Part 1: The Oldest Diving Suit in the World
Diving is about pressure. The pressure that the weight of water exerts on the body. And the pressure needed to compress air, either forced down a hose from the surface, or carried in a tank, to act against the weight of that water.
During the 18th century, diving bells were built, modified, and began to be used around the world. Mostly the diving bells were made from wooden barrels, open at the bottom, and were large enough for one or two people to squeeze inside. They needed heavy weights to overcome the positive buoyancy of the trapped air and, consequently, they needed to be lowered underwater from a derrick or crane. That meant diving bells required a large ship and a team of workers to get them in and out of the water. It also meant they were expensive to operate, so salvors needed a large capital investment. Salvage companies, backed by investors, began to purchase ships and diving bells, hire crews, and search for shipwrecks with expensive cargoes.
But at the same time, individual salvors developed diving suits that were cheap to make and could be operated by a diver and one tender. Flexible diving suits were suitable for shallow water work, and did not need a large ship or expensive equipment. Salvors could enter the water by walking in from the shore, or going over the side of a small rowboat. Nor did they require heavy weights to overcome the volume of air trapped in a diving bell. Heavy boots and some additional chest weights were usually enough.
What diving suits did need however, was air pumped down from the surface via some sort of hose.
To understand the advantages and disadvantages of the diving suit as it was developed in the 18th century, we can turn to the one known example that still exists today.
The oldest extant diving suit in the world is on display in a museum in the small Finnish harbor town of Raahe, located on the Baltic Sea. Raahe has always been a seafaring town, and most of the objects in the small Museum of Raahe, which was established in 1862, were donated by ship owners.
Housed is a special glass display case in the museum is the leather diving suit, affectionally known as The Old Gentleman of Raahe.
No one knows who made the suit, or when. It was donated to the museum in the early 19th century. It is possible that some sea captain saw a similar suit being used somewhere, and brought the idea back to Finland. Wherever the idea came from, what is known is that the suit was made in Finland because the gloves and the boots are similar to what people used to make in the area. The suit is estimated to be about 300 years old and is made from cow leather.
What was the diving suit used for? Again, no one can be certain, but because of its location, many wooden ships came to Raahe to be repaired. It was not uncommon for wooden sailing ships to leak, and often those leaks could only be repaired when the ship was out of the water. Hauling a sailing ship out of the water to repair small leaks was expensive and time consuming, so it is possible the diving suit was an easier way for a person to inspect a hull, or effect minor repairs while a ship was anchored.
Were anyone to try to dive The Old Gentleman of Raahe today, they would need to be no taller than five feet three inches (1.6 m), suggesting it may have been made for a specific male, or possibly female, diver. The one-piece suit, which includes a hood stretched over a wooden frame, is made of cow leather. The seams are sewn with waxed thread and sealed with pitch. The leather itself is made partly waterproof by a mixture of pig lard, tar and pitch. The diver entered through an opening at the front of the body of the suit, before the flaps covering the opening were rolled together and clamped to make them watertight. In front of the diver’s mouth is a hole, about four inches in diameter, into which air was pumped. The air hose appears to have been a series of wooden tubes, wrapped in leather. At the lower back area is a one-way valve that lets air escape. The diver looked through two glass portlights in front of his or her eyes.
A few years ago, the curator of the Museum, Jouko Turunen, made a copy of the suit. It was immediately dubbed The Young Gentleman of Raahe. The idea was to copy the 300 year old suit as closely as possible and manufacture it with the same traditional methods, which included saturating the leather. Turunen explained that he made the replica suit a little larger than the original.
A day of diving was organised by the Historical Diving Society of Finland, along with members of the local Walrus Diving Club. Various divers tried The Young Gentleman of Raahe. The divers climbed into the suit through the opening in the belly, and then the flaps were folded over and made watertight. In the original suit air would have been supplied by a hand operated bellows, but for safety, when the modern divers used it, air was supplied from scuba tanks.
In the water The Young Gentleman of Raahe squeezed against the diver’s legs, but the upper part of the suit was kept from collapsing by a wooden framework.
Divers who had a turn in The Young Gentleman of Raahe reported that diving 300 years ago must have been very laborious.
But the biggest issue facing divers who crawled into leather diving suits in the 18th century was the supply of air from the surface. In the early 1700s, the only known method of pumping air down a leather tube to a diver, was a hand operated bellows.
Since the replica of The Old Gentleman of Raahe was dived, members of the German chapter of the Historical Diving Society have built a replica of another 18th century diving suit. This is a replica of a suit designed by Peter Kreeft. Although the Kreeft suit does not exist, detailed drawings of it do.
The German replica adhered as closely as possible to the drawings. An organ builder made the bellows, a leather tailor made the suit, and the metal parts were fashioned using contemporary techniques. The modern replica consists of a leather helmet hood and jacket, and leather trousers. Once the diver is inside, the upper and lower sections are bound around the waist with rope. The ends of the sleeves are also bound tightly with rope. The diver wears metal-soled sandals, as illustrated by Kreeft. Two hoses run from the surface to the hood. One hose is a speaking tube, while the other supplies air.
The Kreeft replica suit was tested by professional divers in a swimming pool, with safety divers standing by in the event of flooding. The problems confronting 18th century salvors in flexible suits immediately became apparent.
Franz Rothbrust, of the Historical Diving Society: Germany, explains: “It is not possible to make a leather suit 100 percent waterproof. The helmet seams leaked as well, but that is not a problem. Water does not come inside when the air presses outwards. They must have had the same problems in the old times, because pitch and tar do not seal seams tight against air pressure. But not much water came in. Maybe half a litre each hour.”
Leaking seams and hoses could be overcome and the diver kept reasonably dry, as long as the source of compressed air from the surface was at a higher pressure than the surrounding water. The air, not the waterproofing, kept the water out.
The all-important bellows, when made to the size shown in one of Kreeft’s illustrations, proved impossible to use. It was too large. A strong person had extreme difficulty squeezing the handles together once the diver reached even a few feet underwater. When the bellows was made smaller, it did not supply enough air. Franz Rothbrust, designed a twin bellows arrangement that mounted to a platform and had a handle. A standing person could pump air from both bellows in a push and pull motion. Rothbrust explains, “The twin bellows can deliver up to forty litres per minute at 0.5 bar (7.25 psi). So, we can dive to about five meters depth (16 ft) at the diver’s head.”
In the 18th century diving suits were limited to shallow depths because of a lack of a compressed air from the surface. But that was about to change, because the Industrial Revolution would soon replace hand operated bellows with piston-driven pumps.
