baffled by Suunto D4i info while diving vs dive log

[eab]

Hello and thanks for helping! I find the Suunto D4i user guide a bit lacking for my brain. Not enough visuals or something. More brains are better in this instance for certain.

Any thoughts on the following? Any better software than Subsurface to help me decipher what's going on? I'm on a Mac.

3 dives, first 2 on air, 3rd on Nitrox 30 but logged as air
dive 1: 110 feet, 45 minutes
SI 1:33
dive 2: 79 feet, 53 minutes
SI. 1:27
dive 3: 70 feet, 63 minutes

No alarms or flashing that I recall, no deco for any of the dives outside of the normal 3 minute safety stop. However, on the 3rd dive as I approached 15 feet, it appeared I had a 10 foot ceiling with the up and down arrows displayed and 16 minute ascent time. I can't find the image in any of the logs, so I'm working from memory and what I "logged" in my head at the time.

At no point did I see the Er in the display.

I have a second computer, an Uwatec, which had nothing unusual on the display. I'm searching for my IR stick to see if I can download from that computer to get more info, but it's not looking good.

Yes, I ascended and got on the boat at the 10 minute mark because it just didn't make sense. Later when I checked the dive history log I saw the Er, but there's not much more information.

I'm home now and looking at the dive log in Subsurface. There are yellow warning triangles, but the NDL is listed as 120 min. Some of the triangles have below floor begin or end and ceiling begin and end, but they're on the same triangle so it doesn't make sense.

Please point me anywhere that will help. I would appreciate it!

Eileen

 

[Belzelbub]

3 dives, first 2 on air, 3rd on Nitrox 30 but logged as air

Not related to your question, but why did you log dive 3 as air?

I'm home now and looking at the dive log in Subsurface. There are yellow warning triangles, but the NDL is listed as 120 min. Some of the triangles have below floor begin or end and ceiling begin and end, but they're on the same triangle so it doesn't make sense.

Can you post the profiles from Subsurface? Also, one thing to look at. I'm away from desktop Subsurface at the moment, but I seem to recall that Subsurface recalculates using Buhlmann (or VPM if selected). So the Subsurface calculation may be different from what the Dive computer calculated. I believe there is also an option to show the DC reported NDL as well, but I'm not 100% certain that that is supported for all computers.

The 120 minutes NDL doesn't sound right given those depths and dive times, though. But it would all depend on the actual profile.

If your computer didn't lock you out, then it feels you completed all your obligations. The only thing I can think of is that you incurred a slight deco obligation, but it may have cleared on the way up (or during the safety stop). Though the 16 minute ascent time sounds like the required stop would have been longer than I would expect would clear at the safety stop.

 

[eab]

Not related to your question, but why did you log dive 3 as air?

Can you post the profiles from Subsurface? Also, one thing to look at. I'm away from desktop Subsurface at the moment, but I seem to recall that Subsurface recalculates using Buhlmann (or VPM if selected). So the Subsurface calculation may be different from what the Dive computer calculated. I believe there is also an option to show the DC reported NDL as well, but I'm not 100% certain that that is supported for all computers.

The 120 minutes NDL doesn't sound right given those depths and dive times, though. But it would all depend on the actual profile.

If your computer didn't lock you out, then it feels you completed all your obligations. The only thing I can think of is that you incurred a slight deco obligation, but it may have cleared on the way up (or during the safety stop). Though the 16 minute ascent time sounds like the required stop would have been longer than I would expect would clear at the safety stop.

Thanks Brian.

I sort of fell into a deal with the Suunto when my Uwatec battery replacement took too long and the dive shop felt a little guilty. Not my 1st choice, but I'm trying to make the best of it. ;-)

I'm happy to post the dives online, but don't know how. I know I can screen shot, but I doubt that would be helpful. I'll poke around and see how to do it. Maybe export the 3 into a logbook?

My Suunto did lock me out. My Uwatec didn't. Just weird. I'm trying to get better at understanding the Suunto screens since I can't find my IR dongle for the Uwatec, but can't find anything helpful. Not knowing the Subsurface super well isn't helping either.

I usually log my nitrox dives as 21% to maintain the safety value-add of nitrox, but do watch my MOD. Make sense?

Thanks. I'll see what I can figure out and will be back.

Eileen

 

[Belzelbub]

I'm happy to post the dives online, but don't know how. I know I can screen shot, but I doubt that would be helpful. I'll poke around and see how to do it. Maybe export the 3 into a logbook?

I think a screenshot of the profile would be fine. As long as the mouse cursor is positioned at the point of the lowest NDL, the info box should show something useful. Also make sure the algorithm at the top is displayed.

In the settings under tech settings, make sure the check box for “Draw dive computer reported ceiling red” is checked.

My Suunto did lock me out. My Uwatec didn't. Just weird. I'm trying to get better at understanding the Suunto screens since I can't find my IR dongle for the Uwatec, but can't find anything helpful. Not knowing the Subsurface super well isn't helping either.

Ok. This makes more sense. I suspect you ran into the conservatism of the Suunto. Not sure why exactly.

I usually log my nitrox dives as 21% to maintain the safety value-add of nitrox, but do watch my MOD. Make sense?

Yeah. Some do that. The Suunto algorithms tend to be on the conservative side, so this may not be needed. Sounds like the conservatism and inaccurate gas mix put the Suunto into deco.

 

[eab]

In the settings under tech settings, make sure the check box for “Draw dive computer reported ceiling red” is checked.

Ok. This makes more sense. I suspect you ran into the conservatism of the Suunto. Not sure why exactly.

Yeah. Some do that. The Suunto algorithms tend to be on the conservative side, so this may not be needed. Sounds like the conservatism and inaccurate gas mix put the Suunto into deco.

Progress!

Someone suggested I download the Suunto DM5 software, and that uncovered a 0 NDL point in the dive. Searching for why I didn't hear or see the alarms ... maybe a setting I ignored?, but I'm on the right track.

Just finished my day job and cooking dinner, so I'll play around with the Subsurface options for the ceilings and see what that shows. I really want to learn the dive computer itself but knowing the Subsurface software will be quite helpful as well.

Thanks for the tip about possibly not needing the extra safety margin from the nitrox. I don't have any additional profile adjustments so that conservatism may account for the difference between the Suunto and Uwatec.

Continuing to sleuth and us/discover....

Appreciate all the info and tips!

Eileen

 

[Marie13]

If you’re on a Mac and also have an iPhone, have a look at MacDive. I couldn’t stand the user interface on Subsurface.

 

[eab]

If you’re on a Mac and also have an iPhone, have a look at MacDive. I couldn’t stand the user interface on Subsurface.

I am struggling with it so thanks! I'll check it out!

Eileen

 

[Centrals]

Thanks Brian.

I sort of fell into a deal with the Suunto when my Uwatec battery replacement took too long and the dive shop felt a little guilty. Not my 1st choice, but I'm trying to make the best of it. ;-)

I'm happy to post the dives online, but don't know how. I know I can screen shot, but I doubt that would be helpful. I'll poke around and see how to do it. Maybe export the 3 into a logbook?

My Suunto did lock me out. My Uwatec didn't. Just weird. I'm trying to get better at understanding the Suunto screens since I can't find my IR dongle for the Uwatec, but can't find anything helpful. Not knowing the Subsurface super well isn't helping either.

I usually log my nitrox dives as 21% to maintain the safety value-add of nitrox, but do watch my MOD. Make sense?

Thanks. I'll see what I can figure out and will be back.

Eileen

Eileen,
Which Uwatec computer do you have?
Sunnto'c computer is quite conservative as compared with Uwatec which uses different algorithm to calculate the ndl. This could be the reason why your Sunnto locked up and Uwatec wasn't. You should always use the conservative one as primary and the liberal one as back up.

 

[eab]

Eileen,
Which Uwatec computer do you have?
Sunnto'c computer is quite conservative as compared with Uwatec which uses different algorithm to calculate the ndl. This could be the reason why your Sunnto locked up and Uwatec wasn't. You should always use the conservative one as primary and the liberal one as back up.

I have the SmartCom. It's pretty old. Been with me for about 800+ dives now. I would suspect that one is the conservative one because the software is ancient (while I am not ).

I have heard that the Suunto is conservative. I know we used to joke about how the thermometer always rounded down a couple degrees.

I prefer to consider my Uwatec as primary because it's air integrated, but I do see the merit of having the more conservative one as the primary. When I first got the Suunto, I monitored the differences and they seemed slight, but those dives were in the coral nursery at 30' max, not in Cozumel with bottomless wall dives.

Thanks for the tip!

 

[Belzelbub]

I prefer to consider my Uwatec as primary because it's air integrated, but I do see the merit of having the more conservative one as the primary. When I first got the Suunto, I monitored the differences and they seemed slight, but those dives were in the coral nursery at 30' max, not in Cozumel with bottomless wall dives.

Generally, it is recommended that the more conservative computer is primary. Ideally, the algorithms are identical or similar enough. Most computers offer some level of conservatism factor. In the case of the Suunto, since the algorithm appears to be more conservative, you may want to confirm that conservatism is off, or on the least conservative setting.

As you suspected, they'll probably track pretty close to each other on initial dives, and dives that are pretty far from NDL.