safety stop?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

MichaelBaranows

Contributor
Messages
849
Reaction score
5
Location
Sweeny, TX
# of dives
500 - 999
I am not really sure how to ask this question.

When is a 15' safety stop needed? After diving how deep and long. If I drop down to 30'-40' to tie off boat to I need to stop at 15' for 3 minutes. I know there is another post about considering it a dive but that doesn't matter to me cause I computer can figure out my decom.

Michael
Sweeny, TX
 
MichaelBaranows:
I am not really sure how to ask this question.

When is a 15' safety stop needed? After diving how deep and long. If I drop down to 30'-40' to tie off boat to I need to stop at 15' for 3 minutes. I know there is another post about considering it a dive but that doesn't matter to me cause I computer can figure out my deco.
Michael, I have a couple issues with your question...

1. Generally speaking, you should end each dive with a safety stop. Make it a habit and chances are one day it may be real beneficial. If you drop down to 30' to tie off a boat, (not that I know why you'd want to do that instead of simply dropping an anchor) and then immediately surface, then no - you likely don't need a safety stop after a bounce dive. The goal is to eliminate the nitrogen absorbed by your body during bottom time - if you have no bottom time, in an NDL scenario it's unlikely you have much absorption either.

2. "...because my computer can figure out my deco." This statement, and others like it, is precisely why I get chapped about questions from noobs regarding which computer they should buy. Yes, your computer can figure out your deco. But if you haven't already figured out your deco in advance, how do you know you have enough gas remaining to perform the deco that your computer prescribes?

People start depending on their computers to 'figure out their deco', which is exactly what is wrong with noobs diving with computers. They let the computer run their dive, surfacing when it tells them to. They don't plan for themselves.

You should always calculate your dives before you dive them, using either a table or using a decompression software such as V-planner. This is called 'planning the dive'. Somehow I suspect you're not to the point of planning decompression dives just yet, but you should be doing the exact same process for No Decompression Limit (NDL) dives. Planning the dive is what tells you if you need a safety stop or not. If you're close to the limit of time and depth on your table, you need a safety stop. If you're NOT, then a safety stop is often still a good idea, particularly if you're shore diving and have a reef or a beach area to poke around and look at stuff for three minutes in very shallow water.

Once you 'plan the dive', the next obligation is to 'dive the plan' - e.g. don't ignore it and go do something else, thereby requiring your computer to calculate a deco schedule for you. Dive the dive you planned.

The consequences of not doing so include one day looking at your computer, which tells you that you now need three stops (30/20/10) for a total of 11 minutes, only to discover that you're at 400 psi and you don't have enough gas to perform those stops.

Know what you're going to do before you get in the water, and then after you get in the water do what you preplanned. Life is much easier that way.

Dive safe,

Doc
 
Safety stops are never "required," by definition, but they are a very good idea. Decompression stops are required stops. I make extra (deeper) stops and I stop for longer than most.
 
Every dive is a deco dive. As decompresion is - to make things short and less complicated - saturation and desaturation of nitrogen - so you do saturate with every dive and with every mix - as long as N2 is a part of the mix and the surronding preassure is higher than 1 ata.
So the "safety stop" - how I understand it - is a sort of decompresion stop for thedives called "no deco".
If you go to real deco dives with either Minimum Deco or Ratio Deco 1:1 the last stop you do is 3 meters - and in fact the 5 meters stop doesn't exist (it's 6 meters and then 3 meters).
So for me "safety stop" is a substitute for deco stops.
As such is worth doing every time you go deeper than 5 meters.
Mania
 
I am sorry I wrote that wrong. I ment to say my computer will keep up with me "NO DECOMPRSSSION LIMIT"

There is a wreck I have dove a few times that is marked with a bouy 30' below the surface. The bouy is secured to the wreck and by hooking to the bouy we are sure the boat will stay in place. I hate pulling up a 30# anchor 100' plus 400' of rope. Plus anchors are know to move and if it hangs up someone will have to make another dive to get it loose.
 
MichaelBaranows:
There is a wreck I have dove a few times that is marked with a bouy 30' below the surface.
I wouldn't bother with a safety stop after hooking in to the submerged buoy upon arriving at the wreck, assuming that I hadn't done a dive in the last several hours.

If I had been diving early that day, I'd take 3 to 5 minutes to return to the surface.
 
If I were to do a Bounce dive for such a short time I would personally would not do a Safety Stop. BUT, if you plan your dive(s) by the RDP you will find out that any time you are within 3 pressure groups of your NDL you should do a safety stop. Like many divers I use a computer but I live by my RDP. I may not get the bottom time my computer allows me but I will be around to get bottom time. If your computer batteries die while on a dive then what. Chances are you did not start your dive checking the time since most divers depend on their computer to do everything. If your computer does bite it you don't no if exceeded any of the limits or not. The RDP has so much info on it and people forget to use it!
 
I forgot to add this. At least you thought of a safety stop. Many blow right by it
 
mania:
Every dive is a deco dive.

True, but a dive in which staged decompression is required is usually referred to as a decompression dive while a dive in which staged decompression is not required is usually referred to as a no decompression dive.

mania:
As decompresion is - to make things short and less complicated - saturation and desaturation of nitrogen - so you do saturate with every dive and with every mix - as long as N2 is a part of the mix and the surronding preassure is higher than 1 ata.

Not true. While you are moving towards saturation, most of us do not make saturation dives. Once you are saturated, addition bottom time does not affect your decompression status.

mania:
So the "safety stop" - how I understand it - is a sort of decompresion stop for thedives called "no deco".

One added in as a safety factor that probably isn't actually needed. That God, because no one made safety stops when I began diving.
 
MichaelBaranows:
I am not really sure how to ask this question.

When is a 15' safety stop needed? After diving how deep and long. If I drop down to 30'-40' to tie off boat to I need to stop at 15' for 3 minutes. I know there is another post about considering it a dive but that doesn't matter to me cause I computer can figure out my decom.

Michael
Sweeny, TX

when i've taken classes that require a lot of bounce diving down to 20-30 fsw (e.g. rescue) i've felt like crap afterwards. i expect that the problem here is that even though you're not taking on much of a gas load through perfusion into tissues, you're still shaking up gas bubbles every time you pop to the surface (e.g. any micronuclei excited at depth by excersize will grow when you pop to the surface).

imo, i'd do a stop at 20 and at 10. i wouldn't do 3 mins, but probably 1@20, 1@10 with credit for the time spent in the move up (i.e. 10 fpm ascent).
 

Back
Top Bottom