The Amazing Air Sucking Vacuum

[Jamdiver]

Body composition and race make a difference in your personal "naked" buoyancy. Asians have lighter bone structure, and tend to float quite easily. Caucasians are in the middle, and people of African descent have the heaviest skeletons. Watch olympic swimming some time, and then watch olympic runners, and then watch gymnastics. Race makes a difference. Fat also floats better than muscle. I have osteopenia, the precursor to osteopenia, or basically just genetically light birdlike bones. My frame makes me float. Luckily, I don't have much body fat, or I'd never get down. Just because someone else is the same height and weight doesn't automatically mean they have the same amount of muscle, fat, and bone density as you.

Hey Shadow,

I'm going to have to call you out for this somewhat.
Coming from a scientific background, i'm loathe to hear people make such generalizations without backing scientific data, i.e. studies.
Heavier skeletons implies greater bone density.... :06:.
Skeptical of your supposition to say the least.
IMO the individual variability in body composition, i.e., percentage of muscle and fat in a person's body composition is going to vary a lot more from person to person than throughout a 'race'.

Persons come in all shapes and sizes regardless of race.
Was this information given to you by your doctor?

Regards .

 

[SwimJim]

Come to Chicago and jump into a quarry with me...see how you like 50 degree water. You have a good point though...

I love 50 degree water. I dove a local lake on Sunday and the thermometer on the depth guage was pegged on the bottom. My computer was reading 37. Its starting to get chilly around here. Come on up to Fish Creek in Door county Wisconsin Sunday Dec 4. There is a shore dive at the marina. Last one in..... well you know the rest. Ha

jim

 

[Talon]

You seem to indicate that your air consumption is MUCH higher then normal. Sorry, but I don't believe being even 6-8# overweight is going to create THAT much of an issue.

The MUCH more likely culprit is the change in environment. My guess would be either nerves or excitement (probably both). Either that or you were more active underwater then normal (i.e., swimming all over the place in a hurry). Those things will have a HUGE impact on your air consumption - not a little extra lead.

There are several techniques to improving your air consumption. Do a search on this site and you will find a wealth of information. But the one constant will be - DIVE MORE

 

[Fish_Whisperer]

Dive more... Living in Tennessee, I don't often get the chance to dive, but I can usually go over to the Rec Center pool, which is 12' deep, and swim around in there, if no one's using the pool for some sort of event. Will this help, even though I'm not at any great depth?


One thing that my instructor told me, was that humming while you breathe, will help. He said he hums, "I Wish I Were An Oscar Meyer Weiner." LOL

Personally, I hum the brass solo from "You're Just Too Good To Be True."

*ahem*

"da-NA da-NA da-na-NA-NA!! da-na NA na NA na na NA NA!!" er... Like that.

Okay.. That's enough. I've officially embarrassed myself enough.

/crawls off to hide under the couch....

 

[TheRedHead]

I could see how humming would be helpful with longer exhales.

 

[pasley]

Many divers who travel to dive elect to just rent their gear there or to just bring their own regulator and computers due to convenience and is not necessarily an indicator of inexperience or that they do not dive often.

I'm starting to think that I may have been overweighted...especially since I keep getting the same responses. I had no trouble getting neutral with just a little bit of air...

How much air is a little bit?

but did fin quite a bit.

An indicator of too heavy and it uses up your air.

My assumption was that the salt water would negate the loss of neoprene (shorty vs. full length, hooded vest).

I believe you assumption was faulty. Salt water adds buoyancy so more weight is required in salt Vs fresh water. Less neoprene (no hood, vest or full 7mm suit) means less weight is required. So far so good. So the issue is does added buoyancy of the salt water equal the change of buoyancy of the lost neoprene? It appears the answer is no. You will have to figure it out for yourself as we do not have all the information (weight of wetsuit used at home Vs weight of wetsuit used on vacation, but the relevant facts are:

In general : Fresh water has a density of 1.0 while salt water has a density of 1.025. When going from fresh water to salt water, multiply the fresh water weight by .025 and add that to the fresh water weight.
You don't say what weight of wet suit you dive at home, just that you were not wearing a full wetsuit.

Assuming (theres that word again) you dive a 7mm full suit at home we have quite a weight shift.

The change in wetsuit: Neoprene is 2 to 3 pounds buoyant for every pound it weighs in air, depending on the quality of neoprene and age of the suit. (1mm neoprene skins, being proportionally more nylon, are less buoyant.)

So if I had a 7mm wetsuit at home that weighs 6 pounds that would need 18 pounds of lead. A 3mm wet suit that weighed 3 pounds would require 6 pounds of lead. A subtraction from my weight belt of 12 pounds!

In addition to being overweighted add excitment, after all itis Jamacia man! Bottome line, check the weight issue and then don't sweat it.

 

[miketsp]

Hey Shadow,

I'm going to have to call you out for this somewhat.
Coming from a scientific background, i'm loathe to hear people make such generalizations without backing scientific data, i.e. studies.
Heavier skeletons implies greater bone density.... :06:.
Skeptical of your supposition to say the least.
IMO the individual variability in body composition, i.e., percentage of muscle and fat in a person's body composition is going to vary a lot more from person to person than throughout a 'race'.

Persons come in all shapes and sizes regardless of race.
Was this information given to you by your doctor?

Regards .

Have a look at this and some of the referenced articles.
http://jcem.endojournals.org/cgi/content/full/87/7/3047

 

[Jamdiver]

I stand corrected Mike,
however I think blanket statements like the poster made are somewhat misleading.
They're so many other factors affecting BMD,lifestyle factors (diet), health, individual body types et cetera.

Anyway thanks for the link i'll bookmark it for more detailed reading later.

 

[lamont]

Learning to swim freestyle/crawl is good for learning breath control. The more strokes you can take without taking a breath the more efficient you are, and in the process you learn how to control your breathing while excersizing, which is very applicable to reducing SAC rates while scuba diving.

I was a really horrible swimmer, but i've spent a few months going to the pool and I hit a record low SAC rate for me of 0.45 cuft/min a week ago on a dive.

 

[ItsBruce]

On further reflection, I think a part of the air usage equation is excitement or nervousness over diving a new location like you did.

On a test, my yoga teacher, who has never dived, did a SAC of 0.43. (Guess why I'm taking yoga?)