29 Sep 2007 00:12:58
Sheldon
No wonder I can't swim

I finally did a buoyancy test at the pool with about 300 lbs of air in my
tank (steel). Since everybody here said I was too heavy I decided to test
with no weights. Inhale and I floated at eye level. Exhale and I sank.
With no weight I was perfectly buoyant! Unfortunately, since I'm a novice,
I can't control my breathing enough stay down, but it would be a great skill
to work on.

I then grabbed a three pound weight from the edge of the pool and sank ever
so slowly and touched down like a feather. Also, descending that slowly I
didn't even notice any pressure on my ears. I just got to the bottom, all
12 feet of it, with no problem.

Seems this may be why I have trouble swimming freestyle. While I can do it
now, I'm not very buoyant and it takes a bit more effort. I guess I'm less
fat than I thought I was. :-)

Sheldon




29 Sep 2007 12:45:51
Matthias Voss
Re: No wonder I can't swim

Sheldon wrote:

> I finally did a buoyancy test at the pool with about 300 lbs of air in my
> tank (steel).

That should have been a double 250 l rig, filled to 200 bar.
How do you handle that at the surface?


> Since everybody here said I was too heavy I decided to test
> with no weights. Inhale and I floated at eye level. Exhale and I sank.
> With no weight I was perfectly buoyant! Unfortunately, since I'm a novice,
> I can't control my breathing enough stay down, but it would be a great skill
> to work on.

No pun intended, but that is perfectly normal. Most people
with a steel tank will sink on exhaling, and stay afloat
only inhaled.

Matthias



> Sheldon
>
>


--
VK exquis. mod. Gesch.haus in ruh. Wohnl.3 WE, ehem. Praxis,
ca. 350/1000 qm WF/Grdst. 19km nördl. Braunschweig , hochw.
einger; Nah VW, Hafen; frei, 0160-4433698 o. 0911-7809081.
Gut für Arzt/RA/Ing.büro, oder ruhiges Wohnen, Bilder vorh.



29 Sep 2007 08:56:51
Dan Bracuk
Re: No wonder I can't swim

"Sheldon" <sheldon@XXXXXXXXsopris.net > pounded away at his keyboard
resulting in:

:I finally did a buoyancy test at the pool with about 300 lbs of air in my
:tank (steel). Since everybody here said I was too heavy I decided to test
:with no weights. Inhale and I floated at eye level. Exhale and I sank.
:With no weight I was perfectly buoyant! Unfortunately, since I'm a novice,
:I can't control my breathing enough stay down, but it would be a great skill
:to work on.

Good for you. Don't worry about not being able to stay down when you
inhale. In real life you'll have more air in your tank which will
give you more weight on your safety stop. Plus you'll be doing it at
15 - 20 feet so you'll be a little less bouyant than at the surface.

Remember the test. For dive travel you'll be in salt water with an
aluminium tank and you'll have to do it again.

Dan Bracuk
Never use a big word when a diminutive one will do.

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.comThe #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----


29 Sep 2007 09:32:02
Greg Mossman
Re: No wonder I can't swim

On Sep 29, 3:45 am, Matthias Voss <spammat.v...@gmx.de > wrote:

> > Since everybody here said I was too heavy I decided to test
> > with no weights. Inhale and I floated at eye level. Exhale and I sank.
> > With no weight I was perfectly buoyant! Unfortunately, since I'm a novice,
> > I can't control my breathing enough stay down, but it would be a great skill
> > to work on.
>
> No pun intended, but that is perfectly normal. Most people
> with a steel tank will sink on exhaling, and stay afloat
> only inhaled.

That's because most people without any gear or tank on at all will
sink on exhaling and stay afloat only inhaled, even a "big boned" guy
like me. The steel tank at 300 psi, being approximately neutrally
buoyant, doesn't add anything to the equation.



29 Sep 2007 10:35:55
Sheldon
Re: No wonder I can't swim



>
> No pun intended, but that is perfectly normal. Most people with a steel
> tank will sink on exhaling, and stay afloat only inhaled.
>
> Matthias
>

And here I thought I was special. :-(




29 Sep 2007 10:48:31
Sheldon
Re: No wonder I can't swim


"Dan Bracuk" <NOTbracuk@pathcom.com > wrote in message
news:1dmsf31p14ee4a4i0p81g8n4ar9pa2g3ts@4ax.com...
> "Sheldon" <sheldon@XXXXXXXXsopris.net> pounded away at his keyboard
> resulting in:
>
> :I finally did a buoyancy test at the pool with about 300 lbs of air in my
> :tank (steel). Since everybody here said I was too heavy I decided to
> test
> :with no weights. Inhale and I floated at eye level. Exhale and I sank.
> :With no weight I was perfectly buoyant! Unfortunately, since I'm a
> novice,
> :I can't control my breathing enough stay down, but it would be a great
> skill
> :to work on.
>
> Good for you. Don't worry about not being able to stay down when you
> inhale. In real life you'll have more air in your tank which will
> give you more weight on your safety stop. Plus you'll be doing it at
> 15 - 20 feet so you'll be a little less bouyant than at the surface.
>
> Remember the test. For dive travel you'll be in salt water with an
> aluminium tank and you'll have to do it again.
>
> Dan Bracuk

Is there a chart anywhere on the Net that give you theoretical weights for
dive gear? For example: When wearing a 5 mil wetsuit add X number of lbs.
Seems to me once you know your buoyancy in a swimsuit in fresh water you
should be able to get really close when diving in salt water or wearing a
wetsuit right from the start. Most of the books just say, "You'll need more
weight when..."

I was talking to my instructor/shop owner about diving with a 7mil wetsuit
to get into some of the reservoirs around here. Sounded like I would have
to hang an anvil around my neck.




29 Sep 2007 17:17:13
Grumman-581
Re: No wonder I can't swim

On Sat, 29 Sep 2007 10:35:55 -0600, "Sheldon"
<sheldon@XXXXXXXXsopris.net > wrote:

> And here I thought I was special. :-(

You are... They even have a type of Olympics for you... <evil-grin >


29 Sep 2007 17:30:35
Sheldon
Re: No wonder I can't swim


"Grumman-581" <grumman581@DIE-SPAMMER-SCUM-gmail.com > wrote in message
news:cmjtf3ljkeve8h1cd3d0ntjh0qkfrpvfn6@4ax.com...
> On Sat, 29 Sep 2007 10:35:55 -0600, "Sheldon"
> <sheldon@XXXXXXXXsopris.net> wrote:
>
>> And here I thought I was special. :-(
>
> You are... They even have a type of Olympics for you... <evil-grin>

Once they see me swim I'll fit right in.




29 Sep 2007 17:33:32
Sheldon
Re: No wonder I can't swim


"Greg Mossman" <mossman@qnet.com > wrote in message
news:1191083522.012710.11880@57g2000hsv.googlegroups.com...
> On Sep 29, 3:45 am, Matthias Voss <spammat.v...@gmx.de> wrote:
>
>> > Since everybody here said I was too heavy I decided to test
>> > with no weights. Inhale and I floated at eye level. Exhale and I
>> > sank.
>> > With no weight I was perfectly buoyant! Unfortunately, since I'm a
>> > novice,
>> > I can't control my breathing enough stay down, but it would be a great
>> > skill
>> > to work on.
>>
>> No pun intended, but that is perfectly normal. Most people
>> with a steel tank will sink on exhaling, and stay afloat
>> only inhaled.
>
> That's because most people without any gear or tank on at all will
> sink on exhaling and stay afloat only inhaled, even a "big boned" guy
> like me. The steel tank at 300 psi, being approximately neutrally
> buoyant, doesn't add anything to the equation.
>
But an aluminum tank at 300 psi would be positive buoyant. Correct?




29 Sep 2007 16:50:58
Greg Mossman
Re: No wonder I can't swim

On Sep 29, 4:33 pm, "Sheldon" <shel...@XXXXXXXXsopris.net > wrote:

> > That's because most people without any gear or tank on at all will
> > sink on exhaling and stay afloat only inhaled, even a "big boned" guy
> > like me. The steel tank at 300 psi, being approximately neutrally
> > buoyant, doesn't add anything to the equation.
>
> But an aluminum tank at 300 psi would be positive buoyant. Correct?

Exactly. Which means if you don't have 4 lbs or so to hold you down,
you'll rise into the air until you hit the sun.

No, just kidding. That's only if you dive on helium.



29 Sep 2007 20:16:25
Dan Bracuk
Re: No wonder I can't swim

"Sheldon" <sheldon@XXXXXXXXsopris.net > pounded away at his keyboard
resulting in:
:But an aluminum tank at 300 psi would be positive buoyant. Correct?

Correct, but not necessarly significant.

Dan Bracuk
Never use a big word when a diminutive one will do.

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.comThe #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----


29 Sep 2007 19:54:34
Sheldon
Re: No wonder I can't swim


"Dan Bracuk" <NOTbracuk@pathcom.com > wrote in message
news:s5utf3564tsrc9vd11hvlulguicmt86kcr@4ax.com...
> "Sheldon" <sheldon@XXXXXXXXsopris.net> pounded away at his keyboard
> resulting in:
> :But an aluminum tank at 300 psi would be positive buoyant. Correct?
>
> Correct, but not necessarly significant.
>
> Dan Bracuk

I read the difference is two pounds, but that may be splitting hairs. I
have read that some people prefer steel because of the neutral buoyancy as
it empties.




29 Sep 2007 21:10:21
Grumman-581
Re: No wonder I can't swim

On Sat, 29 Sep 2007 20:16:25 -0500, Dan Bracuk <NOTbracuk@pathcom.com >
wrote:

> Correct, but not necessarly significant.

Yeah, at 300 psi, you probably want to be starting to think about
surfacing and as such, being positively buoyant tends to help that a
bit...


29 Sep 2007 22:21:57
Dan Bracuk
Re: No wonder I can't swim

"Sheldon" <sheldon@XXXXXXXXsopris.net > pounded away at his keyboard
resulting in:

:I read the difference is two pounds, but that may be splitting hairs. I
:have read that some people prefer steel because of the neutral buoyancy as
:it empties.

I prefer aluminium because it is more positively bouyant. As such,
it's less of a weight on the back when diving. Also, if you turn your
body, aluminium tanks are less likely to try to flip you over.

Dan Bracuk
Never use a big word when a diminutive one will do.

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.comThe #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----


29 Sep 2007 22:23:13
Sheldon
Re: No wonder I can't swim


"Dan Bracuk" <NOTbracuk@pathcom.com > wrote in message
news:ki5uf3541r4lak8n3qs5hiip9deeumcnff@4ax.com...
> "Sheldon" <sheldon@XXXXXXXXsopris.net> pounded away at his keyboard
> resulting in:
>
> :I read the difference is two pounds, but that may be splitting hairs. I
> :have read that some people prefer steel because of the neutral buoyancy
> as
> :it empties.
>
> I prefer aluminium because it is more positively bouyant. As such,
> it's less of a weight on the back when diving. Also, if you turn your
> body, aluminium tanks are less likely to try to flip you over.
>
> Dan Bracuk

It is a handful, but I had trouble in class with the aluminum tanks. I need
to learn to control the tank and not the other way around. Doing much
better than when I started, and having a bc that fits is a big help. Don't
really notice the tank much anymore, but you make a good point. When I
travel I'll be renting.




30 Sep 2007 10:31:06
Matthias Voss
Re: No wonder I can't swim

Sheldon wrote:

> "Greg Mossman" <mossman@qnet.com> wrote in message
> news:1191083522.012710.11880@57g2000hsv.googlegroups.com...
>
>>On Sep 29, 3:45 am, Matthias Voss <spammat.v...@gmx.de> wrote:
>>
>>
>>>>Since everybody here said I was too heavy I decided to test
>>>>with no weights. Inhale and I floated at eye level. Exhale and I
>>>>sank.
>>>>With no weight I was perfectly buoyant! Unfortunately, since I'm a
>>>>novice,
>>>>I can't control my breathing enough stay down, but it would be a great
>>>>skill
>>>>to work on.
>>>
>>>No pun intended, but that is perfectly normal. Most people
>>>with a steel tank will sink on exhaling, and stay afloat
>>>only inhaled.
>>
>>That's because most people without any gear or tank on at all will
>>sink on exhaling and stay afloat only inhaled, even a "big boned" guy
>>like me. The steel tank at 300 psi, being approximately neutrally
>>buoyant, doesn't add anything to the equation.
>>
>
> But an aluminum tank at 300 psi would be positive buoyant. Correct?

Depends.Normally yes. Luxfer had a NB-Series which had lead
in the bottom. Incredibly heavy.
Matthias

--
VK exquis. mod. Gesch.haus in ruh. Wohnl.3 WE, ehem. Praxis,
ca. 350/1000 qm WF/Grdst. 19km nördl. Braunschweig , hochw.
einger; Nah VW, Hafen; frei, 0160-4433698 o. 0911-7809081.
Gut für Arzt/RA/Ing.büro, oder ruhiges Wohnen, Bilder vorh.



30 Sep 2007 10:32:49
Matthias Voss
Re: No wonder I can't swim

Sheldon wrote:

> "Dan Bracuk" <NOTbracuk@pathcom.com> wrote in message
> news:ki5uf3541r4lak8n3qs5hiip9deeumcnff@4ax.com...
>
>>"Sheldon" <sheldon@XXXXXXXXsopris.net> pounded away at his keyboard
>>resulting in:
>>
>>:I read the difference is two pounds, but that may be splitting hairs. I
>>:have read that some people prefer steel because of the neutral buoyancy
>>as
>>:it empties.
>>
>>I prefer aluminium because it is more positively bouyant. As such,
>>it's less of a weight on the back when diving. Also, if you turn your
>>body, aluminium tanks are less likely to try to flip you over.
>>
>>Dan Bracuk
>
>
> It is a handful, but I had trouble in class with the aluminum tanks.

A crotchstrap would help.

Matthias



30 Sep 2007 10:21:48
Paul Foley
Re: No wonder I can't swim

Sheldon wrote:

> Is there a chart anywhere on the Net that give you theoretical weights for
> dive gear? For example: When wearing a 5 mil wetsuit add X number of lbs.
> Seems to me once you know your buoyancy in a swimsuit in fresh water you
> should be able to get really close when diving in salt water or wearing a
> wetsuit right from the start. Most of the books just say, "You'll need more
> weight when..."

According to Scuba Diving magazine, a new men's wetsuit adds 2 to 3 lbs.
buoyancy per millimeter thickness. Thus a 7mil suit means about 18 lbs.
of lead. These sorts of guidelines are always going to be approximate.
There's more neoprene in a size large suit than there is in a medium.
Probably not all neoprene is created equal. Going from a thin wetsuit
to a thick one also means gloves, booties, and hood get added to the
equation. And then there are those pesky 2/3 suits and 5/7 suits. So
the only way to come up with really meaningful numbers is to create your
own weighting tables. In short, trial and error.


> I was talking to my instructor/shop owner about diving with a 7mil wetsuit
> to get into some of the reservoirs around here. Sounded like I would have
> to hang an anvil around my neck.

With a 7mm suit, hooded vest, and gloves I need 28 pounds. That's about
20lbs. more than I use with a 3/2 suit. An interesting complication to
cold water diving is that you may need a BC with more lift. An
interesting goofball exercise in cold water diving is to go in the water
without any weights at all and learn what it means to float like a beach
ball.


30 Sep 2007 13:24:10
Sheldon
Re: No wonder I can't swim


"Matthias Voss" <spammat.voss@gmx.de > wrote in message
news:fdnn2f$4se$03$2@news.t-online.com...
> Sheldon wrote:
>
>> "Dan Bracuk" <NOTbracuk@pathcom.com> wrote in message
>> news:ki5uf3541r4lak8n3qs5hiip9deeumcnff@4ax.com...
>>
>>>"Sheldon" <sheldon@XXXXXXXXsopris.net> pounded away at his keyboard
>>>resulting in:
>>>
>>>:I read the difference is two pounds, but that may be splitting hairs. I
>>>:have read that some people prefer steel because of the neutral buoyancy
>>>as
>>>:it empties.
>>>
>>>I prefer aluminium because it is more positively bouyant. As such,
>>>it's less of a weight on the back when diving. Also, if you turn your
>>>body, aluminium tanks are less likely to try to flip you over.
>>>
>>>Dan Bracuk
>>
>>
>> It is a handful, but I had trouble in class with the aluminum tanks.
>
> A crotchstrap would help.
>
> Matthias
>
I think I've got it under control, but I'll keep that in mind.




30 Sep 2007 17:33:29
John Mason Jr
Re: No wonder I can't swim

Sheldon wrote:
> "Dan Bracuk" <NOTbracuk@pathcom.com> wrote in message
> news:s5utf3564tsrc9vd11hvlulguicmt86kcr@4ax.com...
>> "Sheldon" <sheldon@XXXXXXXXsopris.net> pounded away at his keyboard
>> resulting in:
>> :But an aluminum tank at 300 psi would be positive buoyant. Correct?
>>
>> Correct, but not necessarly significant.
>>
>> Dan Bracuk
>
> I read the difference is two pounds, but that may be splitting hairs. I
> have read that some people prefer steel because of the neutral buoyancy as
> it empties.
>
>

You need to make sure your configuration allows you to have some
ditchable weight. Otherwise make sure you can swim up your rigfrom depth
in case of a wing failure.


John


30 Sep 2007 17:36:14
Sheldon
Re: No wonder I can't swim


"John Mason Jr" <notvalid@cox.net.invalid > wrote in message
news:13g05h8634vvlfe@news.supernews.com...
> Sheldon wrote:
>> "Dan Bracuk" <NOTbracuk@pathcom.com> wrote in message
>> news:s5utf3564tsrc9vd11hvlulguicmt86kcr@4ax.com...
>>> "Sheldon" <sheldon@XXXXXXXXsopris.net> pounded away at his keyboard
>>> resulting in:
>>> :But an aluminum tank at 300 psi would be positive buoyant. Correct?
>>>
>>> Correct, but not necessarly significant.
>>>
>>> Dan Bracuk
>>
>> I read the difference is two pounds, but that may be splitting hairs. I
>> have read that some people prefer steel because of the neutral buoyancy
>> as
>> it empties.
>>
>>
>
> You need to make sure your configuration allows you to have some
> ditchable weight. Otherwise make sure you can swim up your rigfrom depth
> in case of a wing failure.
>
>
> John

I hear ya. All of my OW testing was done with an empty bc, even down to
60', and my goal, when practicing in the pool, is to use as little air in
the bc as possible. I assume the object is to use just enough weight to get
down and as things compress you'll pick up speed. I can ditch all my
weight, but I want to make sure that when I ascend I don't pop to the
surface like a cork. Eventually some "real" diving will help me dial in
what I need, and someone else had a great idea of splitting your weight. My
bc has nice pockets so splitting my weight will be easy.




30 Sep 2007 20:15:51
Dan Bracuk
Re: No wonder I can't swim

"Sheldon" <sheldon@XXXXXXXXsopris.net > pounded away at his keyboard
resulting in:

: I assume the object is to use just enough weight to get
:down and as things compress you'll pick up speed.

No, the object is to use just enough weight to keep yourself
underwater at the end of the dive. If you achieve that, the beginning
will take care of itself.


Dan Bracuk
Never use a big word when a diminutive one will do.

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.comThe #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----


30 Sep 2007 22:30:30
Tazz
Re: No wonder I can't swim

<snip >
> With a 7mm suit, hooded vest, and gloves I need 28 pounds. That's about
> 20lbs. more than I use with a 3/2 suit. An interesting complication to
> cold water diving is that you may need a BC with more lift.

When my gear was new, 6 mil DRYsuit 5 mil gloves and hood, I needed 36
pounds. Now, about 35 dives later, I only need 32 pounds.


> An interesting goofball exercise in cold water diving is to go in the water
> without any weights at all and learn what it means to float like a beach
> ball.

I did this by mistake on my third or fourth dive. I jumped in and let
all the air out of my BC and suit. Didn't sink. Was floating quite high
actually. Then I tried the "head down-bend at the waist-then legs
straight up" thing. My fins didn't even go under. Then I checked my
weight belt to see what was wrong with it. Hmmm, I guess I forgot to put
it on. Climb up the ladder, across two boats, put belt on and jump again.


--
</TAZZ >


01 Oct 2007 15:48:19
Sheldon
Re: No wonder I can't swim


"Dan Bracuk" <NOTbracuk@pathcom.com > wrote in message
news:qfi0g3he79dg3p89tql134fonntcqsib1c@4ax.com...
> "Sheldon" <sheldon@XXXXXXXXsopris.net> pounded away at his keyboard
> resulting in:
>
> : I assume the object is to use just enough weight to get
> :down and as things compress you'll pick up speed.
>
> No, the object is to use just enough weight to keep yourself
> underwater at the end of the dive. If you achieve that, the beginning
> will take care of itself.
>
>
> Dan Bracuk
> Never use a big word when a diminutive one will do.

I should have said "stay down." I'm aware that when you check buoyancy you
have to do it with an almost empty tank, or a full tank and then add weight
to compensate for the difference at the end of the dive.