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qprdave
20-06-2009, 14:42
One for Ivor (or any bubbles)

Whilst reading about a dive on the Hood I came across, "if you release the air from your stab jacket"

What is a stab jacket and what did the statement mean?

ivorthediver
20-06-2009, 16:53
One for Ivor (or any bubbles)

Whilst reading about a dive on the Hood I came across, "if you release the air from your stab jacket"

What is a stab jacket and what did the statement mean?


My turn to help you Dave.......

A Stab Jacket is a slang word for your "Buoyancy Control Device" that you wore for Diving to adjust your buoyancy depending on what depth you are at or wish to go to ....like fish have ...to do the same thing but there's is part of there anatomy
Some Diving organizations call them BCD's others call them Stabilizer jackets ...and they are shaped like a waist coat which can be inflated/ deflated by pressing a button to fill them or pulling the lead to deflate them
Depending on the make and type it can have either one or two bladders inside and they are fed from your 1st stage of your SCUBA gear.
This is a pressure regulator device which fits on top of your Air cylinder and can have from 4 to 6 leads going to supply various pieces of equipment.

It is normal practice now days to have a Main regulator from which you breath from ,a buddy regulator, to use for emergency assistance to your Diving buddy should his/hers develop a fault whilst down, a Tank contents gauge to keep an eye on the amount of air left in your cylinder, a bcd lead
to supply air to your "Stab Jacket" and if wearing a "Dry Suit" a lead to supply air to it ...unlike the wet suits which allows water to flow beneath the neoprene layer and gets trapped forming a thermal layer of warm water heated by your body...
The cylinder supplying this air would hold [in the case of a 12L cylinder ]approx 2738 Litres of compressed air at 210 Bar...if my memory serves me correctly
The reference to "releasing air from your Stab Jacket" would imply that he was adjusting his buoyancy to go up or down :)

Hope that helps you to understand what the individual was trying to do

qprdave
20-06-2009, 18:10
Thanks for that Ivor

I was talking about the Hood and he seemed to be indicating how easy it was to locate it. He said that all you need to do is be over the top and realease air from the stab jacket and there it is.

ivorthediver
20-06-2009, 18:42
Thanks for that Ivor

I was talking about the Hood and he seemed to be indicating how easy it was to locate it. He said that all you need to do is be over the top and realease air from the stab jacket and there it is.


Glad it helped Dave...

Kevin123
21-06-2009, 22:11
A Question for Ivor. A few years ago one of my friends was training to be a civilian diver, I remember he had to have his fillings replaced. Was this due to the pressure which he faced underwater. Kevin.

ivorthediver
22-06-2009, 05:00
A Question for Ivor. A few years ago one of my friends was training to be a civilian diver, I remember he had to have his fillings replaced. Was this due to the pressure which he faced underwater. Kevin.


I am not medically qualified to answer that , however this happened to me on one occasion after having a filling and soon after going on a series of deep dives and suffering from terrible blinding headaches and toothache .
I went back to my dentist who tried to reach Auz via my jawline and re-did
the filling which seemed to clear the problem I am glad to say.

I have since heard that it is quite a common event ......and a painful experience .....and expensive as well

Kevin123
25-06-2009, 00:22
Thanks Ivor, The same thing happened to an ex BP diver I know. As you said painfull and expensive. Kevin.

ivorthediver
25-06-2009, 05:22
Thanks Ivor, The same thing happened to an ex BP diver I know. As you said painfull and expensive. Kevin.


Your very welcome ...any time

Rob Hoole
25-06-2009, 07:32
A Question for Ivor. A few years ago one of my friends was training to be a civilian diver, I remember he had to have his fillings replaced. Was this due to the pressure which he faced underwater. Kevin.

A 'leaky filling' pressurises with air as a diver descends. The leak can then 'plug' itself as the diver ascends because of the increasing air pressure within the hollow under the filling compared to the reducing external 'ambient' pressure. If the pressure builds up to the point where it blows out the filling, you can imagine the possible effect.

As defined by Boyle's Law, any gas trapped and unable to expand at 50m depth will have six times as much pressure (i.e. try to occupy six times the volume) when it reaches the surface. Even rising from 10m to the surface will cause a doubling of gas volume which is why people ascending through the water, even from relatively shallow depths, shouldn't hold their breath.

Rob Hoole
www.mcdoa.org.uk (http://www.mcdoa.org.uk)

HMS Bergamot
25-06-2009, 08:06
The phenomenon is known as a "reverse squeeze". Fillings can cause problems, but the more common cause is a diver with a cold taking decongestants before diving. He builds up the pressure (by equalising) in his inner ears as he descends, and then, whilst at the bottom his decongestant expires without him knowing and his eustachian tubes clog back up. He's now got a higher pressure internally than externally as he rises, and that has got to hurt!

Treatment with a reverse squeeze is to descend again until the pain relieves, and then ascend more slowly (Like that's gonna work, huh!).

BTW, I think the Hood discussed is in the southern entrance of Weymouth Harbour. She upside down in about 12 m of water, but I thought she had got so tatty that diving had been banned on her?? Anyways, she's an old Victorian ironclad. We've used her in the mystery ship quiz a few months back, IIRC, if you want to see piccies.

ivorthediver
25-06-2009, 19:02
A 'leaky filling' pressurises with air as a diver descends. The leak can then 'plug' itself as the diver ascends because of the increasing air pressure within the hollow under the filling compared to the reducing external 'ambient' pressure. If the pressure builds up to the point where it blows out the filling, you can imagine the possible effect.

As defined by Boyle's Law, any gas trapped and unable to expand at 50m depth will have six times as much pressure (i.e. try to occupy six times the volume) when it reaches the surface. Even rising from 10m to the surface will cause a doubling of gas volume which is why people ascending through the water, even from relatively shallow depths, shouldn't hold their breath.

Rob Hoole
www.mcdoa.org.uk (http://www.mcdoa.org.uk)

Absolutely correct Rob join us in "The Wardroom"

ivorthediver
25-06-2009, 19:12
The phenomenon is known as a "reverse squeeze". Fillings can cause problems, but the more common cause is a diver with a cold taking decongestants before diving. He builds up the pressure (by equalising) in his inner ears as he descends, and then, whilst at the bottom his decongestant expires without him knowing and his eustachian tubes clog back up. He's now got a higher pressure internally than externally as he rises, and that has got to hurt!

Treatment with a reverse squeeze is to descend again until the pain relieves, and then ascend more slowly (Like that's gonna work, huh!).

BTW, I think the Hood discussed is in the southern entrance of Weymouth Harbour. She upside down in about 12 m of water, but I thought she had got so tatty that diving had been banned on her?? Anyways, she's an old Victorian ironclad. We've used her in the mystery ship quiz a few months back, IIRC, if you want to see piccies.


Well done Richard and spot on ...I am impressed that you remembered the correct term and spelling for the eustachian tube

Regarding the treatment for reverse squeeze I seem to remember the reverse .........and you ascended a metre and waited a little while THEN descended slowly down again it always worked for me mate....

qprdave
25-06-2009, 19:16
Ivor
Stop patronising the members. Get back in the wardroom. There is trouble with Little h and the stewards!!!!!

Kevin123
27-06-2009, 20:19
I've got another question for the divers. My grandads were both cooks and gunners, one army and one navy. Do divers have two jobs aswell and if so which one would be their main job. Kevin.

qprdave
27-06-2009, 21:11
When I was in the Navy, there were two types of navy divers. Ships and Clearance. Ships divers were part time whilst clearance were full time.

Ships divers would be used for bottom searches and reasonable simple diving work

Clearance were the professionals and full time. The would deal with Bomb and mine disposal etc.

The divers will be able to elaborate on what I have said

ivorthediver
28-06-2009, 18:32
When I was in the Navy, there were two types of navy divers. Ships and Clearance. Ships divers were part time whilst clearance were full time.

Ships divers would be used for bottom searches and reasonable simple diving work

Clearance were the professionals and full time. The would deal with Bomb and mine disposal etc.

The divers will be able to elaborate on what I have said

You learn something every day here don't you ?

Kevin123
28-06-2009, 20:09
Thanks Aprdave, I use to watch them diving in the dockyard a few years ago. Could they actually see much under the water, especially in the basins. Kevin.

ivorthediver
28-06-2009, 20:16
Thanks Aprdave, I use to watch them diving in the dockyard a few years ago. Could they actually see much under the water, especially in the basins. Kevin.


Hard to say and what kit they had to use

Kevin123
15-07-2009, 21:12
This is a question for Ivor really. I was wondering how much it would cost to take up sub aqua diving. Do you have to buy all your own kit or can you join a club to begin with. Kevin.

ivorthediver
16-07-2009, 05:28
This is a question for Ivor really. I was wondering how much it would cost to take up sub aqua diving. Do you have to buy all your own kit or can you join a club to begin with. Kevin.

BRITISH SUB AQUA CLUB
PROFESIONAL ASSO DIVING INSTRUCTORS..[PADI]


This Subject like many others in life is one where what ever you say some one else did it better, cheaper, quicker, etc etc:rolleyes:

Having said that I will tell you what I did.

I went to a local BSAC club and told them I was a type one insulin dependent Diabetic....could I learn to Dive please .??????[ prior to his I had asked PADI and they flatly refused !]
The answer was that if I could pass the medical and prove I was a stable diabetic they would teach me to dive....
BSAC is a club run for the members by the members [World Wide]
Padi is an American based business [also world wide]

The courses are structured differently and in my opinion the BSAC course offers a more comprehensive module in each section than Padi per stage of training and Padi were a lot more expensive to get to Instructor level [if that is where you wanted to get]

When I totaled up what it had cost [B]me to get to Dive Leader it was 800.00..... to get to a DIVE MASTER ...the padi ecquivilent was three times as much.

If you doubt any of this ask your local Dive club or padi school to detail each step in there training to get to DIVE LEADER OR DIVEMASTER
AND HOW MUCH

In both training programes you use their equipment to get up to your first open water dive qualification ...after that you build up your own kit as you go and depending on what level you chose to get to

Most PADI divers I knew did a cross over training programe when they reached DIVEMASTER....... to become a BSAC DIVE LEADER as it meant tha they could Legaly go down to 50m ....as the padi depth restriction for DIVEMASTERS is 40m bearing in mind that most diving insurance company's state that if you have an accident below your diving agency MAX depth rating you invalidate your insurance.

whoever you decide to go to find out up front HOW MUCH and how long to get to the level you wish to attain and bear in mind that padi is a business ...not a Club.

When I was doing Training the steps were ......Club Diver 230.00
Sports Diver 200.00
Dive Leader 200.00

But that don't add up to 800.00 Ivor Assist Club Instructor 170.00

I did my training in the early 90s so prices may be slightly out of date so check first......
Hope this helps you ...but beware Diving is addictive..........:D

Francis Stanley
16-07-2009, 12:05
When I was in the Navy, there were two types of navy divers. Ships and Clearance. Ships divers were part time whilst clearance were full time.

Ships divers would be used for bottom searches and reasonable simple diving work

Clearance were the professionals and full time. The would deal with Bomb and mine disposal etc.

The divers will be able to elaborate on what I have said

Dave

You are correct in what you say
however now there are no more Ships divers, they have been disbanded (Mainly cost driven, surprise, surprise)
There is now only the full time diving branch - they have even dropped the title "Clearance" as there is no one else to confuse it with

ivorthediver
16-07-2009, 20:37
Its the wrong environment to take risks in as we both know....

Kevin123
16-07-2009, 23:57
Thanks Ivor, There's a sub aqua club near me at Portsdown hill, I've often wondered how they go about things. I've been looking at things to try with my son. Kevin.

ivorthediver
17-07-2009, 04:59
Thanks Ivor, There's a sub aqua club near me at Portsdown hill, I've often wondered how they go about things. I've been looking at things to try with my son. Kevin.



Best thing I ever did.....and one common thing which was apparent in all the people I trained ....was confidence in the water ......and with themselves to

All my family are trained divers two BSAC and two Padi so I can't be accused of being Biased except the route to there Knowledge perhaps

Both offer things to diving ...its a matter of finance and end goal in life

Francis Stanley
17-07-2009, 07:47
Its the wrong environment to take risks in as we both know....

It certainly is,
todays RN divers are activly involved in places as far afield as Afghanistan, the Bomb and Mine disposal role has taken on even more priority than it has in the past few years. With the manpower shortages now prevelent in the services, teams are taking on roles that in the past would have been left to the Army. On top of that the teams are still expected to carry on with the usual Maritime diving support and bomb disposal commitments around uk with the same amount of manning levels as before. The dive school is flat out trying to keep numbers up as we lose disenchanted divers to the Commercial world.

Paddy
17-07-2009, 10:44
Best thing I ever did.....and one common thing which was apparent in all the people I trained ....was confidence in the water ......and with themselves to

All my family are trained divers two BSAC and two Padi so I can't be accused of being Biased except the route to there Knowledge perhaps

Both offer things to diving ...its a matter of finance and end goal in life

Hi Ivor.
Been off line for a while, ( her indoors likes going away ).
I never had any confidence in the water but loads of it under the water.
Reason being I was then 13 lbs negative so needed no weights.
Even in the sea when I breathed out I sunk like a stone.
Had to make allowances by whearing two sub sweaters.
I did not have a great deal of fat in those days, maybe I displace less now.
Paddy.

ivorthediver
17-07-2009, 20:09
Hi Ivor.
Been off line for a while, ( her indoors likes going away ).
I never had any confidence in the water but loads of it under the water.
Reason being I was then 13 lbs negative so needed no weights.
Even in the sea when I breathed out I sunk like a stone.
Had to make allowances by whearing two sub sweaters.
I did not have a great deal of fat in those days, maybe I displace less now.
Paddy.


You lucky sod , I had to carry 8 kilo around with me