Speed and gas consumption

[marchand]

What you will see is that y increases exponentially with x. In other words, you can cover the most distance for the least amount of gas if you kick rather slowly. This is because, in water, drag (and thus gas consumption) quadruples with the doubling of the speed.

You need to convince yourself that when you're low on air, the best way to maximize your chance of survival is to proceed at a leisurely pace, not a rushed pace, to optimize gas consumption.

I beg to disagree. while it is true that drag increases exponentially with speed the same is not necessarily true for gas consumption (on open circuit anyways). back in my swimming days I could swim anywhere from 0 - 75'/min with no increase in my breathing rate. Why? because at the slower speeds you are being very inefficient. its kind of like driving; 2000 rpm in 5th gear is a heck of a lot more efficient than 2000 rpm in 1st gear. In other words, you can cover the most distance for the least amount of gas when you swim as fast as you can without affecting your rate of breathing.

 

[Doc Harry]

I beg to disagree. while it is true that drag increases exponentially with speed the same is not necessarily true for gas consumption (on open circuit anyways). back in my swimming days I could swim anywhere from 0 - 75'/min with no increase in my breathing rate. Why? because at the slower speeds you are being very inefficient. its kind of like driving; 2000 rpm in 5th gear is a heck of a lot more efficient than 2000 rpm in 1st gear. In other words, you can cover the most distance for the least amount of gas when you swim as fast as you can without affecting your rate of breathing.

That's a really excellent point. And it might be true for some people, depending on your swim speeds. That's why I think you've got to go out there and do the test yourself. What I consider a leisurely pace may not be what you consider a leisurely pace.

My personal experiment does not support you assertion for me.

During my first swimming trial, I kicked at a really leisurely pace, much slower than I would ever swim. Almost too slow. The numbers showed that this pace gave me the lowest gas consumption per distance than any other speed (i.e., the highest miles per gallon).

My second swimming trial was at my "normal" speed. My gas consumption was 50% higher per distance (i.e, MPG was 50% lower). I didn't perceive any subjective increase in respiratory rate.

My third and fourth swimming trials were faster, and that's when I did notice an increase in my respiratory rate. My gas consumption rate per distance was twice that of the first trial.

So I know my numbers, but someone else may have different numbers based on their speeds. That's why I'm interested to see other people's data.

Marchand, you and I both know our most efficient pace, and that's what's important. Everyone else has to learn theirs.

Thanks.

 

[marchand]

I was just concerned that people would just read your post and assume that the slower they go the more efficient they are going to be with their gas supply and not do any testing at all, and then one day when the SHTF decide to try it out.