scuba diving has always aroused curiosity, because knowing what is hidden under the sea is something that we all love. draws attention at some point in life. The seabed continues to host all kinds of marine mysteries and a practice with so many years of experience tells a fascinating story.
First uses of bells
After the discovery of America, the number of ships that set out to cross the Atlantic to reach the new continent increased. Around the year 1520, Fernando de Magellan was the first person who attempted to carry out a depth survey in the open sea after crossing the strait.
Upon reaching the Pacific Ocean (nicknamed by himself), he tied all the ropes he had on his boat and threw a plumb line into the water, thus verifying that the largest of the oceans was more than 180 meters deep.
Many ships were shipwrecked, due to the weather and battles, in the coastal waters of the numerous islands of the current Caribbean. Some ships were sent from Europe to the sinking area with the intention of recovering part of the cargo. By using the various bells, divers tried to recover cannons, precious metals and any valuable remains of the cargo.
Meanwhile in Europe, with the arrival of the Renaissance, renewed interest in the conquest of the seabed spread among the scientific community. An example is Leonardo da Vinci (1452-1519), who designed boat-shaped shoes for walking through water and a type of gloves and webbed fins inspired by the legs of frogs that, Together with a leather hood with a tube in the mouth to breathe, they formed the first light diving equipment in history. As a result of the fear that existed at the time of "sea beasts" it incorporated into its numerous hood spikes, with the purpose of protecting the diver from attacks by marine animals.
Years later, Leonardo himself would affirm: "There is too much malevolence in the hearts of men to entrust them with the secret of underwater exploration, they would not hesitate to take murder to the abysses of the sea."
Submarine bells in the 17th and 17th centuries
The evolution fundamental in submarine bells happened between the 17th and 18th centuries. The advances consisted of the incorporation of stabilizing ballasts, the introduction of benches and stools to sit on their >interior and the creation of small windows or glass sights, through which the bottom and location of the important remains of the shipwrecks could be observed to easily recover them.
But the most important discovery, and one that they had been searching for for centuries, was the way to introduce air inside, renew it and be able to stay underwater longer.
The famous astronomer Edmon Halley managed in 1690 (based on the ideas of the French physicist Denis Papin), to introduce air from the outside into a bell. Firstly, he introduced modifications to its design, increasing its dimensions (2.50 m in height and 2 m in diameter at its base), covering it with lead so that it could withstand the increase in pressure and improve its balance. He introduced a circular bench around its perimeter so he could sit and rest inside.
How was the air renewed?
The way it renewed the air was by lowering barrels full of air next to it, which was emptied inside with tubes. The tube connected to the barrel opened at the other end into the bell. Afterwards, a hole was made in the barrel and when it was flooded with water, the air passed inside.
In addition, it gave the divers a certain autonomy, providing them with a small bell for personal use, connected with a tube to the main bell. In the test he dived with four other men, staying for about an hour at a depth of 16 meters.
A few years later, the British carpenter John Lethbridge built a wooden cylinder, held by two rings to chains. The diver was placed horizontally and had two holes that allowed him to extend his arms through the bottom. Breathing the volume of air that fit inside it, it remained for more than twenty minutes at a depth of 16 meters.
In 1734 in the French port of Marseille, it was used to recover the cargo of coins from a sunken ship 10 meters deep. In 1735, he recovered with his team on the coast of Portugal, 350 ingots and thousands of pieces among the remains of the Slot Her Hooge, a Dutch shipwreck that made the route to the Indies.
Finally, all the scientists of the time were clear that the objective was to continuously introduce air into the bell, to increase the autonomy of the divers. The first to achieve this was an English engineer called John Smeaton (1724-1792), who connected some tubes to the bell linked to a pneumatic pump through which men pumped air at continuous pressure to his interior, from the surface.
The use of underwater bells in Spain
The first use of a bell in Spain (1538) was not carried out at sea, but in the Tajo River as it passed through Toledo. The Englishman John Teniers recounted how two Greek divers performed a demonstration inside a bell, remaining underwater for twenty minutes with lit candles, before Emperor Charles V and his entire court.
Probably, this experience served to increase interest in applying this discovery in the recovery of cargoes from sunken Spanish ships. In 1626, the Spanish Núñez Melián, with the help of a bell, recovered a large part of the gold and silver cargoes from galleons sunk in the Caribbean.
Later, in 1654 and in the coastal waters of Cadaqués (Spain), Andreu Ximénez used a bell model designed by him to explore the depths of this Mediterranean enclave.
This is how in Spain, starting in 1787, divers schools were created in Cartagena (Murcia), Cádiz and El Ferrol (La Coruña) who learned to scuba in apnea with the use of bells to breathe underwater.
