Perdix "Adaptive" Safety Stop - What's the purpose.

[scubadada]

How did this thread from 2021 get necro'd?

Less than 4 years, just the blink of an eye

 

[rsingler]

But what's the right answer?
You saw my screenshots from the manual, but someone said four years ago that the OC Rec instructions were different.

 

[NothingClever]

Mixing decompression stops and safety stops on the same dive is a misdemeanor crime in training and education law.

 

[Don Wallar]

I'm not sure that's exactly correct.
While the computer DOES automatically switch to a 5- minute safety stop if you exceed 100 feet when set to "adaptive", the computer makes no change to TTS whether or not you have exceeded 100 feet. I note this section from the manual where it shows that TTS does not include the (not mandatory) safety stop:
View attachment 885517
As you can see in the right hand picture, with a TTS of 1 minute at 30 feet, the computer is NOT counting the gas and time required for your 3 minute safety stop. I suspect that similarly, the computer will not add two minutes to the TTS to account for the 5 minute safety stop. No-stop TTS is merely time to ascend at 30 fpm.

And in deco diving, the safety stop is not factored in at all. When you complete your ten foot stop, you are done for TTS as far as the computer is concerned, except for the time required to transit from 10 feet to the surface.
TTS is merely the total time for a 30fpm ascent, PLUS all required deco stops.

EDIT: I see that this explanation differs from others comments from four years ago. I guess it's time to compare these pics from the manual with the OC Rec explanations. Some folks are saying that the SS is added to the TTS.
I'll believe that when I see it, notwithstanding what was said four years ago.

Hi Mr. Singler. I wasn't talking about the TTS calulation. I do understand that the computer DOES NOT take a SS into account when calculating TTS. All I was doing was confirming that if you set the computer to "Adapt" it will add a 5 min SS if you exceed 100 ft on a deco dive. Of course you can surface after that deco dive once the deco stops are cleared despite the 5 min SS. If you did that there would be no penalty and the computer would be quite happy. I just suggest that if you have the time and the gas, why not. Thanks for the discussion. Appreciate your detailed reply and input. You are absolutely correct in all you said related to TTS.

 

[tursiops]

Hmmm.
The most recent Petrel3 Manual (Petrel-3_RECREATIONAL_Manual_RevC.pdf) says:

The TECHNICAL manual for the same computer says safety stops are not calculated, thus are not included in the TTS.
--------------------
For the Perdix2 the RECREATIONAL description of TTS is identical.
And the TECHNICAL manual also says a safety stop is not calculated.
--------------------
For the Perigrine, the RECREATIONAL and TECHNICAL modes are integrated in the manual, because it is primarily designed as a recreational computer. The TTS description is as above....both required deco stops and safety stops are included. If there are required deco stops, once they are completed then a safety stop begins. The TTS includes both!

--------------------
For the Teric, there is just one manual.
TTS is defined as including all deco stops and safety stops.
In OC Rec mode, the description matches that of the Peregrine....once the deco stops are completed, the safety stop counter begins and BORH are included in the TTS.
HOWEVER, in OC Tec mode, there are no safety stops, so once the deco stops are completed, no safety stop counter begins,. and the TTS includes only the deco stops.
--------------------
Wow! I've been diving my Teric in Rec Mode (to get the saety stops) and my Perdix in Tec Mode, for some of its othr display features. I don't really use TTS so never noticed the difference!
Duh.

 

[rsingler]

For the Perigrine, the RECREATIONAL and TECHNICAL modes are integrated in the manual, because it is primarily designed as a recreational computer.

Hey @tursiops . What do the pics look like on the sample dive? At the end of the dive at 15 feet does the TTS show more than ascent time (1min)?

Guess one of us will have to look at this on their next dive.

 

[tursiops]

What do the pics look like on the sample dive? At the end of the dive at 15 feet does the TTS show more than ascent time (1min)?

Depends on which Shearwater computer and which setting (Rec or Tec).

 

[tursiops]

Hmmm.
The most recent Petrel3 Manual (Petrel-3_RECREATIONAL_Manual_RevC.pdf) says:
View attachment 886281

The TECHNICAL manual for the same computer says safety stops are not calculated, thus are not included in the TTS.
--------------------
For the Perdix2 the RECREATIONAL description of TTS is identical.
And the TECHNICAL manual also says a safety stop is not calculated.
--------------------
For the Perigrine, the RECREATIONAL and TECHNICAL modes are integrated in the manual, because it is primarily designed as a recreational computer. The TTS description is as above....both required deco stops and safety stops are included. If there are required deco stops, once they are completed then a safety stop begins. The TTS includes both!
View attachment 886307

--------------------
For the Teric, there is just one manual.
TTS is defined as including all deco stops and safety stops.
In OC Rec mode, the description matches that of the Peregrine....once the deco stops are completed, the safety stop counter begins and BORH are included in the TTS.
HOWEVER, in OC Tec mode, there are no safety stops, so once the deco stops are completed, no safety stop counter begins,. and the TTS includes only the deco stops.
--------------------
Wow! I've been diving my Teric in Rec Mode (to get the saety stops) and my Perdix in Tec Mode, for some of its othr display features. I don't really use TTS so never noticed the difference!
Duh.

Addition and minor correction. The game evidently changed in 2019, so older manuals and/or non-firmware upgraded computes may be missing some of this.

Is a Safety Stop included in the TTS Calculation?
	OC Rec Mode	OC Tec Mode*
Petrel2	​	Tec Mode only No Safety Stops calculated
Perdix	Yes	No
Peregrine	Yes**	No
Teric	Yes	No

* See Version 65 Firmware Release Notes 2019-01-18
A “Deco Clear” up-counter option has been added. (All Models) Available in OC Tec, CC/BO, and OC Rec modes. In OC Rec mode it is available in place of the safety stop. Optional in Tec modes. When deco clears this counter begins counting up from 0. It is useful for timing additional padding after the mandatory decompression stops. If the dive did not need deco, then begins upon entering the safety stop zone (i.e. shallower than 20ft / 6m).
** See Version 71 Firmware Release Notes 2019-09-10
Fixed issue in OC Rec mode when the safety stop “Count Up” option was being used, where the count-up time was being added to the TTS. This issue did not affect other modes (OC Tec or CC/BO).

 

[rsingler]

@tursiops , thank you for doing this thorough analysis!

As a Perdix owner, I'll be looking for the addition of the safety stop time to the TTS on my very next dive, because this clearly flies in the face of the pictures in the Perdix manual.
That said, the statement quoted by @tursiops is indeed in the Perdix 2 manual, and the screenshots with TTS I published are not to be found in the Perdix 2 manual.

 

[tursiops]

@tursiops , thank you for doing this thorough analysis!

As a Perdix owner, I'll be looking for the addition of the safety stop time to the TTS on my very next dive, because this clearly flies in the face of the pictures in the manual.

Are you using it in REC mode?