neutral without suit/weights?

[immerlustig]

recently i let myself being talked into some 'extreme snorkeling' , that's local lingo for no fins/no suit in cold water (not to be confused with 'unashamed', though!).
however, i had a go and to my surprise i was still mildly positive at 19m. i wouldn't have expected that. in saltwater, no packing, no weights. (i didn't try again because of acute fost)

anything comparable anyone?

roland

 

[JasonWelbourne]

19 meters? You sure you don't mean 19 feet? To be positive at 19m with no bouyancy adjustments sounds completely insane to me..
I personally am negative at 19 meters with a 3/2 wet suit and no weight.
Without a wet suit I hit neutral boyancy right around 10 meters.

 

[Pezman]

Roland,

Individual buoyancy is a funny thing and depends on a lot of different factors, but -19m doesn't seem hugely surprising in salt water and w/o fins.

Fins are usually negative ballast. In fresh water, if I pack, I'm slightly positive. With WW #4 fins, packed to the max in fresh water, I sink like a rock.

You need to add nominally 3% of your body weight in ballast when you go from fresh water to salt. However, this varies w/ the salinity of the water, which I think varies with locale, season etc. A high salt level will add buoyancy.

Just to do a little comparison, in salt water with WW #4s and no wetsuit, I'm neutrally boyant at -10m. In fresh water with fins, I'm negtive at the surface. That means that I undergo a shift in neutral buoyancy level of more than 10m just by going from fresh to salt water -- and that's in the first 10 meters, where the change in buoyancy due to compression of the chest cavity is the greatest. Add in the effect of the fins and you get a few more meters so I would expect that my neutral buoyancy level in salt water w/o fins would probably be at least -15m.

Just to round the example out a little, if Jason's figure of "neutral at -10m" is for fresh water diving, then he'd probably be slightly positive at -19m in salt water.

 

[Erik]

Don't forget that Roland is diving in the Red Sea. It's much more saline than most oceans. I needed more weight than expected when I was there.
Cheers,
Erik Y.

 

[efattah]

Diving with no suit, no weight, even in fresh water, I am still positive at 12m-15m, at least, with full packing.


Eric Fattah
BC, Canada

 

[DeepThought]

Sounds very sensible to me Roland. I was slightly positive in Thailand at about 15m with fins and no suit. I barely ever had the chance to feel negatively bouyant there (exculding exhaling while breathing at the surface).

Red-sea is defenitly more saline than the andaman or the gulf of Thailand. And you probably have a better lungs to body mass ratio than I had as a newbie.

You should keep practicing that 'extreme snorkeling', if you'll be good enough, you might score a job as a snorkeling guide.

By the way, what's "acute fost"?

 

[LiquidRush]

frost maybe? poor roland

 

[waterlover]

i'm very familiar with no fins, no snorkel, no suit diving. either you have a very high ratio of body fat or you made a small mistake concerning the depth (probably 4 or 5m less).

 

[rubberpag]

i don't think he's mistaken. i also tried extreme snorkeling in the very same sea, and i'm still positive buoyant at 15. i tried with one kilo, and i'm neutral at 13/14. and my body fat is not much really. and immerlustig is definitely on the skinny side!

cheers.

 

[immerlustig]

waterlover: you saying i'm fat??--careful, dude:blackeye

liquidrush: frost indeed, 25 celsius! the horror, the horror

since i'm indeed on the skinny side, a possible reason might be that i don't have heavy thoughts.

however...

pezman: no weights? a 10m difference seems mighty much to me. my positive buoyancy at 19 is really light, i'm just ascending barely making sure i don't move anything at all.

maybe i try again sometime.

cheers

roland

 

[Pezman]

Hey, at least I didn't speculate that you were fat.

There are some older posts around here about the dramatic difference that a pound or two in weight can make in the level at which neutral buoyance is acheived. Note that the deeper that you go neutral, the more gradual the transition is. You might find the you're just barely positive at 10m as well.

If you unravel the mystery, let us know. It's pretty clear that precise knowledge about this topic is in short supply around here.

 

[kingohyes]

Originally posted by immerlustig

liquidrush: frost indeed, 25 celsius! the horror, the horror

cheers

roland

25¨celcius!!! We didnt even got 25 celcius in the summer.. I go diving without suit or anything if its anywhere near 20.. I have dived in 12 degrees celcius with 8 degrees on the bottom..

 

[waterlover]

sorry buddy, immerlustig, i didn't mean to say you're fat.

I just said there was a possiblility your fat ratio is a tad on the up side.

You'll have to agree that in most seas, oceans, lakes and rivers being at -19m with a swimsuit plus no fins means negative buoyancy. (notable exception... maybe the Dead Sea).

But to be honest, when i've been at -19m in frigid water in a swimsuit, my head feels like it is about to explode and like somebody's hit my chest with a sledgehammer and i'm shivering and moving so much (to keep warm) that i don't know what the heck bouyancy i have! That's the truth.

I guess the most important thing to note in all these threads is:

these kinds of dives are VERY DANGEROUS in cold water.

 

[DeepThought]

It's not fat, he just has big lungs.

And I'de say it's a definitly for the Dead sea. I think you float there even with empty lungs. But you'de have to be pretty brave (or stupid) to go 19m down there. Though can't say I never thought about it.