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Has anyone heard of guards or patrollers or the like using any of these?:-
(1) Small submersible craft (either a mini sub, or a lighter-than-water
craft that can get up speed and then duckdive for a short time) equipped with
a grab or suction or scoop or net device to catch attacking frogmen or any
other unauthorized or unidentified submerged divers.
(2) Aimable powerful underwater ultrasound gun (I saw these mentioned in a
book written by a man called Diole' who dived with Cousteau.), handheld (by
diver or overside) or hull-mounted. Underwater ultrasound can be dangerous. It
is lucky that the 1939-1945 war did not cause underwater ultrasound technology
advance to the extent of such ultrasound guns getting into general use by
small-boat inshore fishermen as weapons against seals and sharks that damage
nets, and thus all too handy to stop in its tracks the 1960's mass sport diver
invasion of shellfishing areas in the time when inshore fishermen kept
complaining about scuba divers taking shellfish.
(3) Underwater loudspeaker to warn submerged unidentified or unauthorized
divers to "surface and identify yourselves or we fire / take action".
(4) Toughened diving gear for patrol craft's crew (ref (5) below): Kevlar-
reinforced rubber in diving suits and in rubber parts of breathing sets. Light
small rebreathers for maximum agility and speed: bag and tubes toughened;
tubes kept close in to the body and not in long trailing loops, reinforced
with interlocking hard rings to prevent cutting and squeezing; with the
minimum of projecting parts to snag on nets or cause hydrodynamic drag; safety
helmet and hard smooth rounded fullface mask.
(5) I read in the real world of French sea-police divers trained to find
divers who are doing anything illegal (in unauthorized place, spearfishing
with aqualung, etc) and to force them to surface by turning their air off.
This was in the 1960's or 1970's.
(6) I have seen electrical anti-frogman devices mentioned in newspapers as
perhaps mounted on hulls of warships.
These may be to protect naval etc bases, or anything underwater liable to
theft or poaching, or simply for controlling for the sake of controlling, in
these days of common public availability of frogman kit.
(5) above, and such things as a series of letters in a UK diving magazine
about someone's air being turned off from behind at depth (he suspected
hooliganism, but other opinions suspected that the same can happen by pushing
through thick kelp (Laminaria, not Macrocystis, here)), lead me to this:-
Why can't aqualungs be designed with their air valves so the diver can turn
them (off or) on while wearing the aqualung? I used to have a cylinder made by
Submarine Products in Hexham (England) (now closed down), which was strapped
straight to the back without backpack and was long and thin, so I could reach
and operate its on/off valve while wearing it; this was useful to me. I have
seen diving and industrial aqualungs (and prewar constant-flow compressed-air
sets) with the valve at the bottom of the cylinder, much easier to reach, with
a hard intermediate-pressure tube going up to the top of the cylinder. I have
heard recently of modern single-hose regulators with their intermediate-
pressure hoses so long that they can reach the diver's mouth easily when the
cylinder is put in the stab jacket with its on/off valve at the bottom; but
that would mean a great length of hose to trail in the water causing drag and
to snag on things.
How much is put into designing diving gear (aqualungs and rebreathers) to be
better streamlined? The usual modern aqualung and its trailing parts have much
hydrodynamic drag both in swimming forwards and in turning over. The cylinder
standing away from the body increases the rotation inertia as well as the drag
when he has to turn over. Compare how easy it is to roll over when snorkelling
compared to with an aqualung. But British wartime frogmen's rebreathers were
beautifully streamlined. In designing production-model mixture rebreathers,
<<please>> watch the diver's streamlining and rotation-inertia [= what
some
call "radius of gyration"]!, to make it easier for the diver to swim and to
twist and turn. In a modern aqualung with two regulator hoses and a pressure
gauge trailing, and the flat back end of the cylinder making tail eddies, I
find that the expression "wearing drag" is no figure of speech but literal!
Even more so in a Cis-Lunar long-duration mixture rebreather that I saw a
photo of: it had two separate old-aqualung-type breathing tube loops round his
neck, and TWELVE! thin hoses of various purposes coming over his shoulders.
With the set in a box on the back, I once thought of this sort of breathing
tube: the loop of tubes is built into the harness, coming over his shoulders
and across his chest, lying against his body. From that a short free breathing
tube, or pair of tubes, goes to a hard smooth rounded fullface mask with eye
windows. Any valve to switch between breathing from set and breathing from
atmosphere, is under the fullface mask behind where the breathing tube comes
in; I have heard of; the old-style Siebe Gorman fullface mask's forward-placed
set/air valve was liable to be switched accidentally to `breathe from the sea'
by kelp stems etc when pushing through kelp or the like underwater.
When in the 1950's scuba diving started to become a sport, in Britain the
Navy and Siebe Gorman seem to have tried to keep it to themselves and diving
gear too expensive for most people, and to have said that cold dark British
water is "not the place to muck about in frogman's kit for fun". So sport
divers makeshifted, and to them in Britain the Russians quietly turned to find
about diving gear when official bodies would have been unlikely to tell in
those days of the Cold War. At a regulator repairer's in Liverpool I saw an
early Russian aqualung once: easy to see what UK sport divers' backstreet
workshop throw-together it was a somewhat improved copy of: high pressure
valve off a blowtorch, propane-type intermediate connection, low pressure
valve made from a `Calor' bottled butane regulator, tank meant for RAF pilot's
oxygen, other parts home-made. Also the Russian for "aqualung" is `akvalang',
and not `skuba' or some word made up in Russian.
I have a photocopy of an article "How to make an aqualung" in a handyman's
magazine from that period. The aqualung that it describes is a curious
foreshadowing of the single-hose set; from the top of the cylinder an
intermediate pressure hose ran to a (converted Calor gas) second-stage on his
chest, and that was connected to his mouth by a loop of hoses like an ordinary
old-style aqualung. The mouthpiece was taken from a snorkel.
From another source I even heard of early home-made sets using a gasmask
(minus canister) as a fullface mask.
I saw mention once, in the dark days before regulators were commonly
available in UK, of a compressed-air set with a breathing bag, not a
rebreathing bag but to catch the flowing air until the diver breathed in next.
It is ironic that way back in (I think) the 1860's Rouquayrol and Denayrouze
designed an aqualung-type regulator. But there were no cylinders then, only
spherical tanks that could hold only 30 ats, only of use as a bale-out, and
the diver was surface supplied (and wore weighted boots). By the time good
cylinders were being made, the regulator was forgotten. Various constant-flow
air sets came to nothing, and the wellknown Siebe Gorman hardhat kit overtook
Rouquayrol's set before good cylinders came along. Jules Verne equipped
Captain Nemo's fictional divers with Rouquayrol sets without external feed,
duration wildly exaggerated to 8 hours from a 50-at "cylinder", but made no
mention of a regulator among his floundering attempts to describe how it
worked. If only Boutan (who made an early constant flow air set) had found
about the regulator! Then we could already have celebrated the centenary of
the aqualung.
This turns to asking the readers about any prize ignoramus-isms about diving
gear in fiction or the press etc, that have caught their attention.
There is the common newspaper habit of calling aqualungs "oxygen cylinders".
Comic strip artists can be treated as a sample of the non-diving public
forced to draw diving gear. In comics, wearisomely, the standard-issue diving
set including for combat frogman seems to be a two-cylinder twin-hose aqualung
with one breathing tube coming from each cylinder top with no regulator. E.g.
events set in a German wartime port, with two German standby frogman with
anachronistic Cousteau aqualungs on sitting on a wharf in case of anything.
(Not the only wartime anachronisms that I have seen! In "Ogpu Prison" (one
of Sven Hassel's many 1939-1945 German soldier novels) he mentions Russians
with Kalashnikovs, which were not invented till 1947! (whence the name AK47).)
Only twice have I seen a rebreather in a comic. Once was in the 1960's UK
comic `Eagle', set at the current time, underwater action, and one man on each
side wore a well-drawn rebreather, with the fullface mask air-pilot-shaped but
with eye windows like a gasmask or the fullface mask that came with the old
Siebe Gorman Salvus light oxygen rebreather. (I have seen that sort of
fullface mask on an aqualunger in a newspaper cartoon.) Once in a young
children's comic I saw a `frogman' with a breathing set composed of a flat
circular fullface mask with a big round window, connected by a wide tube to a
canister on the chest with no bag or tanks. Recently an Icelandic
trawl-maker's advertisement in a fishermen's (not sport angling) periodical
showed a man in scuba gear sitting on the seabed at a drawing board designing
a trawl; his aqualung was as described above with no regulator; each cylinder
had 4 bands round and two valves on top, and had likely been drawn using a
blowtorch or resuscitator as model. His bubbles came from somewhere above his
left shoulder that was hidden by his head. But his fullface mask was a good
copy of a real Spirotechnique fullface mask.
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\___/===\ \ A.Appleyard, E28d, UMIST, Manchester Univ\ \
\ \ UK. a.appleyard@fs*.mt*.um*.ac*.uk* \\
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