Diving equipment has been a subject of constant development since it was invented centuries ago. About 50 years ago this evolution made a new general type of system emerge, called lightweight diving apparatus. This term refers to a wide variety of gear that uses helmets and masks with air supply from the surface. The diver may choose what kind of suit to use: in hot water he wears only his swimming trunks, in very cold he wears a dry suit. Today a main difference between lightweight and heavyweight gear is that lightweight helmets and masks are not integrated with the diving dress (early lightweight gear like the Dräger DM 220 and the Advanced 2000 had a corselet and were integrated with the suit). The suit has no air in it. There is no risk of a blow-up. The amount of weight needed to stay down is low. In short: lightweight equipment has many advantages.

The modern lightweight diving equipment can be categorized in:

Air helmets

Joe Savoie deserves the credit for developing the first lightweight practical air helmet with a neck dam seal in the 60-ies. Air helmets have a bonnet that encloses the diver's head. They look like the heavy weight helmets but their size is smaller. They can be made from different materials like fiberglass, plastic, steel, aluminum of copper. On many of the modern hats you only see one light: the front glass. It is big and gives a perfect view.

Air is supplied through a hosepipe from the surface, it can be regulated by a valve built into the bonnet.  The bonnet also features an exhaust valve. Sometimes it can be operated from the inside by a head- or chin button. These days many modern hats have a exhaust valve that is operated on the outside by hand.

Many helmets are fitted to a neckring by either an interrupted screw thread or a clamping device. An O-ring provides a watertight seal between the two. The neckring has no corselet like on the old hats but a piece of rubber, called a "neck dam seal". This neckring runs from wide to narrow: when the diver pulls it over his head, a tight fit is achieved around the divers neck.

Lightweight helmets tend to float when they are under water, because they are made from light materials. Therefore the neckring is kept in place by a kind of armour or just a simple jockstrap between the divers legs.

Diving this helmet is easy: the diver only has to control the inlet and the exhaust valve. There is no danger of a blow-up: if there is too much air in the helmet it will bubble out at the neck dam seal. If there is an air-failure, the non-return valve will close. Water will of course rise up to the neckring but cannot enter the helmet due to the air pressure inside it. Most air helmets feature a communication system. Visit the virtual helmet and mask collection to learn more about helmets. Most major manufacturers now make lightweight helmets in both an air and a mixed gas version. Mixed gas helmets have an additional backpack containing CO2 absorbent and circulation pump. 

Band masks

This mask was not only accepted by the US Navy but also widely accepted by commercial divers all over the world. The bandmask has a fiberglass frame that holds a plastic front glass. On the inside of this front glass is a rubber gasket that forms a water tight seal against the divers face, enclosing his eyes, nose and mouth. Another smaller (extra) gasket is fitted inside to just hold the divers nose and mouth. There is an inlet valve on the side that holds a non-return valve. Air enters the mask from there. Some masks are built as "free flow masks" having a constant flow of air, some are built as a "demand mask" where inhaling causes a flow. In this last case the air comes through a regulator that equals the air-pressure to that of the surrounding water. Some masks are built with both options and the diver can choose which one he wants to use. On most masks there is a third posibility to get air: if anything goed wrong with the surface air-supply the diver can switch to a tank holding compressed air he carries on his back (the bail-out service). These tanks only provide air to come up directly in a safe way and not to continue the dive ! The mask is held to the divers face by a rubber hood. The mask also features a communication system. 

Face Masks

Jack Browne is the guy that invented the face mask. It is perfect for use in shallow and uncontaminated water. This mask consists of a triangular frame that holds a glass faceplate and is attached to a rubber frame. This rubber fits around the divers face and encloses eyes, nose and mouth. On the right side of the mask, an air-inlet with non return valve is mounted. The exhaust valve has a rubber disk that is kept closed by the water pressure and opened by the diver when he exhales. 5 rubber straps keep the mask on the head. This mask is easy to put on, offers good vision and has an unlimited air supply. The major disadvantage was that this mask had no communication system. This can now be purchased separately for many masks. In the picture you see a free flow mask with communication system. Photo courtesy of DESCO.

All this doen not mean that diving with heavy-weight equipment is over ! The equipment is used every day all over the world because it still has several advantages over the modern lightweight equipment. It is used in contaminated water, water with no visibility or in strong currents. It is also still used in dock works or in the salvage of ships. The diver is safe inside his suit and stands firmly on the bottom. However, many people feel that it is only a matter of time for the new developments to definitely push the old heavy gear aside.

We truly hope that www.divingheritage.com will contribute to a worldwide knowledge and understanding of standard diving today and how it all started centuries ago.