Some divers need bigger tanks; Some need thicker suits...?

[DandyDon]

We've talked around this some, but I don't think I've ever seen my understanding of an idea in mind actually confirmed. Let me present it here.

Some divers go thru air faster than others, while some use less - in particular women seem to use less, as do more experienced, relaxed, skiled divers.

And some seem to get chilled more easiy than others - in particular women, as well as more experienced, relaxed, skiled divers.

Somewhere along the way, chatting with other divers, these two generalities come together in an obvious connection to me, and I've mentioned it, but no one has ever commented either way. Here's my understanding for comments, please:

Newbies go thru air faster, for various reasons, and with that - burn more calories, therefore chill less;

With the exception of women, even though they generally do not have a lower adipose ratio, chill faster - because they use less air and burn less calories;

And the more experienced, as they learn to burn less air, chill faster, as they burn less calories as they use less air.

This all seems obvious to me. Of the divers with 100 or more logged dives, do you remember having to go to thicker suits for the same conditions after you gained experience...?

 

[Drew Sailbum]

Thicker suit? Nah. Diving in warmer water works just as well

Actually most of my early diving was in really cold water in completely inadequate thermal protection. The dives were very short to shallow depths while assembling piers only days after the ice cleared the Wisconsin lakes.

Air consumption rate wasn't really an issue. I wouldn't have had a clue how long an Al80 would have lasted at those depths at that time since I was never in the water long enough for those dives to use an entire fill.

Fast forward several years, and I'm not so sure that it is experience or thinning blood that makes me and my fellow Caribbean dive instructors wear thicker wetsuits than the guests. I lean toward the latter. When I first arrived, I never wore a wetsuit. Now I usually do and I've been browsing the thicker full length wetsuits for those winter months. Can't imagine that I've changed my SAC rate much at all in that time.

 

[fdog]

Actually, at the time, I was a starving college student teaching diving...instead of getting a thicker suit, for a while I just dragged the students out earlier when I got cold...

At the same time, I switched to wearing 50's, because I was tired of lugging around the weight, and coming out with 2/3s of a tank.

I still use 50s and 63s alot and I'm definitely a cold weanie.

All the best, James

 

[theskull]

One obvious answer is that as your SAC rate improves you can remain at depth longer, where the water carries away more of your body heat. This effect multiplies the more repetitive dives you do over a number of days. Therefore you learn to wear more exposure protection.

theskull

 

[Snowbear]

One obvious answer is that as your SAC rate improves you can remain at depth longer, where the water carries away more of your body heat. This effect multiplies the more repetitive dives you do over a number of days. Therefore you learn to wear more exposure protection.

Ain't THAT the truth! Learning to slow down, stop and look at the little stuff burns less calories as well. It can get dang right chilly after 70 minutes in 48F water, even in a drysuit

 

[jagfish]

And some seem to get chilled more easiy than others - in particular women, as well as more experienced, relaxed, skiled divers....With the exception of women, even though they generally do not have a lower adipose ratio, chill faster - because they use less air and burn less calories...

One factor that can be a significant issue for women (especially here in asia) when is comes to retaining heat, is that of body mass.

An interesting geometric fact in the animal world has to do with the relationship between surface area and volume. In the formulas for each of those values, as "r" (the radius of the object in question, in this case human beings) increases, the surface are increases by "r squared" while volume increases by "r cubed", the latter at a much greater rate.

So, big things gerally hold more heat, because they have a lower surface area to volume ratio, which is why overweight people sweat a lot. Conversely, small people have a lot of surface area for thier volume and give off heat much more quickly to water or air.

JAG

 

[eod]

I hope that I don't have to get a thicker exposure protection, a drysuit with a 300 undergarment is hard to beat.

But I DO hope that my air rate will go down.

 

[sharkmasterbc]

From my understanding your body will "aclimatize" to the temp you are diving in therefore after a while you will keep more blood in your core and less in the extremities. This could definetly produce a lower sac as your body is requiring less 02 to function. Your body "rememberes" that the last time your hands got cold which required more blood to warm, after some time it realizes that it is much more effective to "pool" the blood in the vital parts to save its energy. In the carrib I started w/o thermal protection but by the end of 9 months I was comfortable n a 5-4mil, also up here in the PNW I definetly get cold easier now than I did one year ago. It seems that argon may be the only answer.

By the way whats the law about distance from a diver down flag a vessle must stay. Only wondering cause it seems to be diff in every place I go.

 

[Kim]

In Malaysia with water temps around 29C all the visiting customers (including my wife who even dived a T-shirt on one day) were fine diving 3mm shorties. All the instructors and DM's wore full wetsuits (also 3mm). A couple of them told me that actually they were often cold - and were considering getting 5mm suits.

 

[Jeddah Aquanaut]

One obvious answer is that as your SAC rate improves you can remain at depth longer, where the water carries away more of your body heat. This effect multiplies the more repetitive dives you do over a number of days. Therefore you learn to wear more exposure protection.

theskull

Sometimes more exposure protection can be as simple as a hood, and not a thicker wetsuit. Here in Jeddah, the temp's about 29C now. A hood without a bib works just fine to keep in a goodly amount of body heat. Gloves too. It's just like winter back in Vermont. You lose so much body heat through your head and hands, if not covered.