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Well, there is nothing like
experience. Scary stuff. Great to have it from the horse’s mouth so
to speak if you will pardon the _expression_. Any chance of getting a copy of your
presentation? I still haven’t finished my design let alone started
building. Been at it for 7 mths so far !! And yes I can imagine. I was just
cleaning out the swimming pool at 10 degrees C and I was thinking that was
enough of a problem with only my arm in it. Add burst ear drums and loss of where is
up and it’s a wonder there are any survivors. Grateful for the
explanation. Regards, Hugh From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Jay K. Jeffries Hugh, It was hard for me
to reconcile at first also. It is a density issue the air being buoyant
wants to rush out and it sucks you out with it and it entrains water with
it. I once cracked (fortunately didn’t open it fully) a hatch on a
sunken sub at 135 fsw. The ensuing gas escape caused a strong suctional
force upward and resulted in a boil 30 feet in diameter and a foot high at the
surface…pushed the surface support boat back to the limits of its
mooring. The Brits went back
to the Med and tested a later version of their escape apparatus/exposure suit
and broke their record by a short distance. The US Submarine Service has
now adopted the British-style escape apparatus (I believe the Mk-10) and
retired the Steinke Hood which I have previous used in practice as part of
submarine training. It is a rapid express train ride to the surface! In my presentation
was a table and graph that should for various depths how long you have to get
out of the sub and start for the surface. The deeper the water, the
shorter the time period. You can’t realize how debilitating the
temperature of the water can be. Reading accounts of previous escapes and
talking with one of the survivors from the USS
Squalus really sinks home that you want to make your escape efforts as
soon as possible if a better solution is not available. Something to keep in
mind that when we speak of hoods and escape apparatus from subs, this gear is
all made for large subs with dedicated escape chambers that facilitate using
this escape gear. We don’t have that option in most PSUBS. R/Jay From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Hugh Fulton Hi Jay, Obviously agree with you on flooding etc
and getting out but cant reconcile with being blown out if the sub was full of
compressed air. Just from a theoretical point of view:- As it would be at
same pressure as outside it would similar to opening the hatch at 2 ft below
the surface with just a huge inrush of water and the problem as I see it would
be the same as trying to exit a toilet bowl while flushed!! ( We
Downunder always revert to toilet humour) However I do remember
seeing an escape hood which has been successfully used from about 600 ft I
believe was the figure claimed. However being a diver myself and having
been down to 185 ft with Scuba it’s a hell of a long way up without
fins. I would be interested in how the hood actually functions. I
understand it has a small pony bottle but don’t know what capacity. I think that flooding through a valve
would give time to equalize your ears and provided you had your head close to
the top the air would be compressed by the flooding of the water to the point
where you would need to submerge your head and start with the breathing
apparatus. We should work out what the time frames should be as if the
size of valve is stipulated then it could be worked out. The hood idea is
the best as expelled air can be rebreathed and a constant flow of replenishing
would give buoyancy to the hood etc etc. Interesting but scary. http://www.silvercrestsubmarines.co.uk/news.html
is the link to see the escape suits. Just hope we never get into that
circumstance. Regards Hugh |