I wonder if Carmichael is suing him too?

The following is copyright, O. Michael Gray, 2004, and is not to be
reproduced in any form.

E.R. Cross, an ex-Navy Master Diver and owner of California’s Divers
Supply Company, bought the first home made single hose rig he ever saw
on the spot, a California beach in early 1947, and immediately began to
make improvements. By 1949, he had developed the Sport Diver, the first
commercially produced modern single hose scuba gear. The Sport Diver,
pictured on the title page, had a single tank (38 cubic foot at 1800
psi) worn valve up with a streamlined fairing over the tank top and
first stage. Intermediate pressure was very low by modern standards, as
low as four or five psi. The Sport Diver was offered by Divers Supply
for $79.95 complete with tank and harness. Cross did little to promote
his single hose rig, believing then that recreational diving would never
be a big deal, and probably only a thousand units were sold. Sometime
around 1953, Cross stopped making them and the unsold stock was
reportedly sold in a surplus store for $5 each.

At the same time, in Australia, Ted Eldred gave up salvage diving and
began designing equipment used to administer anesthesia. In 1948 he
studied the aqualung from Australian government documents, and decided
he could do better. In 1949 he completed and tested a prototype. He
produced a few for sale and in 1952 formed the Breathing Appliance
Company to make and distribute his single hose system, the Porpoise.

The Royal Australian Navy was very interested in CABA (Compressed Air
Breathing Apparatus, as it was known down under) and issued requests for
a rugged, dependable SCUBA unit that could also be used as a hookah
unit. The RAN specified that such a unit should be capable of supporting
a hard-working diver in cold water.

The 1954 Porpoise Universal was a very high performance regulator using
single or twin tanks (40 cubic feet at 1800 psi) worn valve down. Eldred
used a small diameter high pressure hose (to accommodate the higher
intermediate pressure, 100 psi) from the balanced piston first stage to
the vacuum assisted second stage. The kit came complete, in a trunk,
including a pressure gauge and an instruction manual with a reminder to
check the tank pressure before diving.

The RAN had the Department of Defence Standards Laboratory evaluate the
aqualung and the Porpoise in 1954. The Porpoise won. When the RAN
adopted the Porpoise as standard equipment later that year, it became
the world’s first navy to adopt modern compressed air SCUBA.

Eldred, with RAN advice, ran a training school, the School of Underwater
Diving and Swimming, for buyers of the Porpoise. The Porpoise dominated
the booming Australian professional and recreational SCUBA markets in
spite of competition from US, German, French, Spanish, and British
companies.  By 1960, the Porpoise was outselling the aqualung in
Australia, but Eldred’s company was undercapitalized and unable to grow.
The company was sold to La Spirotechnique, the subsidiary of Air Liquide
that owns US Divers and Aqua Lung, and the name was changed to
Australian Diver Spiro. Although the Porpoise was almost certainly the
finest SCUBA rig in the world at the time, Air Liquide ceased production.

Neither Cross’ Sport Diver nor Eldred’s Porpoise were ever patented, and
historians argue whether Cross or Eldred is the father of the modern
regulator. It’s hardly worth arguing, as both arrived at the same point
at the same time, at opposite points on the globe. Eldred’s Porpoise had
a purity of design and elegance of engineering that Cross’ Sport Diver
lacked; E.R. Cross wrote that “my real effort was to create a safe
diving system that did not have to pay royalties for an inferior,
potentially hazardous dive system.”  Eldred’s commercial success speaks
for itself, and it is claimed that the Porpoise was the equal of today’s
regulators in design and performance.