ADVERTISEMENT

Author Topic: In lost buddy drill, should one do safety stop while ascending to the surfacing?  (Read 4510 times)

Fireflies

  • Member
  • ***
  • Posts: 147
  • Liked: 20
  • Karma: +3/-0
  • Singapore Scuba Diving Forum
Just wondering, do free divers do safety stops? Done of them Dive really really deep and with just one very deep breath, they can't do safety stops right
noob.

runez

  • Member
  • ***
  • Posts: 208
  • Liked: 44
  • Karma: +6/-1


If I exceed the rdp suggested Dive time I will do a safety stop. If it's recommended for 60 mins Dive time at 10m and I'm less than 10 minutes away from 60 minutes I would do safety stop. Unless my friend is in trouble, any kind of trouble, I would skip it completely and help my friend.

If you exceed the PADI RDP, it's no longer a safety stop. That would now be a mandatory deco stop.

The good news is, the RDP states a NDL of 205 minutes at 10m. Unless you have the lungs of a fish, almost nobody will hit 205 minutes on a single tank.

Because you mentioned 10m specifically, interesting tidbit about diving physiology: During early decompression studies by Haldane, he observed that humans could surface directly from an indefinitely long dive at 10m without any DCS symptoms. This was the basis for Haldanian decompression models. Decompression theory gas come quite a long way since, but most will still allow an insane amount of dive time, that recreational divers are very unlikely to hit, at 10m before incurring decompression obligations.

Sent from my HTC One using Tapatalk

The Golden rule of diving - Any diver can call the dive. At any time. For any reason

BareBear

  • Member
  • ***
  • Posts: 623
  • Liked: 39
  • Karma: +18/-6
  • Singapore Scuba Diving Forum
Just wondering, do free divers do safety stops? Done of them Dive really really deep and with just one very deep breath, they can't do safety stops right

The air in their lungs is at atmospheric pressure. They are not breathing pressurized gas.

runez

  • Member
  • ***
  • Posts: 208
  • Liked: 44
  • Karma: +6/-1
The air in their lungs is at atmospheric pressure. They are not breathing pressurized gas.
But at depth, the lungs will be compressed and consequently, the tissue compartments will on-gas accordingly. There have been reported cases of free divers getting bent, typically over multiple aggressive free dive profiles.

Some additional reading here: http://www.skin-diver.com/departments/scubamed/FreedivingCauseDCS.asp?theID=626

Sent from my HTC One using Tapatalk

« Last Edit: 21 Nov 14, 16:32 by runez »
The Golden rule of diving - Any diver can call the dive. At any time. For any reason

Ddivex

  • Member
  • ***
  • Posts: 290
  • Liked: 13
  • Karma: +4/-5
but they dont do safety stop.
how to do? ;D
revolution is nothing but the start of the next fall.

Fireflies

  • Member
  • ***
  • Posts: 147
  • Liked: 20
  • Karma: +3/-0
  • Singapore Scuba Diving Forum
Runez: I like that you found real studies of the 10m theory! Awesome
noob.

BareBear

  • Member
  • ***
  • Posts: 623
  • Liked: 39
  • Karma: +18/-6
  • Singapore Scuba Diving Forum
But at depth, the lungs will be compressed and consequently, the tissue compartments will on-gas accordingly. There have been reported cases of free divers getting bent, typically over multiple aggressive free dive profiles.

Some additional reading here: http://www.skin-diver.com/departments/scubamed/FreedivingCauseDCS.asp?theID=626

Sent from my HTC One using Tapatalk

Wow, very interesting!

Cool79

  • Member
  • ***
  • Posts: 202
  • Liked: 6
  • Karma: +5/-14
  • Singapore Scuba Diving Forum
Unless u r in deco, then u need to do deco stop. If not there is a risk of gana bend.

gnulab

  • Newbie
  • *
  • Posts: 3
  • Liked: 0
  • Karma: +0/-0
  • Singapore Scuba Diving Forum
To answer OP question, before veering off to the topic of Situational Awareness, I'd say you need to prioritize your needs.
You're in deco, but there's a mean looking shark circling you. Do you still do deco stop?

1st Q is, if you're still within NDL.
  • Assess situation, enough gas? situation clear of imminent danger? anyone in need of immediate medical attention?
  • Deploy SMB
  • Do safety stop

2nd Q is, if you're deco.
  • Assess situation
  • Deploy SMB
  • Orient yourself
  • Check available gas
  • Check current depth
  • Check Ceiling time, light deco, just use 1/2 max depth, +1 min at every 3 meters stop
  • At 30m, you'll need at least 7 minutes to reach to the surface
  • You'll need 50 bar of air to reach the surface (to be on the safe side).

HTH
Henry