Safety stops when monitoring SurGF

[JohnN]

I've just recently configured my Perdix to display GF99 and SurGF in OC Tec. These are no-deco dives using the default 85/85 gradient factors. Typically when I hit 20', SurGF was around 60% and the display was showing "Clear" where it would if I was in OC Rec and did a 3-minute safety stop.

So the question: Under these circumstances, is a 3-minute pause really warranted at 20'?

 

[davehicks]

Yes, do a safety stop. And you can change the OC Tec settings so you get a 3-minute clock. While 60% still has a good buffer, you are much better off doing a few minutes between 20 and 10 feet. The SurGF is really good for telling you when you might want to do more than 3 minutes, or if in a non-optimal situation it would be reasonable to cut your safety stop short.

Absent some extraordinary circumstances, you should always to the safety stop.

 

[inquis]

A safety stop is optional for all NDL dives. The biggest advantage IMO is to reset the ascent speed and hopefully keep it low the rest of the way up. If I was bored or cold, I wouldn't spend all 3 mins there if surfGF was already 60. Otherwise, it's a good opportunity to practice buoyancy control, verify your weighting, etc.

 

[davehicks]

A safety stop is optional for all NDL dives. The biggest advantage IMO is to reset the ascent speed and hopefully keep it low the rest of the way up. If I was bored or cold, I wouldn't spend all 3 mins there if surfGF was already 60. Otherwise, it's a good opportunity to practice buoyancy control, verify your weighting, etc.

Boredom is not a good excuse to skip a safety stop. What other corners are you skipping because you can't be bothered? Maybe take up reading as a hobby? Fewer life-threatening consequences if you skip to the end of the book.

 

[iointerrupt]

Personal judgement call.

For myself, I'm happy to omit the safety stop with a SurfGF below 50%. If I'm that low, I've probably been shallow for some time anyway. But that's what I think is right for me, you get to pick whatever number you think is right for you.

And it does depend on the situation, if there is some compelling reason to get out with a higher SurfGF, I may. Conversely, if things are nice, I may try to drive SurfGF as low as I can get it.

The 3-minute 15ft/5m safety stop pre-dates Gradient Factors. There is no inherit magic to it, and having SurfGF as a tool changes ones view into the dive. I recommend doing some safety stops while watching SurfGF, you may be surprised by how little actual impact it has on the numbers in the end.

 

[inquis]

Boredom is not a good excuse to skip a safety stop.

I didn't say skip it. I said boredom would be a reason for me not to STAY the ENTIRE 3 minutes when tissue loading is sitting 25 points UNDER my desired safety margin. Moreover, I did say stopping is beneficial.

As this was posted in the Technical forum, I'll shy away from the rote "always complete a safety stop" line in favor of an honest opinion as to the usefulness of that 2.5 additional minutes of offgassing in the OP's particular scenario.

 

[tursiops]

A safety stop is optional for all NDL dives.

Not according to the research that developed it, nor to the PADI RDP, nor to many operators. I'm in the Cayman Islands right now, for example, and a safety stop after ALL dives is mandatory.

 

[iointerrupt]

Pick one:

a). NDL divers may ascend to the surface un-interrupted.
b). Safety stops are Mandatory.

The standard Safety Stop may be scientifically proven to reduce incidences of decompression illness, but that hardly makes it mandatory. It is but one risk factor, among dozens, that has to be balanced when under the water.

 

[100days-a-year]

So do we now do a safety stop after actual technical dives so we don't have potential catastrophic outcomes? AFAF
I've always just followed my dive plan or computer recklessly.

 

[tursiops]

Pick one:

a). NDL divers may ascend to the surface un-interrupted.
b). Safety stops are Mandatory.

False dichotomy.