Question about depth / decompression?

[ameri180304]

Noob question, but I have my SDI scuba... When I went through that training, was told to come up / go down slowly. Long story short, I bought free diving fins, and wanted to swim down 20-30feet several times for photography (just by holding my breath).

I assume, since I'm not breathing and but rather holding my breath, I'm fine?

I guess what I'm asking is if I want to go snorkeling, and swim down 20-30 feet, then quickly come up (in one breath), am I good?

 

[Edward3c]

Decompression isn’t a consideration when snorkelling or freediving. However, if you’ve been diving early in the day there could be an issue because of micro bubbles.

 

[boulderjohn]

You can go down and up as fast as you want to.

 

[boulderjohn]

This may help:

No-limits apnea - Wikipedia

 

[rx7diver]

However, if you’ve been diving early in the day there could be an issue...

+1

 

[fisheater]

Unless you freedive deep and frequently, you don't have to worry about decompression. (Yes, extreme freedivers do have DCS considerations.)

However, you DO have dangers, such as blackouts, to worry about. I STRONGLY suggest you take a freediving safety class, where you'll learn the dangers and how to avoid them (mainly through proper buddy procedures, one up and one down and knowing how to revive a blacked out diver).

 

[dcvf2]

Hi,
In June 2007, Herbert Nitsch during his record at -214m. Unfortunately, I can no longer find the dive profile (depth / time)

 

[Vicko]

In your case you are fine, it's hard but not impossible to get DCS from freediving.
There are many competitive free divers and spearfisherman who have gotten DCS from freediving, usually because going very deep (no limits deep 150m+) or doing many dives in a short amount of time (like a dive a minute to 15-20 meters for hours).

 

[Subcooled]

[removed/duplicate]

 

[Subcooled]

Noob question, but I have my SDI scuba... When I went through that training, was told to come up / go down slowly. Long story short, I bought free diving fins, and wanted to swim down 20-30feet several times for photography (just by holding my breath).

I assume, since I'm not breathing and but rather holding my breath, I'm fine?

I guess what I'm asking is if I want to go snorkeling, and swim down 20-30 feet, then quickly come up (in one breath), am I good?

Going down slowly while SCUBA-diving because:
1) you will need some time to equalize your ears (you can cut the time by gaining experience)
2) you will need to exhale to get rid of excessive CO2... and a ridiculously fast descent would require continuous inhaling instead
3) compression stops only matter in some Extremely deep dives not relevant here. I am not the correct person to cover this matter in detail.

Going up slowly because
4) you must allow the compressed air to exit your body in a controlled fashion

- In freediving 1) is something you solve by repetitive training
- In freediving 2) does not happen because of short duration
- In freediving 3) does not happen [saying nothing about 'No limits' here]
- In freediving, there is no compressed air and hence 4) becomes a non-issue (unless you dive to 600ft)(I'm not a competition freediver so numbers are approximate)

Please do read about ascent blackout. O2 partial pressure is greater at depth (hence maintains consciousness) but once you ascend, the O2 pp will drop, and so will you consciousness. People have lost their consciousness on the way up, and died.

If you die, it is not my fault.