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Ron
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Vintage Tank Bouyancy Characteristics

Fri Sep 19, 2014 1:34 pm

10707947_1485002395099463_1871319486_n.jpg
Copied from the 2nd edition of Basic Scuba, by Fred Roberts.

NOTES:

-a 42 is a 38 filled to 2068 PSI
-both the 2015 PSI "70" and the 2250 PSI "72" are encompassed in the 70 on here.
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Herman
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Re: Vintage Tank Bouyancy Characteristics

Fri Sep 19, 2014 5:50 pm

Hummmm, that does not jive with the measured amounts of my steel 38s. They are around 2 lbs neg full (1800) and 2 positive empty. That includes the manifold and 2in1 backpack. Almost a prefect amount for me.
Herman

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antique diver
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Re: Vintage Tank Bouyancy Characteristics

Fri Sep 19, 2014 10:17 pm

Herman wrote:Hummmm, that does not jive with the measured amounts of my steel 38s. They are around 2 lbs neg full (1800) and 2 positive empty. That includes the manifold and 2in1 backpack. Almost a prefect amount for me.
Just from my experience there is a lot of manufacturing variation in what is assumed to be the "same tank", especially over a period of time. I have 38/40/42 types that are all over the place on buoyancy characteristics. :? I would have to say the book might be a little outdated on that subject at this point... (but still a dang fine book overall).
The older I get the better I was.

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Ron
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Re: Vintage Tank Bouyancy Characteristics

Fri Sep 19, 2014 11:38 pm

There's a pretty wide variance. I think Mr. Roberts was just giving us a SWAG at it. I have a "standard 70" 2150 PSI tank that is -2 lbs full and +1 lb empty. I also have two 72's that are about -4 lbs full and neutral empty. I posted this because apparently this book is getting very hard to find, and several divers have sent my PM's looking for this page in particular. It's a nice starting point anyway 8)
The impossible missions are the only ones which succeed. -JYC

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antique diver
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Re: Vintage Tank Bouyancy Characteristics

Fri Sep 19, 2014 11:59 pm

I love the book.
The older I get the better I was.

Automan
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Re: Vintage Tank Bouyancy Characteristics

Tue Dec 09, 2014 1:44 pm

I tend to just use this calculator for new and old tanks

http://www.subaqua.co.uk/cylinder-buoya ... s=imperial

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luis
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Re: Vintage Tank Bouyancy Characteristics

Tue Dec 09, 2014 9:08 pm

Automan wrote:I tend to just use this calculator for new and old tanks

http://www.subaqua.co.uk/cylinder-buoya ... s=imperial

Thanks for the link.
I like that calculator.
Luis

Buceador con escafandra autónoma clásica.

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