I apologize to the hundreds of diving pioneers that weren't
included in this very brief overview. I hope that the hyperlinks and
posts that follow will lead you to their fascinating stories.
Timeline of diving technology
How did we get here?
"You can't fully comprehend diving
history without understanding
engineering history"
The story of advancing beyond ancient breath-held diving is more about "enabling technologies" than building on the shoulders of earlier undersea pioneers. Nothing is more fundamental to modern diving than the ability to move, compress, and convey air.
Although the social need for collecting sea food and lost object recovery (salvage) predates human civilization, it was not as critical or widespread a need as moving water. Mechanical positive-displacement pumps powered by humans and animals were eventually applied to firefighting. People also discovered that these devices could pump air.
Firefighters needed a flexible method of conveying water from the pump to the fire so
hose was invented. Most accounts describe the first hoses as being made by sewing leather around wooden mandrels. Advances in fabric and vulcanized rubber manufacturing led directly to modern hoses made today.
The First Successful Diving System
John Deane patented the "Smoke Helmet" in 1823. The copper and leather helmet was supplied through leather hoses fed by a manual air pump and allowed firefighters to enter smoke filled spaces. The smoke helmet was eventually manufactured by
Augustus Siebe in 1827. John and his brother
Charles Deane modified the design so it could be used underwater. The leather was extended lower on the torso but remained open at the bottom, requiring the diver to stay more or less upright to prevent air escaping and flooding the hat.
Augustus Siebe improved the design in 1837 by replacing the open-bottom extension with a full canvas suit that attached to the helmet. That allowed divers to work horizontally. Siebe and his son-in-law, Gorman, formed
Siebe Gorman which became the leading manufacturer of diving helmets for nearly a century. The company developed a close relationship with the
Royal Navy. A classic text on the company, products, diving history, and lore can be found in
Sir Robert Davis' book,
Deep Diving and Submarine Operations. My copy of the 7th edition, volume 1 and 2, has over 700 pages.
Augustus Siebe's original closed diving dress is known by
quite a few different names:
I will call it "heavy gear".
Personal Sidebar
I was trained to use Mark V heavy gear at the US Navy Second and First Class Diving Schools in the early 1970s. I had been a recreational Scuba diver since 1962 with an obsessive fascination with advanced deep diving.
So, here I am sitting on a wooden bench aboard a barge at 32nd street naval station in San Diego Bay. Classmates are bolting me into this really primitive rig that was invented about a generation before the US Civil War. To be fair, this was the "updated" version of Augustus Seibe's invention... as-in Chief Stillson's 1915 update!
My classmate-tenders screwed the hat to my breastplate with a 1/8th turn of the interrupted screw threads, secured the dumbbell (locking mechanism), and give me two pats on the hat... meaning stand up and walk to the ladder. This was the moment when the origin of the name "heavy gear" became crystal clear to me. It outweighed me by over 30 Lbs (13 Kg).
View attachment 425552
The two most recognized heavy gear hats are the Siebe Gorman Admiralty Pattern 6 bolt (left) and the US Navy Mark V.
The common characteristics of heavy gear include a helmet (hat) and breastplate that attaches to a suit that fully encloses the diver, or includes wrist seals to expose the diver's hands. Air is supplied by a hose from the surface which is connected to an air compressor. Major improvements since Seibe's time include:
- Adding audio communications
- Simi-closed circuit recirculators to conserve mixed gas
- Enlarged view ports
- Adding a check (one-way) valve to the hat to prevent deadly suit squeeze
How do they work?
Most hats can be removed from the breast plate with an interrupted bayonet or a 3-bolt flange. Air
freeflows into the hat through an air control valve, either mounted to the hat or inline with the umbilical/air supply hose. Air flow rates to ventilate the hat are typically about 6 ambient CFM or 170 Liters/Minute. Air escapes into the water through an adjustable spring loaded exhaust valve which allows a slight back-pressure to be maintained in the suit.
Many hats allow the front viewport to open so the diver to breathe and talk while being suited up on deck. Air is directed past the front viewport to prevent fogging and minimize the effective dead-air space. Two-way communications is provided through a speaker mounted in the hat and connected to an amplifier on deck; often referred to as a radio, phone, or comm box. Divers that require the
Valsalva Maneuver to equalize their ears press their upper lip against the inside of the hat to block their nostrils.
Suits were originally constructed from heavy canvas with vulcanized rubber lining. This material was replaced by fiber-reinforced vulcanized sheet that is similar to modern
Haz-Met drysuits, but a couple of times thicker. A heavy rubber "gasket" that matches the bolt-pattern on the breastplate provides access to don and doff the suit. Most suits include heavy vulcanized rubber wrist seals but some have integrated 3-finger gloves.
View attachment 425553
This image is of of me in a Mark V Helium Hat during US Navy First Class Diving School in 1971.
The tender is soaping-down the suit during a pressure test looking for leaks as part of the pre-dive check.
A considerable amount of weight is required to counteract the buoyancy of the suit and hat. The US Navy Mark V components weight:
- Air Hat and Breastplate: 54 Lbs (25 Kg), Helium Hat: 92 Lbs (42 Kg)
- Weight Belt: 85 Lbs (38 Kg)
- Boots (pair): 35 Lbs (16 Kg), 2x weight with Helium Hat
Some hats are designed for lead "breast weights" that hang off pegs on the breastplate. Surprisingly, suit inflation can be controlled so that you are nearly neutral. It can also be adjusted so that you are about 50 Lbs (23 Kg) heavy or 200 Lbs (90 Kg) positive. This attribute is very useful when working on the bottom with a waterjet, jack hammer, or lifting heavy objects... just don't let go of that weight before deflating the suit!
Continued in the next post
