[PSUBS-MAILIST] onboard gear

Wed Apr 24 02:22:08 EDT 2019

I do not speak with the same authority as Steve (being an experienced
technical diver and all) but in my own opinion, the idea of bailing out of
a sub at ANY depth seems crazy. In my own mind, I've always likened U/W
escape to wearing a parachute while flying in an airplane. Yes,
theoretically in some situations it will save you, but practically speaking
it seems like more of a false sense of security than a practical solution
for survival. Then again, if your situation is so dire that you're about to
die anyway, might as well give it a shot. Personally, I would rather
believe someone on the surface is going to be able to perform a rescue with
lift bags where I can get back to the surface dry. ~ Doug

On Wed, Apr 24, 2019 at 12:13 AM Stephen Fordyce via Personal_Submersibles <
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> 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> 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> 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> 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> 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
>>
>>
>> _______________________________________________
>> Personal_Submersibles mailing list
>> Personal_Submersibles at psubs.org
>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>
>>
>> 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> 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> 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
>>
>>
>> _______________________________________________
>> Personal_Submersibles mailing list
>> Personal_Submersibles at psubs.org
>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>
>> _______________________________________________
>> Personal_Submersibles mailing list
>> Personal_Submersibles at psubs.org
>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>> _______________________________________________
>> Personal_Submersibles mailing list
>> Personal_Submersibles at psubs.org
>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>> _______________________________________________
>> Personal_Submersibles mailing list
>> Personal_Submersibles at psubs.org
>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
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