SPONGE DIVERS were the first men to venture below the waves to explore the sea bed. When diving for sponges they would tie a rope around their middle, a curved knife rather like a bill-hook in one hand and a heavy stone in the other. The stone took them very quickly to the bottom. Without any protection from the effects of the increase in pressure on their lungs and ears below water, many of these divers suffered burst ear drums and many lost their lives.

DIVING HELMET Leonardi da Vinci 1452-1519 Made out of a rigid leather, this helmet was provided with a narrow breathing tube which was fitted with a cork float to hold it above water. The helmet is covered with spikes to protect the diver from attack by underwater monsters! The eye-holes are fitted with glass lenses. Leonardo da Vinci was very interested in a wide range of scientific activities and in one of his sketches he shows a swimmer wearing webbed gloves and flippers.

UNDERWATER SALVAGE Diego Ufano 1628 A diver wearing a hood of greased cow hide made to cover the diver from head to middle. The sleeves came to the elbows to be tightened with cords to prevent water entering. All seams were carefully stitched to make them water-proof. From the top of the helmet a long tube of greased cow hide was held above water by pig or ox bladders to allow the diver to breathe. (Fact: the diver could only breathe provided he never went more than a few feet below the surface. The increasing pressure at depth would prevent the diver from breathing and he would suffocate. This scientific error was made by many inventors who were unaware of the laws of pressure).

BORELLI (1608-1679) Here we see a prototype of the 20th century frogman. The diver is covered in a suit made out of goatskins carefully fitted to his body. His head is inside a metal container fitted with a face piece to enable him to see underwater. His air supply is in a large bag which forms a closed-circuit breathing supply. Exhaled air could be refreshed by passing through a brass tube surrounded by water. A small sack leading off the brass tube was supposed to take out any impurities in the recycled air. From time to time the diver could return to the surface to renew the air. Borelli also provides his diver with flippers on hands and feet to enable him to swim like a frog. The volume of air in the long cylinder could be varied to make the diver lighter or heavier by adjusting the piston.

KLINGERT’S DIVING OUTFIT 1797 Invented by a German, this is one of the earliest pieces of diving apparatus. Tried out in the River Oder, the suit was provided with a reservoir of air (a metal box with a pump-like cylinder at one end). There was a piston inside the cylinder and as the diver descended in the water the piston was forced to compress the air to the same pressure as the surrounding water.

BRIZE-FRADIN APPARATUS 1808 This apparatus could be described as one of the forerunners of the aqualung. The diver was enclosed in the suit. He carried a supply of air in a container attached to the back of his suit.

LE TRITON Frederic de Dieberg 1809 The diver receives air from above. By moving his head he operates a system of rods which work a bellows carried on his back. The air from the bellows is compressed which helps the diver to breathe more easily. Note the candle in the jar to provide light underwater.

DIVING SUIT - 1882 A heavy piece of apparatus built built by the Carmagnolle brothers of Marseilles. It was never used. It is now in the Naval Museum. This unwieldy suit of thick armour had a helmet with 20 glass eye-holes in it. The suit has been described as “the hollow statue”.

ROUQUAYROL-DENAYROUZE APPARATUS 1860-1865 Air from the surface was supplied to the metal canister on the diver’s back by means of an air pipe attached to a pump. The air pressure inside the canister was maintained at a pressure between 25 and 40 atmospheres. The breathing apparatus itself is important since it marked the first use of a “regulator” to automatically equalize the pressure between the water surrounding the diver and air he breathed. The principle of this regulator was adapted by Cousteau and Gagnan in 1943 to bring underwater exploration within the reach of everyone.

SIEBE’S CLOSED SUIT - 1837 The industrial revolution brought new materials and metals which enabled Siebe to construct an efficient diving suit using copper, steel and rubber. The rubber was used for making excellent waterproof fabric. Siebe’s suit has a metal helmet and shoulder piece. The suit enclosed the diver like a loose-fitting skin. The hands protruded from the suit but tight-fitting cuffs formed a seal. Air was pumped into the metal helmet through a one-way valve. Using this type of suit a diver can work at depths of up to 250 feet breathing air compressed to the same pressure as the water surrounding him. At this depth the pressure is approx 188 psi.

SNORKEL BREATHING 1938 The snorkel was developed by the Germans towards the end of WWII which enabled submarines to use their diesel engines when submerged in shallow waters. Now standard equipment on diesel-powered submarines. The snorkel shown here is a simple device which allows a swimmer to breathe with head below the surface of the water. The eyes are protected with a pair of goggles and the swimmer is given an uninterrupted view of the world below the waves.

AQUALUNG DIVER Cousteau-Gagnan 1943 Tried for the first time in 1943, Cousteau swam to a depth of 60 feet and experiences no discomfort from underwater pressure. The special feature of the breathing apparatus is its “demand” valve which makes sure that the supply of air to the diver is at the same pressure as that of the surrounding water. The diver is free to swim almost as a fish and is limited only by the amount of air in the tanks and the depth to which she can descend. Beyond a certain depth a special mixture of helium and oxygen is necessary. Free diving to depths of over 500 feet have been recorded but 300 feet is the real limit for fit well-trained divers.

ARTICULATED METAL DIVING DRESS (Modern) This suit is used for working at depths up to 600 feet where pressure is about 270 psi. The diver is inside a strong hermetically sealed suit of metal which protects him from the tremendous water pressure. The air inside the suit is maintained at normal atmospheric pressure since its only purpose is to provide the oxygen the diver requires for breathing. This type of suit is clumsy and difficult to work in. There are difficulties in operating the articulated limbs of the suit and the diver’s vision is very restricted.

DECOMPRESSION CHAMBER (Modern) Breathing air at high pressures saturates the body fluids with gases. If a diver comes to the surface quickly these gases bubble out of his body fluids like bubbles in a bottle Pepsi when it is opened. This can cause a very painful condition called decompression sickness and death can result. To avoid this illness divers must be raised to the surface slowly ( a diver working 1 hour at 200 feet must take 3 hours and 50 minutes to return to the surface). A Decompression Chamber is lowered to the depths where a diver is working and air is pumped into the chamber to equal the pressure of the water outside. When the diver enters the chamber the hatch is closed and the chamber is raised to the surface. Inside, the diver can relax in comfort while the air pressure is lowered in stages (decompression). This takes place on board the ship.

POSEIDON, OR NEPTUNE, GOD OF THE SEA According to legend, Poseidon lived in a fabulous mother-of-pearl palace deep under the Aegean Sea. When leaving his underwater kingdom he wore a gold breastplate and rode in a fiery chariot drawn by magnificent horses with flowing manes. In one hand he carried a trident which was the symbol of his authority over the seas. It was said that dolphins, sea dragons, hippocamps and centaurs would rise to the surface and follow his chariot to keep him company.

The earliest recorded useful information about a submarine. BOURNE’S PROPOSED SUBMARINE - 1578 Holes in the side of the hull allowed water to flow into flexible ballast tanks. A close-fitting wooden plate lined with leather could be moved from inside the submarine by a screw device making the tank larger or smaller. In this way the vessel could be adjusted to float or sink. A hollow mast fitted to the deck extended above water to supply air when the vessel was submerged. The earliest recorded useful information about a submarine.

Cornelius Van Drebbel - 1620 UNDERWATER GALLEY Cornelius Van Drebbel - 1620 Van Drebbel, a Dutchman, is regarded as the first submariner and his underwater galley as the first submarine. His invention was a leather covered galley with oars for twelve rowers. This strange machine could go underwater - it actually worked. It was used on several occasions to take people for underwater joy-rides in the River Thames. It is said that James I himself became interested in the craft and took an underwater ride.

STURMIUS DIVING BELL - 1678 As the bell is lowered into the water the air inside the bell is trapped and compressed. Water rises inside the bell until air-pressure and water pressure are equal. From the waist upward the diver’s body is in air while his lower trunk and legs are in the water. The bell allowed the diver to use his hands and feet and once on the bottom he could walk around on the sand or stones.

HALLEY’S DIVING BELL - 1690 Halley built a diving bell constructed out of wood, 3 feet in diameter at the top and 5 feet diameter at the bottom. To make it sink it was weighted with lead. This bell could hold several divers at the same time. Air inside the bell was renewed by means of large barrels. The barrels were filled with air and weighted to make them sink. A flexible tube from the barrel allowed air to transfer from the barrel to the bell. Halley used a pair of barrels raised and lowered alternately to keep his divers supplied with fresh air.

LETHBRIDGE’S DIVING SUIT - 1715 The diving suit was a watertight case of leather consisting of a barrel six feet long tapering from 2 ½ feet diameter at the top to 1 ½ feet diameter at the base. The diver could put his hands through two holes in the side and when submerged his arms were used to “walk” over the sea floor. Lethbridge made many dives in this suit - dives to 60 feet lasting for approx. six hours at which time the air inside the suit was almost used up. The suit was used in many parts of the world helping salvage cargo from wrecked ships.

BUSHNELL’S TURTLE - 1775 A strange egg-shaped craft built of wood with a small conning tower on the top. Submerged when ballast tanks were filled with water. Horizontal and vertical propellers, worked by cranks provided backwards and forward and up or down movements. Made an unsuccessful attack on a British man-of-war in New York harbor – the first recorded attack by a submarine.

FULTON’S NAUTILUS 1798-1801 Built by American engineer Robert Fulton, this craft was 21 feet long and had a copper hull shaped like a huge cigar. A crew of three propelled the Nautilus by turning a crank connected to a propeller. The Nautilus was also fitted with a sail for use when on the surface.

ARGONAUT II - 1900 Built by the American submarine pioneer Simon Lake. Designed as an underwater headquarters for divers. It had an air-lock door through which divers could enter. It was fitted with wheels to enable it to move along the sea floor. It was propelled by an internal combustion engine and had electric lights. Had a crew of five. Argonaut I was 36 feet long and made a successful voyage of 2,000 miles.

U-BOAT 1914-1918 The U-BOAT (Unterseeboot) which made its appearance during WWI was made by the Germans. This submarine quickly proved the effectiveness and menace of undersea warfare. Merchant ships, battleships, etc. all suffered losses as a result of U-BOAT activity. One U-BOAT sank three British cruisers in one engagement. Since WWI, the submarine has been developed for undersea warfare and during WWII it has been estimated that approximately three quarters of all damage to ships at sea happened as a result of submarines.

BATHYSPHERE Bebe and Barton 1930 A steel sphere built to withstand a pressure of over 100 atmospheres. The sphere was 4’9” in diameter with walls 1 ½ “ thick. The entrance was like a manhole secured with ten bolts. Two cylinders of oxygen provided sufficient air for eight hours. The sphere was lowered into the sea at the end of a steel-cored cable about 1” thick.. June 6, 1930 - 800 feet June 11, 1930 -1,426 feet August 15, 1934 – 2,510 feet

NAUTILUS 1954 The world’s first atomic-powered submarine launched on Jaunary 21st, 1954 at Groton, CT. Has a range of 30,000 miles without surfacing. Reached the North Pole at 11.15 pm, 8/3/58 and became the first underwater craft to sail under the ice cap to the pole. (1.830 miles without surfacing)