Weight for dynamics

You don’t want to be totally neutral but very slightly positive. Once you start your breath hold, you burn O2 and produce CO2. CO2 is denser so at the end of your dynamic you’ll be LESS buoyant. So if you start a little positive, you will be about neutral at the end.

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I'm pretty new to freediving, and I don't mean to be rude, but this doesn't make any sense whatsoever. It is true that at the same pressure, volume for volume, CO2 weighs more than O2, but:

a) A human body holding it's breath doesn't magically gain mass. The extra mass would have to come from somewhere. In this case the extra carbon atoms are a waste product of your metabolic processes, so they are only in your lungs because they aren't somewhere else in your body.

b) Say you have a lung capacity of 6 litres and 21% of that is O2 at the start of your dynamic. Even if you replaced allthe O2 in your lungs with CO2 (which I suspect is incompatible with being conscious/alive), you'd only have 1.26 litres of CO2 at the end of your dynamic. The difference in mass between 1.26L of O2 and 1.26L of CO2 is utterly negligible in this context.

If you're losing bouyancy during a dynamic it will be for some other reason.

Cheers,

Niall

Dear Niall,

It's true, the body doesn't gain mass. But it loses volume.

It's true, the body doesn't gain mass. But it loses volume.
__________________
Panos Lianos
Athens, Greece

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My apologies, Panos - I misunderstood the point you were making

When it comes to the relative volumes of inhaled and exhaled gas, I have to admit to a degree of ignorance. Can you point me towards some literature on the topic?

Cheers,

Niall

So thats why i start off dynamics well weighted and at the end my knees are scraping the bottom. rofl

Last night I took my pregnant wife to a pool so she could have some gentle exercise and I could do some diving. The pool has 25-meter lanes going lengthwise to a bulkhead and 25-yard lanes going crosswise on the other side of the bulkhead. Two swim teams have the pool before its public swim. One swim team kept practicing through the public swim and used every 25-meter lane.

I usually have my wife spot me by means of holding onto a dowel connected to spectra line connected to my wrist. I have to be in a side lane and she walks along the side of the pool as I swim. Well the only side lanes are in the 25-meter section, which meant there was no means for her to spot me. In trials before she was pregnant she couldn’t consistently pull me up from the bottom when she swam on top, plus she couldn’t keep up with me either.

Since the situation was less than ideal I decided to dive conservatively and experiment with different weighing. No spotter for me, means I stop at 50 yards or meters. I have two necks weights, which I have made from attaching two ankle/wrist weights together. One is made up of 1-pound weights and the other 2-pounds. So through combinations I can go from 2lbs to 6lbs. I was wearing a 1.5mm suit.

I glided by pushing off the wall several times and did four 50-yard dives with various combinations. Then I put the 1lb weights on my ankles. I tried various combinations and ended up with 4lbs on the neck, 3lbs on the waist, and 1lb each on the ankles. In a glide I would glide almost to a complete stop before slowly ascending (I was in 6’ of water). But when ascending, just before the surface, my feet would sink and I would come vertical. This didn’t seem ideal, but then again this was after coming to almost a compete stop, which isn’t going to happen during the dynamic anyway.

From just a push of the wall, I could glide further than with any other weight combination I tried that evening. I realized I probably didn’t need to fin as hard and fast as I had been. In the dynamic I really had to raise the arms high to keep off the bottom of the pool, but after about the first 20-yards I got the right water column height and was able to maintain it. At 50-yards I felt better than I had on any previous attempt so I decided go for 75. At 75 I still felt good, but knew I shouldn’t push it without a spotter so I did the turn kicked twice and came up.

Simo K, might be right! Maybe some people do need some weight on their ankles if they are wearing a suit, which causes their legs to be buoyant. I am eager to experiment more with this when I have a spotter and can push myself closer to the limit. I would also like to get a neck weight like Aaron has where I can try a larger range of weights. Does anybody know where I can buy one over the internet? Aaron, how about and e-mail address or phone number to your local shop?

I’m also going to get Pelizzari's "Manual of FreeDiving" per Connor’s suggestion and try to learn what he teaches about proper fining.
don

Cool, I'll have to try that my self. I was thinking that after you find the right weight, you could mold some lead into a more hydrodynamic shape and just glue it on the fin someplace.

Don,
I'll pm you with the phone # and email address.

BTW, my copy of "Manual of Freediving" just arrived... It's looking like a grand read

Aaron

I have a question, does the neckweight bump you in the chin and hurt alot? Can a neckweight be made for a gal (my size-5'3", 105 lbs)???

Reading this thread brought up some concerns I also have when swimming with my 7mm and monofin in the lakes. I want to be buoyant enough to surface, yet, with just the weightbelt, my torso doesn't stay aligned well to swim. I never considered a neck weight because I hate anything around my neck (just feels panicky), but I saw in Peter Pedersons mono dynamic that it looked very effective.

thanks for the pics too

No, I don’t think so. I have even seen ones like Aaron’s, but with uncoated lead weights and people didn’t seem to have a problem even without a suit. Ones made out of lead shot in bicycle inter tubes or two ankle/wrist weights clipped together, are soft.

I assume now that they are legal in CB competition, they are going to become the norm. For me once I tried it, I never want to dive without it again. Aaron is helping get one like his from Canada!
don

kingohyes said:

I believe there has been an thread on this board earlier about how to make a neck weight. Im very interested in making one. I dont want to use a bicycle lock.

Please describe how to make one.. I really need it.

When im fully packed, I float up from 4m really fast.. I even float up when holding a rescue doll. :wave

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Some days ago I bought an ankle weight (0.5 kg) ! And it fits perfectly to my neck !!

I trained today with following weights :

a belt with 1 kg + 0.5 kg ankle weight at the neck

I did DNF... but I felt I need to add weights.... I am buying a second ankle weight (0.5 kg)... I can also add to my ankle weight a normal 0.5 kg...

Then I can load my neck with 2 kg... I am doing it progressively in order to be perfectly balanced...

This morning I did 7-8 strokes per 25 m... probably because I am not enough weighted : when I feel I am going upwards, it prevents me from relaxing and gliding... and it renders me quite hectic...

Kars put a 2.5 kg weight at his neck and Stig Severinsen added 3 kg at the neck too... without wet suit of course...