Re: OT submarines
--- In bolger@y..., Stan Muller <smuller@i...> wrote:
Some considerations folks. First of all if the hose used to supply
air to the sub is not stiff enough the air pumped to the sub will
have to be copressed enough to overcome 2 atmospheres of pressure.
That is what you have at 30'. You CANNOT stay as long as you want at
30' without decopreesion. You can stay about 8 hours though which
may be the same thing. The bends are not the most dangerous
situation at 30'. They are just what the movies talk about. The
real danger from 30' is embolism,which is a condition that can
theoretcally ocurr in as little as 3'. Embolism ocurrs when a diver
ascends holding their breath after breathing in compressed air. This
is what could ocurr in a free ascent. The aveoli in the lungs can't
expand enough to match the expanding gas in them and they burst
releasing a bubble into the blood stream. This bubble will then stop
somewhere and most often it is in the brain and kill you. If you
rise slow enough on scuba gear or exhale all of the way to the
surface this can be avoided. I was once a professional diver. Milton
> Thanks guys, I appreciate your concern.
> I'll touch lightly on a few points you brought up, Before anybody
goes
> into the sub, it is pressure tested to twice what you will be using
it
> at. Since it will be on a tether, it will be limited by the tether
> length. No matter what the hull tests at, it will never go below the
> second atmosphere of 30 feet. The way you insure that, is never use
the
> sub where it is deeper than 30 feet. That is where all the
interesting
> stuff is and you still have enough light to take pictures of it.
> The breathing air is supplied by way of the tether (umbilical)
from
> the boat. There is also a full single tank aqua lung on board for
> emergencies, and a 1/4 size tank for a wet exit from the sub. The
sub
> has a 2" flood valve to relieve the interior pressure in case of
wanting
> a submerged exit. The main ballast, about 1000 pounds has a dump
lever
> inside the sub. You pull the lever, and pray you aren't under the
> tender. ;-) The main hatch is open able from inside or outside. The
main
> reasons I went to the umbilical design were #1) I'm basically
chicken,
> #2) I don't have to have all the fancy breathing apparatus on board
and
> #3) No batteries, acid, or sparks on board. I may be a few fish
short of
> a school, but I aint suicidal. ;-) I was certified for scuba back
when I
> was in the navy, so I had some idea of what I was up against when I
> started the Diving Duck and there was no way I could have
accomplished
> it on my own.
> I have to admit, I was not smart enough to figure all of this
out,
> but if you go to;
>http://www.psubs.org/and check out "Certification" and "Design
> Guidelines" you will see where my smarts came from. ;-) Plus they
are a
> great bunch of guys there willing to help out newcomers, and helped
they
> have. Check out the "gallery" while your there and see what the real
> ones look like. Very Cool.
> Stan in Mo.
> PS: when I started my sub, my wife was the first to suggest a name
for
> it. I decided on Diving Duck instead. She wanted to call it, "dope
on a
> rope". She can be Soooo unkind at times. ;-)
Hi Michael,
video of the implosion and the lecture circuit on sub safety. ;-) It's a
no loose situation.
atmosphere
and not have to decompress. Also, since these subs have one atmosphere
on the interior, you could go to what ever depth, spend as much time as
you want, and still not need to decompress, because you have been at one
atmosphere. In a wet sub, you do have to worry about decompression, not
in a dry sub. Nor do you need to decompress if you are leaving a sub at
a greater depth. When I volunteered for sub duty in the navy, one of the
things we had to do was go to the surface of a tall tank warring a
Manson lung (I think that is what it was called). I don't remember how
deep it was, but looking at how I felt at the time, it seemed like a
mile or more. ;-)
Hi Mark,
cfm at 60 pounds pressure. It will be hosed to the sub, and an exit hose
back to the surface.
Hi Lincoln,
use my compressor to draw and hold as much of a vacuum on the interior
as possible, then sink it to the 45 feet. The beauty of not knowing what
your doing is that you tend to over engineer. If I can pull and hold 20
inches of vacuum on the interior, then go to 45 feet, what does that
amount to as to total test depth? I figure, if it holds that, it sure
will be safe at 30' or less.
Thanks all for your comments, Stan in Mo.
> These type of test (refered to as hydrostatic) can be very dangerous.Other than lost work, which would be more than made up for by the
> If the hull fails it will be like a bomb going off.
video of the implosion and the lecture circuit on sub safety. ;-) It's a
no loose situation.
> If INope, As Mark, Lincoln and TOMB pointed out, roughly 30' = one
> remember right the pressure goes up by one atmosphere for every 8 ft
> of depth, so at 30 ft the pressure would be about 3.75 atmosphers or
> around 55 psi.
atmosphere
> At these pressures theNope again, At 30' or less, you can spend as much time as you want
> crew
> will have to decompress or they will get the bend
> do to nitrogen in the blood. You would be better off if the crew use
> suba and the sub was flooded. The method is very common in small subs.
> The bend would still be a possible problem.
>
and not have to decompress. Also, since these subs have one atmosphere
on the interior, you could go to what ever depth, spend as much time as
you want, and still not need to decompress, because you have been at one
atmosphere. In a wet sub, you do have to worry about decompression, not
in a dry sub. Nor do you need to decompress if you are leaving a sub at
a greater depth. When I volunteered for sub duty in the navy, one of the
things we had to do was go to the surface of a tall tank warring a
Manson lung (I think that is what it was called). I don't remember how
deep it was, but looking at how I felt at the time, it seemed like a
mile or more. ;-)
Hi Mark,
> What are you using to pump the airI have an oilless two cylinder electric compressor that puts out 5
> mixture
> to your sub?
cfm at 60 pounds pressure. It will be hosed to the sub, and an exit hose
back to the surface.
Hi Lincoln,
> Not if he tests it by dangling it in the water, as is implied. THeSince I am limited to 45 feet depth in my test pond, I had planed to
> other trick, if you're putting positive pressure, is to fill vessel
> with relatively incompressible fluid like water, then there is no
> bomb. But no need for that here.
use my compressor to draw and hold as much of a vacuum on the interior
as possible, then sink it to the 45 feet. The beauty of not knowing what
your doing is that you tend to over engineer. If I can pull and hold 20
inches of vacuum on the interior, then go to 45 feet, what does that
amount to as to total test depth? I figure, if it holds that, it sure
will be safe at 30' or less.
Thanks all for your comments, Stan in Mo.
One atmosphere = 14.7 psi = 33.93 feet of water
----- Original Message -----
From: "Michael Surface" <msurface@...>
To: <bolger@yahoogroups.com>
Sent: Thursday, July 12, 2001 3:06 PM
Subject: Re: [bolger] Re: OT submarines
>
>
>
> >From: Stan Muller <smuller@...>
> >Before anybody goes into the sub, it is pressure tested to twice what
>you
> >will be using it at.
>
> These type of test (refered to as hydrostatic) can be very dangerous.
> If the hull fails it will be like a bomb going off.
>
> >No matter what the hull tests at, it will never go below the second
> > >atmosphere of 30 feet.
>
> I have a question, what pressure are you planning to test the hull at?
> >From your remarks I gather that you think that the pressure on the hull
> would be two atmospheres or around (29.4 psi). At a depth of
> 30 ft the pressure on the hull would be higher than that. If I
> remember right the pressure goes up by one atmosphere for every 8 ft
> of depth, so at 30 ft the pressure would be about 3.75 atmosphers or
> around 55 psi. This would make your test pressure 110 psi (danger).
> You will find that at this depth you will need to provide pressure to the
> sub of 55 psi or the sub will flood with water. At these pressures the
crew
> will have to decompress or they will get the bend
> do to nitrogen in the blood. You would be better off if the crew use
> suba and the sub was flooded. The method is very common in small subs.
> The bend would still be a possible problem.
>
> Michael Surface
>
>
> _________________________________________________________________
> Get your FREE download of MSN Explorer athttp://explorer.msn.com
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, or spamming
> - no flogging dead horses
> - add something: take "thanks!" and "ditto!" posts off-list.
> - stay on topic and punctuate
> - add your comments at the TOP and SIGN your posts
> - To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
01930, Fax: (978) 282-1349
>
>
> Your use of Yahoo! Groups is subject tohttp://docs.yahoo.com/info/terms/
>
>
see below. I still want to know about the Bolger sub. Or is it
apocryphal?
apocryphal?
--- In bolger@y..., "Michael Surface" <msurface@h...> wrote:
> >From: Stan Muller <smuller@i...>
> >Before anybody goes into the sub, it is pressure tested to twice
what >you
> >will be using it at.
>
> These type of test (refered to as hydrostatic) can be very
dangerous.
> If the hull fails it will be like a bomb going off.
Not if he tests it by dangling it in the water, as is implied. THe
other trick, if you're putting positive pressure, is to fill vessel
with relatively incompressible fluid like water, then there is no
bomb. But no need for that here.
>
> >No matter what the hull tests at, it will never go below the second
> > >atmosphere of 30 feet.
>
> I have a question, what pressure are you planning to test the hull
at?
> From your remarks I gather that you think that the pressure on the
hull
> would be two atmospheres or around (29.4 psi). At a depth of
> 30 ft the pressure on the hull would be higher than that. If I
> remember right the pressure goes up by one atmosphere for every 8 ft
> of depth, snip
No, that's not right. Stan is about right. Do the math. 62 lbs/ft3 X
30 feet/(144in2/ft2) =13psi+ambient atmospheric or around 29psi. You
could make some very shallow draft boats in that special dense water.
re other message:
No worry as to bends at 30 feet unless maybe you fly in unpressurized
plane right afterward, but the sub is supposed to be at 1 atmosphere
anyway. You could use up a lot of air pressurizing that thing, and
depth changes would be tedious.
-Lincoln Ross, former diver and former student of ocean engineering
Been awhile since I have done any diving but I do recall that at 30 feet
there is no worry as to the bends. What are you using to pump the air mixture
to your sub?
Mark
there is no worry as to the bends. What are you using to pump the air mixture
to your sub?
Mark
>From: Stan Muller <smuller@...>These type of test (refered to as hydrostatic) can be very dangerous.
>Before anybody goes into the sub, it is pressure tested to twice what >you
>will be using it at.
If the hull fails it will be like a bomb going off.
>No matter what the hull tests at, it will never go below the secondI have a question, what pressure are you planning to test the hull at?
> >atmosphere of 30 feet.
From your remarks I gather that you think that the pressure on the hull
would be two atmospheres or around (29.4 psi). At a depth of
30 ft the pressure on the hull would be higher than that. If I
remember right the pressure goes up by one atmosphere for every 8 ft
of depth, so at 30 ft the pressure would be about 3.75 atmosphers or
around 55 psi. This would make your test pressure 110 psi (danger).
You will find that at this depth you will need to provide pressure to the
sub of 55 psi or the sub will flood with water. At these pressures the crew
will have to decompress or they will get the bend
do to nitrogen in the blood. You would be better off if the crew use
suba and the sub was flooded. The method is very common in small subs.
The bend would still be a possible problem.
Michael Surface
_________________________________________________________________
Get your FREE download of MSN Explorer athttp://explorer.msn.com
Hi Lincoln and Dan,
Thanks guys, I appreciate your concern.
I'll touch lightly on a few points you brought up, Before anybody goes
into the sub, it is pressure tested to twice what you will be using it
at. Since it will be on a tether, it will be limited by the tether
length. No matter what the hull tests at, it will never go below the
second atmosphere of 30 feet. The way you insure that, is never use the
sub where it is deeper than 30 feet. That is where all the interesting
stuff is and you still have enough light to take pictures of it.
The breathing air is supplied by way of the tether (umbilical) from
the boat. There is also a full single tank aqua lung on board for
emergencies, and a 1/4 size tank for a wet exit from the sub. The sub
has a 2" flood valve to relieve the interior pressure in case of wanting
a submerged exit. The main ballast, about 1000 pounds has a dump lever
inside the sub. You pull the lever, and pray you aren't under the
tender. ;-) The main hatch is open able from inside or outside. The main
reasons I went to the umbilical design were #1) I'm basically chicken,
#2) I don't have to have all the fancy breathing apparatus on board and
#3) No batteries, acid, or sparks on board. I may be a few fish short of
a school, but I aint suicidal. ;-) I was certified for scuba back when I
was in the navy, so I had some idea of what I was up against when I
started the Diving Duck and there was no way I could have accomplished
it on my own.
I have to admit, I was not smart enough to figure all of this out,
but if you go to;
http://www.psubs.org/and check out "Certification" and "Design
Guidelines" you will see where my smarts came from. ;-) Plus they are a
great bunch of guys there willing to help out newcomers, and helped they
have. Check out the "gallery" while your there and see what the real
ones look like. Very Cool.
Stan in Mo.
PS: when I started my sub, my wife was the first to suggest a name for
it. I decided on Diving Duck instead. She wanted to call it, "dope on a
rope". She can be Soooo unkind at times. ;-)
Thanks guys, I appreciate your concern.
I'll touch lightly on a few points you brought up, Before anybody goes
into the sub, it is pressure tested to twice what you will be using it
at. Since it will be on a tether, it will be limited by the tether
length. No matter what the hull tests at, it will never go below the
second atmosphere of 30 feet. The way you insure that, is never use the
sub where it is deeper than 30 feet. That is where all the interesting
stuff is and you still have enough light to take pictures of it.
The breathing air is supplied by way of the tether (umbilical) from
the boat. There is also a full single tank aqua lung on board for
emergencies, and a 1/4 size tank for a wet exit from the sub. The sub
has a 2" flood valve to relieve the interior pressure in case of wanting
a submerged exit. The main ballast, about 1000 pounds has a dump lever
inside the sub. You pull the lever, and pray you aren't under the
tender. ;-) The main hatch is open able from inside or outside. The main
reasons I went to the umbilical design were #1) I'm basically chicken,
#2) I don't have to have all the fancy breathing apparatus on board and
#3) No batteries, acid, or sparks on board. I may be a few fish short of
a school, but I aint suicidal. ;-) I was certified for scuba back when I
was in the navy, so I had some idea of what I was up against when I
started the Diving Duck and there was no way I could have accomplished
it on my own.
I have to admit, I was not smart enough to figure all of this out,
but if you go to;
http://www.psubs.org/and check out "Certification" and "Design
Guidelines" you will see where my smarts came from. ;-) Plus they are a
great bunch of guys there willing to help out newcomers, and helped they
have. Check out the "gallery" while your there and see what the real
ones look like. Very Cool.
Stan in Mo.
PS: when I started my sub, my wife was the first to suggest a name for
it. I decided on Diving Duck instead. She wanted to call it, "dope on a
rope". She can be Soooo unkind at times. ;-)