[PSUBS-MAILIST] onboard gear

MerlinSub@t-online.de via Personal_Submersibles personal_submersibles at psubs.org
Sat Apr 27 10:00:28 EDT 2019


Alan there is a desinfection liquid for Hospital breathing mask, Gasmask 
and diver rebreather.
You can use it to clean the BCD after using it for scuba diving.
 
As emergency devices I would simple recommend simple use an unused new BCD.
 
Desinfection like something like these here:
https://www.google.com/search?q=desinfektionsmittel+rebreather&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj3jtaUtPDhAhVBU1AKHeNXBR4Q_AUIDygC&biw=1130&bih=825
<https://www.google.com/search?q=desinfektionsmittel+rebreather&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj3jtaUtPDhAhVBU1AKHeNXBR4Q_AUIDygC&biw=1130&bih=825>
 
But at least a dive course were they training the emergency exit will also 
much help to bring you to the safer side.
My deepest emergency surfaceing without a gear was from 24 meters (abt 80 
feet)  - my rebreather stalled.
My deepest emergency surfaceing with scuba gear was from 42 meter 
(138feet),  a sharp steel from the wreck of a WWII GB Submarine destroy my 
dry suit on one leg side and it start very cold and fast flooding. Lucky no 
bents or other issues after all  - just exhaust.
So I have some training with BCB, Dive gears and Steinke Hoods.
If I should select I would first try the Steine Hood, than the BCD and at 
last a small scuba gear. Simple becuas the scuba gear gives you no extra 
bouancy. But this is my personal chooise. Other guys may have other 
preferences.
 
 
 
 
 
-----Original-Nachricht-----
Betreff: Re: [PSUBS-MAILIST] onboard gear
Datum: 2019-04-27T02:15:15+0200
Von: "Alan via Personal_Submersibles" <personal_submersibles at psubs.org>
An: "Personal Submersibles General Discussion" 
<personal_submersibles at psubs.org>
 
 
 
 
Carsten,
yes you could rely on air out of your BCD but it is not regarded as a good
practice because of disinfectants used to clean out BCDs. You would need
to find a suitable sterilising product. But this is an emergency!
I think maybe, as I have said, an escape plan for every 100 ft based on the
volume of your sub, how quickly you can flood it, how quickly you can 
equalise
your ears & what mixed gas you need to avoid getting narced, bent & O2
Poisoning. Beyond certain depths you would need to start breathing mixed 
gas from a pony bottle or whatever as the hull equalised.
Now you have me thinking!!! What about an external scuba tank full of mixed
gas plumbed through to the cabin to breath from during the flooding of the 
hull,
this would give you a lot more time to equalise your ears! Plumb this tank 
to
act as a reserve ballast blow so it is not wasted. Leave the sub with the 
pony
bottle full of mixed gas & inflate the horseshoe BCD with it, then breath 
from
the BCD.
Alan
 
 

On 27/04/2019, at 9:45 AM, MerlinSub at t-online.de
<mailto:MerlinSub at t-online.de> via Personal_Submersibles <
personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > 
wrote:


    Alan the pony is just for the first filling the vest in the moment you
    leave the sub.
    During the fast as possible way to the surface the air in the vest
    expand all the
    time and leave via the overpressure valve. 
     
    Imagine you have a vest of say 4 Liter. How much air will be in if you
    leave the sub in 100 meter deeps?
    Right - around 40 liters. During your way to the surface 36 liters will
    leave via the overpressure vale.
    Pretty much air to breath. The pony bottle is just there for the first
    filling- so you have not to fill tthe
    vest wih your lungs because this is exhaust gas and the process may
    exhaust you also.
     
    A filled 220 bar by  0,5 Liter pony bottle contains 110 liter expand
    gas.
    If we assume the vest has 4 Liters volume you can fill the vest up to a
    depth equal to 27 bar or 270 meter dephts.
    And you can breath all these 110Liter air from the vest except the last
    4 liters which you need on the surface
    for bouancy.
     
    In real life it is may better first to leave the sub and than open the
    valve to fill the vest.
    Otherwise it makes you more bulky and you have the possibility to
    scratch the vest somewere on your sub exit.
     
    If you have no expiernce with such vest you should traning it in a 2-4
    meter depth pool to get an feeling for it.
     
    On Euronaut we have all that gear on board. Scuba vest, Steinke hoods
    and dive gear including suits.
     
    On a emergency exit of a sunen military argentinna submarnne which was
    sunken in the 80ies or 90ies some crew members manage to escape from 40
    meter depth. The guys with the Steinke Hoods and no dive expierence
    survifed all.
    The colleges with the scuba expierence use the dive gears - help the
    other guys to get out -
    and died later on decompression thickness. :-(
     
     
     
     
    -----Original-Nachricht-----
    Betreff: Re: [PSUBS-MAILIST] onboard gear
    Datum: 2019-04-26T23:03:14+0200
    Von: "Alan via Personal_Submersibles" <personal_submersibles at psubs.org
    <mailto:personal_submersibles at psubs.org> >
    An: "Personal Submersibles General Discussion" <
    personal_submersibles at psubs.org
    <mailto:personal_submersibles at psubs.org> >
     
     
     
     
    Sean / all,
    the cold will certainly be a factor but you will be exposed to that for
    some
    time while the submarine fills with water & equalises. So the extra 15
    seconds
    grabbing an external tank won't be major.
    What I fear most is bursting my ear drums, & freezing water in the
    inner ear.
    I imagine this would be very painful, maybe like brain freeze, but I am
    only guessing.
    Some people have more problems than others equalising & once you start
    to
    feel pain in your ear from pressure it is more difficult to equalise.
    I think some control on the flooding speed to let you equalise your
    ears would
    be an asset. Pitty to burst your ear drums when you might be doing a
    simple
    escape from 100ft.
    As Emile & Carsten showed with their practice escapes; they could get
    out
    relatively easily, & with a bit of air ( 6 cu ft pony bottle ) you
    could get to the
    surface easy enough.
    If I were escaping from deeper I would use a pony bottle with mixed gas
    some
    time after the equivalent of 150ft & this would buy me a bit of time to
    equalise
    & save my ears, then escape & use my large mixed gas tank to go to the
    surface
    making stops if I felt able.
    There is sense in you saying Keep It Simple, but if you pre plan &
    practice, a
    more complex but safer escape is possible. Maybe work out how long it
    is going 
    to take to fill your particular sub at varying depths, how quickly you
    could equalise
    for varying depths. How long your pony bottle would last you & have a
    knowledge 
    of what stops would be best for the varying depths you may escape from.
    At least that would take away a lot of the fear of the unknown & reduce
    panic.
    BTW I am a diver & amateur speleologist so used to cold wet tight
    spaces.
    Alan
     
     
     
     

    On 27/04/2019, at 12:17 AM, Sean T. Stevenson via Personal_Submersibles
    <personal_submersibles at psubs.org
    <mailto:personal_submersibles at psubs.org> > wrote:


        Alan - Don't overthink this. A buoyant emergency ascent can get you
        to the surface in less than 60 seconds if you are not purposefully
        attempting to limit your ascent rate. How long can you hold your
        breath (not that you should)? A gas source helps you avoid a
        hypoxic blackout, but with a hood of any description you shouldn't
        drown. You'll just end up rebreathing some of the hood gas. As we
        discussed earlier, hypothermia will be an issue, as will the
        exposure time - it is actually better to get up from depth ASAP
        than to spend time messing around at depth and then having a bunch
        of stuff slowing your ascent while deep. My point about the gas
        consumption was to illustrate how impractical it would be to carry
        sufficient gas to enable an ascent as a diver would do it.

        Sean


        -------- Original Message --------
        On Apr 25, 2019, 23:39, Alan via Personal_Submersibles < 
        personal_submersibles at psubs.org
        <mailto:personal_submersibles at psubs.org> > wrote:


             
            More thoughts on escape...
            Went in to a couple of dive shops today looking at pony
            bottles.
            The smallest they were selling were 19 cu ft. I did see a 13 cu
            ft they were 
            filling. Both looked too big for my intended dual purpose use
            of a horse shoe
            BCD as a life jacked. A bit clutsy getting in to the sub
            wearing a BCD & large
            tank. They make a 6 cu ft pony bottle but I would have to
            import it & it would
            only get me to the surface from about 100ft.
            I had the thought of filling a 6 cu ft pony bottle with mixed
            gas & having an 
            80 cuft mixed gas tank outside the hull. It could have an
            octopus regulator
            ( to avoid free flow) permanently on the 80 & a quick
            disconnect fitting on it that
            a hose attaches to for use as a reserve ballast blow. 
            So you breath through your pony reg while flooding & escaping,
            then when
            outside use the 80 cu ft tank reg while detaching the ballast
            hose, attaching
            the BCD connection and un latching the tank.
            It could be practiced in the garage with your eyes closed &
            done in about 15
            seconds. Any thoughts on this?
            Alan
             

            On 26/04/2019, at 1:38 PM, Alan via Personal_Submersibles <
            personal_submersibles at psubs.org
            <mailto:personal_submersibles at psubs.org> > wrote:


                 
                Thanks Carsten,
                I am thinking I may go with something similar; a horse
                collar BCD with a
                13 cu ft pony bottle. (BCD below).
                It could double as a life jacket, has manual inflation & 
                push button inflation.
                I would have a regulator off the pony bottle as well.
                The BCD has an over inflation valve but if you wanted your
                air to last in an emergency
                you could breath expanding air out of the BCD through the
                manual inflation
                mouth piece. With a BCD as apposed to a life jacket you
                have the chance to
                slow your ascent & do a decompression stop.
                I am not sure what the maximum depth is that I could come
                up from with a 13 cu ft 
                tank.
                I could use this for shallow dives or as a supplement for
                snorkelling, so it won't be
                sitting in a sub doing nothing.
                Alan
                 
                <image1.PNG>
                 
                 

                On 25/04/2019, at 7:42 PM, MerlinSub at t-online.de
                <mailto:MerlinSub at t-online.de> via Personal_Submersibles <
                personal_submersibles at psubs.org
                <mailto:personal_submersibles at psubs.org> > wrote:


                    We figure out that the best escape equipment will be a
                    Steinke hood (hard to get now)
                    or a traditional scuba west with a small on board air
                    bottle.
                    Both give you the high lift capacity you need to make
                    an fast rise.
                    For bigger subs and cold waters light diving suits will
                    help muxh.
                     
                    Second it will  help you a lot if you allready a diver
                    or had make a course.
                     
                    We make some years ago some exercieces with a semi
                    finish Psub scuttled in a pool . 
                    First go out were really bad feelings and schock about
                    the water rush in and the cold and so.Have these in
                    mind: panic.
                    But after 3-4 times and with the knowledge it was fun
                    to do the escape exercice.
                     
                    With training and the right gear I see no problem to
                    get out of a sub even from much greater dephts.
                     
                    The releasing signal bouy should have a stopper on the
                    reel.  Otherwise a 300 m rope bouy will drived far away
                    with a sub sunken in 30 m .
                    And make the life of the rescue diver much harder. The
                    rope shall resitance the force a human can pull on it -
                    say 150 Kg at least.
                    Somebody on the surface can come to the conclusion to
                    lift the baot on these rope- better make a mark on the
                    Bouy "Sunken submarine - dont pull on the rope!"
                     
                    vbr Carsten
                     
                     
                     
                     
                    -----Original-Nachricht-----
                    Betreff: Re: [PSUBS-MAILIST] onboard gear
                    Datum: 2019-04-25T00:07:11+0200
                    Von: "Alan via Personal_Submersibles" <
                    personal_submersibles at psubs.org
                    <mailto:personal_submersibles at psubs.org> >
                    An: "Personal Submersibles General Discussion" <
                    personal_submersibles at psubs.org
                    <mailto:personal_submersibles at psubs.org> >
                     
                     
                     
                     
                    Perhaps a Psub plan for escape from down to 100ft, as
                    you could do this 
                    100 times out of 100 if you knew what you were doing.
                    Also even though most subs are capable of diving deeper
                    there is more
                    probability that entanglements like ropes & nets are
                    going to be encountered
                    In shallower depths. 
                    BTW the pressure in the sub is going to increase
                    incrementally quicker as it
                    floods & you need to keep equalising your ears like mad
                    toward the end or
                    you'll burst your ear drums, & aside from that pain,
                    will have freezing water 
                    going in to your inner ear. That would increase your
                    chances of failure.
                    Alan

                    On 24/04/2019, at 4:12 PM, Stephen Fordyce via
                    Personal_Submersibles <personal_submersibles at psubs.org
                    <mailto:personal_submersibles at psubs.org> > wrote:


                        Hi all,
                        This is an interesting discussion I've been meaning
                        to weigh in on - as an experienced tech/deep/cave
                        diver rather than a sub person.
                         
                        My feel is that unless the escapee is an
                        experienced diver (and even then), the chances of a
                        successful escape from below 50m/150ft depth are so
                        low as to be almost negligible. And I'd suggest
                        having a plan for such is (almost) an entirely
                        false sense of security - and energy should be
                        diverted elsewhere to reduce risk.
                         
                        A few of the scarier things like narcosis and the
                        bends have had a lot of airtime, but basic stuff
                        like keeping a diving mask clear (and one that's
                        probably fogging up), panic-breathing a soggy SCUBA
                        reg and dealing with the thermal shock of sudden
                        immersion are likely to cause death by drowning
                        much earlier. Don't underestimate the thermal shock
                        and how useless it makes you with no exposure suit.
                        Breathing a regulator without a mask is a skill in
                        itself. You're probably already suffering from
                        fatigue, stress, high CO2 and/or low O2 from
                        waiting for rescue and getting to such a desperate
                        point. All of these cause significant mental
                        impairment before you even start on the escape.
                         
                        Forget about planning to hold stops on the way up,
                        switch gases or do decompression. Even if you're
                        lucky enough to still be conscious and thinking in
                        the latter stages of the rapid ascent, personal
                        buoyancy control is unlikely to be possible.
                         
                        So if you're going to attempt to escape, I suggest
                        the best chance for survival is to plan on a very
                        simple setup (per person), buoyancy for a
                        rapid/undignified ascent, and needing urgent
                        medical attention and oxygen on the surface.  Maybe
                        carry a cylinder of trimix on board to give
                        yourself a better chance of being able to think,
                        but it's a big weight/cost premium if it's enough
                        to be useful.  Use a divers (with closed bottom)
                        "lift bag" and a loop around at the armpits as a
                        quick and easy way to get a person shooting
                        upwards. CO2 inflatable life jacket to keep
                        unconscious head above water on surface. (Inflate
                        at depth while conscious - won't fill much, but
                        will expand on way up) Might be better put towards
                        things like extra life support duration.  Consider
                        doing regular practise drills that are as realistic
                        as possible.
                         
                        Highly skilled divers mess up basic skills in
                        stressful situations and die with sad regularity.
                        Don't imagine your (and passengers) chances of
                        winging it at depth will be anything other than
                        tiny. 30m/90ft and shallower they are a bit better.
                         
                        I hate to be negative, but perhaps for deep PSUB
                        diving, the inability to escape is just one of
                        those residual risks that can be accepted for a
                        recreational activity.
                         
                        Cheers,
                        Steve Fordyce 
                        Melbourne, Australia

                        On Wed, 24 Apr 2019 10:57 hank pronk via
                        Personal_Submersibles <
                        personal_submersibles at psubs.org
                        <mailto:personal_submersibles at psubs.org> > wrote:
                           
                          I think all submarines should have an escape pod
                          or jettisoning occupant sphere.  I admit I made a
                          mistake with my escape pod by making it only for
                          one.  An easy fix that I will likely tackle, and
                          that is to stretch the pod making it big enough
                          for two.  E3000 has a jettisoning occupant
                          sphere.
                          Hank
                           
                          On Tuesday, April 23, 2019, 5:39:01 PM MDT, TOM
                          WHENT via Personal_Submersibles <
                          personal_submersibles at psubs.org
                          <mailto:personal_submersibles at psubs.org> > wrote:
                           
                           
                          A compact bail out rebreather might be the most
                          surviveable solution however it would require a
                          significant commitment in training, maintenance
                          as well as the cost of the equipment itself. I
                          personally have not been following the
                          development of bailout rebreathers, although i'm
                          aware that some are working on this. My dive
                          group relies on planning for open circuit bailout
                          in the event of rebreather failure.

                          If money is no object, I am partial to the ISC
                          Megalodon classic CCR. In terms of robustness and
                          deep water capability,  you will find none
                          better.
                          It will get you home and flies itself. It is an
                          electronic CCR which maintains PPO2 for the user.
                          This is the unit I dive myself and feel very
                          confident in.

                          KISS classics, which are a simple and reliable
                          mechanical CCR apparatus, often come up on the
                          used market in affordable price ranges.

                          Both would require significant equipment specific
                          training but would get you out of a 400 ft jam
                          with only two small cylinders and gas to spare.
                          CCR duration is driven by metabolic rate and is
                          the same irrespective of operational depth. Even
                          the lowest end units will give you an hour plus.

                          On ascent, rebreathers do require the diver to be
                          monitoring the oxygen level display in the
                          breathing loop and very likely adding oxygen
                          manually - particularly in the mCCR type on a
                          fast ascent.
                          The other benefit of this setup is that an air
                          cell for buoyancy can be integrated easily in one
                          compact package.

                          It sounds like a lot of effort for the non diver,
                          but it is a functional answer to the risks of a
                          sub disabled in deep water.
                          What is a life worth?
                          How much risk can one accept for a hobby?

                          Food for thought anyhow.

                          Get Outlook for Android <https://aka.ms/ghei36>



                          On Tue, Apr 23, 2019 at 7:34 PM -0400, "Alan via
                          Personal_Submersibles" <
                          personal_submersibles at psubs.org
                          <mailto:personal_submersibles at psubs.org> > 
                          wrote:

                             
                           
                          As an alternative to possible death or even
                          worse, the loss of your submarine,
                          I am in early stages of designing a buoy release
                          mechanism that is used
                          for surfacing safely but has an emergency beacon
                          that can be activated 
                          with an electro magnet.
                          Thoughts are to use 150 lb braid with a
                          tensioning mechanism & have an
                          automatic boat latch mechanism that can slide
                          down the braid but is fixed
                          to the buoy with instructions, "tie a long rope
                          to the ring & let down untill
                          latch attaches to submarine. Pull up"
                          The automatic latch is a device that Phil
                          described & provided a drawing for,
                          but there may be a cheap & suitable automatic
                          boat latch ( used on release
                          & retrieve on boat launching) on the market. I am
                          still searching & if anyone
                          knows of one that may be suitable I would be
                          interested.
                          Alan

                          On 24/04/2019, at 10:51 AM, Sean T. Stevenson via
                          Personal_Submersibles <
                          personal_submersibles at psubs.org
                          <mailto:personal_submersibles at psubs.org> > wrote:


                              There is a significant difference between
                              submarine escape and a planned SCUBA dive
                              with regard to both the dive profile and the
                              equipment that you can reasonably carry.  An
                              escape is more akin to what is known as a
                              buoyant emergency ascent in recreational
                              diving, where you need to get to the surface
                              yesterday and all other considerations are
                              secondary.  In this specific case, trying to
                              keep to a slow ascent rate would
                              significantly increase the incurred
                              decompression obligation that you must
                              necessarily then blow off as you ascend
                              through the shallows, introducing an even
                              greater risk.  You also have the hypothermia
                              issue to deal with if you are not equipped
                              with exposure protection specifically
                              intended for submersion at depth. Being cold
                              reduces decompression effectiveness. In order
                              to keep to a target ascent rate or perform
                              decompression stops, you would need diving
                              instrumentation (depth gauge and timer),
                              would need the skills and experience to
                              perform gas switches and hold stops, and
                              would need significantly more bulky equipment
                              to have enough gas to perform a proper
                              decompression (slow ascent, gas switches,
                              etc.).
                               
                              When I dive to these depths on SCUBA, I wear
                              twin cylinders (>100 cu. ft. each) on my back
                              with the bottom gas (10/70 or whatever for
                              the planned depth and time), plus three or
                              four off-board cylinders (80s) carrying the
                              decompression gases (typically 21/35, 35/25,
                              EAN50 and oxygen), plus a small bottle of
                              argon for drysuit inflation.  Obviously, as
                              an escapee you are not so equipped.  Far
                              better to lockout as quickly as possible and
                              rapidly ascend (with buoyant assist) to get
                              clear of those depths where you are ongassing
                              the most, and if at all possible, to slow the
                              ascent as you approach the surface, and then
                              have your surface support or emergency
                              responders administer oxygen as transport is
                              arranged to recompression.  To be clear, an
                              emergency escape from a disabled submarine at
                              these depths is not even remotely a good idea
                              - it is simply a marginally better idea than
                              dying on the bottom.
                               
                               
                               
                              To illustrate, if you were to attempt a
                              continuous ascent from 300 fsw, the average
                              depth is 150 fsw, which is about 5.5
                              atmospheres absolute.  If you assume a
                              surface air consumption rate of 1 cu. ft. /
                              minute (high, but typical of a diver who is
                              stressed or working hard, which is inevitable
                              in a submarine escape scenario), that
                              corresponds to 5.5 cu. ft. / min at the
                              average depth of the ascent.  At a 30 ft/min
                              ascent rate, that's 10 minutes, or 55 cu. ft.
                              of gas consumed just for the continuous
                              ascent with no decompression stops, without
                              consideration for the gas consumed while
                              blowing down and locking out.  You can judge
                              for yourself the practicality of carrying an
                              80 on a PSub sized vessel just for emergency
                              escape purposes.
                               
                              Sean
                               
                              ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
                              On Tuesday, April 23, 2019 12:32 PM, David
                              Colombo via Personal_Submersibles <
                              personal_submersibles at psubs.org
                              <mailto:personal_submersibles at psubs.org> >
                              wrote:
                               

                                  Hi Guys, This topic is fascinating and
                                  scary at the same time. Accent rates form
                                  the old Navy logs had 60ft / minute max
                                  with a recommended max accent rate of 30
                                  ft/ min. At 300ft escape depth, what
                                  volume of mixed gases would you need for
                                  a 10 minute accent assuming you choose
                                  not to swim 60ft/min.
                                   
                                  Best Regards,
                                  David Colombo
                                  804 College Ave
                                  Santa Rosa, CA. 95404
                                  (707) 536-1424
                                  www.SeaQuestor.com
                                  <http://www.SeaQuestor.com>

                               

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                          As an alternative to possible death or even
                          worse, the loss of your submarine,
                          I am in early stages of designing a buoy release
                          mechanism that is used
                          for surfacing safely but has an emergency beacon
                          that can be activated 
                          with an electro magnet.
                          Thoughts are to use 150 lb braid with a
                          tensioning mechanism & have an
                          automatic boat latch mechanism that can slide
                          down the braid but is fixed
                          to the buoy with instructions, "tie a long rope
                          to the ring & let down untill
                          latch attaches to submarine. Pull up"
                          The automatic latch is a device that Phil
                          described & provided a drawing for,
                          but there may be a cheap & suitable automatic
                          boat latch ( used on release
                          & retrieve on boat launching) on the market. I am
                          still searching & if anyone
                          knows of one that may be suitable I would be
                          interested.
                          Alan

                          On 24/04/2019, at 10:51 AM, Sean T. Stevenson via
                          Personal_Submersibles <
                          personal_submersibles at psubs.org
                          <mailto:personal_submersibles at psubs.org> > wrote:


                              There is a significant difference between
                              submarine escape and a planned SCUBA dive
                              with regard to both the dive profile and the
                              equipment that you can reasonably carry.  An
                              escape is more akin to what is known as a
                              buoyant emergency ascent in recreational
                              diving, where you need to get to the surface
                              yesterday and all other considerations are
                              secondary.  In this specific case, trying to
                              keep to a slow ascent rate would
                              significantly increase the incurred
                              decompression obligation that you must
                              necessarily then blow off as you ascend
                              through the shallows, introducing an even
                              greater risk.  You also have the hypothermia
                              issue to deal with if you are not equipped
                              with exposure protection specifically
                              intended for submersion at depth. Being cold
                              reduces decompression effectiveness. In order
                              to keep to a target ascent rate or perform
                              decompression stops, you would need diving
                              instrumentation (depth gauge and timer),
                              would need the skills and experience to
                              perform gas switches and hold stops, and
                              would need significantly more bulky equipment
                              to have enough gas to perform a proper
                              decompression (slow ascent, gas switches,
                              etc.).
                               
                              When I dive to these depths on SCUBA, I wear
                              twin cylinders (>100 cu. ft. each) on my back
                              with the bottom gas (10/70 or whatever for
                              the planned depth and time), plus three or
                              four off-board cylinders (80s) carrying the
                              decompression gases (typically 21/35, 35/25,
                              EAN50 and oxygen), plus a small bottle of
                              argon for drysuit inflation.  Obviously, as
                              an escapee you are not so equipped.  Far
                              better to lockout as quickly as possible and
                              rapidly ascend (with buoyant assist) to get
                              clear of those depths where you are ongassing
                              the most, and if at all possible, to slow the
                              ascent as you approach the surface, and then
                              have your surface support or emergency
                              responders administer oxygen as transport is
                              arranged to recompression.  To be clear, an
                              emergency escape from a disabled submarine at
                              these depths is not even remotely a good idea
                              - it is simply a marginally better idea than
                              dying on the bottom.
                               
                               
                               
                              To illustrate, if you were to attempt a
                              continuous ascent from 300 fsw, the average
                              depth is 150 fsw, which is about 5.5
                              atmospheres absolute.  If you assume a
                              surface air consumption rate of 1 cu. ft. /
                              minute (high, but typical of a diver who is
                              stressed or working hard, which is inevitable
                              in a submarine escape scenario), that
                              corresponds to 5.5 cu. ft. / min at the
                              average depth of the ascent.  At a 30 ft/min
                              ascent rate, that's 10 minutes, or 55 cu. ft.
                              of gas consumed just for the continuous
                              ascent with no decompression stops, without
                              consideration for the gas consumed while
                              blowing down and locking out.  You can judge
                              for yourself the practicality of carrying an
                              80 on a PSub sized vessel just for emergency
                              escape purposes.
                               
                              Sean
                               
                              ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
                              On Tuesday, April 23, 2019 12:32 PM, David
                              Colombo via Personal_Submersibles <
                              personal_submersibles at psubs.org
                              <mailto:personal_submersibles at psubs.org> >
                              wrote:
                               

                                  Hi Guys, This topic is fascinating and
                                  scary at the same time. Accent rates form
                                  the old Navy logs had 60ft / minute max
                                  with a recommended max accent rate of 30
                                  ft/ min. At 300ft escape depth, what
                                  volume of mixed gases would you need for
                                  a 10 minute accent assuming you choose
                                  not to swim 60ft/min.
                                   
                                  Best Regards,
                                  David Colombo
                                  804 College Ave
                                  Santa Rosa, CA. 95404
                                  (707) 536-1424
                                  www.SeaQuestor.com
                                  <http://www.SeaQuestor.com>

                               

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