, and the ship rests on timber framework.	Repairs are well under way in this undated photo, taken from an airship
The upside-down ship is towed out to be righted after repairs to the hull, January 22, 1921.	A large basin was dredged out to give the ship room to roll over without hitting the bottom.
With 400 tons of solid ballast to make her keel-heavy, water is let in to start her rolling over.	As the water weighs down the starboard side, the ship suddenly rolls herself upright.
"Every wrong rights itself," The ship is upright, with a list from the ballast water.	After pumping out the water, the ship will sit on an even keel, ready for a refit and a return to service.
The hull is level, being attended by a floating crane and an old sailing vessel turned barge.