Descent MK1 First 24 hours - Impressions and Issues

Guessing if it’s an inability to display NDL over 99mins 59s then this wouldn’t preclude tissue absorption at shallow depths and representation of this additional absorption if one was to descend deeper. Or indeed even demonstrating an NDL at shallow depths after absovtion meant that current NDL was sub 60 mins.

I checked with a colleague on the Descent testing team, and he indicated that --:-- is displayed when the computed NDL time is 100+ minutes. So it wouldn't be triggered directly by the current depth, but a combination of depth/time and dive profile.

Whether that's better or worse than simply maxing out at 99:59 is presumably open to interpretation. My old dive computer would simply display 99 minutes in this scenario, which isn't fundamentally different from what the Descent is doing (once you're aware of how to interpret the display).

Again, I'll try to verify this and report back in a few days.

I checked with a colleague on the Descent testing team, and he indicated that --:-- is displayed when the computed NDL time is 100+ minutes. So it wouldn't be triggered directly by the current depth, but a combination of depth/time and dive profile.

Whether that's better or worse than simply maxing out at 99:59 is presumably open to interpretation. My old dive computer would simply display 99 minutes in this scenario, which isn't fundamentally different from what the Descent is doing (once you're aware of how to interpret the display).

Again, I'll try to verify this and report back in a few days.

I did a 57 minuted dive with about 30 minutes or so spent below 40 feet, max depth of 47 feet, and my Descent continued to display --:-- for the entire dive. It never displayed an NDL number.

Garmin may need to rethink how they handle display of NDL, but the Descent should display NDL for the dive even if the diver did not plan the dive or even start dive mode. It should enter dive mode automatically, like most modern dive computers, and start displaying NDL. This is a saftey issue, and could result in an inexperienced diver going into deco because their dive computer did not tell them. I dive a Shearwater Perdix as my primary, the Descent was always intended as a backup dive computer.

Thank you for discussion on the Descent MK1 NDL. The Descent Mk1 will display -:- NDL when its over 100 minutes. This is expected behavior on the Descent Mk1. This similar functionality to many other dive computers which will either blank out the NDL, if its that high or will show 99's.

@mark_20 To answer some of your questions. The Descent Mk1 is able to start dives automatically, please refer to the below manual link for additional details:

https://www8.garmin.com/manuals/webhelp/descentmk1/EN-US/GUID-F5BB5FFC-1071-4C7B-9968-2B2D985C4574.html

As previous mentioned in this thread, the Descent Mk1 will calculate NDL but when the NDL is greater than 99:59 it will be displayed it as --:--.

Planning a dive is not required for NDL to show, but it allows you to calculate NDL for future dives. Refer to the below manual link for additional guidance.

https://www8.garmin.com/manuals/webhelp/descentmk1/EN-US/GUID-952167E8-F2CE-439B-8D09-63794727A47B.html

@mark_20 To answer some of your questions. The Descent Mk1 is able to start dives automatically, please refer to the below manual link for additional details:

https://www8.garmin.com/manuals/webhelp/descentmk1/EN-US/GUID-F5BB5FFC-1071-4C7B-9968-2B2D985C4574.html

As previous mentioned in this thread, the Descent Mk1 will calculate NDL but when the NDL is greater than 99:59 it will be displayed it as --:--.

Planning a dive is not required for NDL to show, but it allows you to calculate NDL for future dives. Refer to the below manual link for additional guidance.

https://www8.garmin.com/manuals/webhelp/descentmk1/EN-US/GUID-952167E8-F2CE-439B-8D09-63794727A47B.html

Chris,

You missed Mark saying this:

”I did a 57 minuted dive with about 30 minutes or so spent below 40 feet, max depth of 47 feet, and my Descent continued to display --:-- for the entire dive. It never displayed an NDL number.”

Sorry, but he would have DEFINITELY had absorbed enough Nitrogen at that depth, at that time for some sort of NDL to display.

Based on the dive tables (NAUI) max time at 40’ is 130 minutes before you go into 150/5 (5min of mandatory deco time). Now I know that these dive profiles aren’t nearly as conservative as the old tables (why have a conservative option to choose from then?) but assuming Mark’s numbers are accurate which I’m sure they are, he should have had some sort of NDL displayed.

Chris,

You missed Mark saying this:

”I did a 57 minuted dive with about 30 minutes or so spent below 40 feet, max depth of 47 feet, and my Descent continued to display --:-- for the entire dive. It never displayed an NDL number.”

Sorry, but he would have DEFINITELY had absorbed enough Nitrogen at that depth, at that time for some sort of NDL to display.

Based on the dive tables (NAUI) max time at 40’ is 130 minutes before you go into 150/5 (5min of mandatory deco time). Now I know that these dive profiles aren’t nearly as conservative as the old tables (why have a conservative option to choose from then?) but assuming Mark’s numbers are accurate which I’m sure they are, he should have had some sort of NDL displayed.

Garmin contacted me asking for the FIT file from my Descent, so they could determine why I was not seeing an NDL value.

That dive was using EAN32, so I probably did not absorb enough nitrogen to get my NDL below 99:59. The PADI RDP shows a bottom time of 146 minutes for a dive to 50 feet. However, I still think the Descent should display something rather than a blank field. My Perdix just displays 99 minutes until the NDL is below that. I am also a little concerned that the documentation is a sparse on details on how the Descent works in dive mode, and that I have now been given two different explanations for why an NDL was not displayed by Garmin Tech Support. I should be in the ocean next weekend with an Open Water class and will see how the Descent works compared to my Perdix using air instead of Nitrox.

I did float two options for changing the NDL display past Garmin, never got a response.

1. Display 99:59 until the NDL is below this value. Value should probably be displayed in a different color to indicate the value is above 99:59
2. Display the NDL as Hours:Minutes until the actual NDL is below 99:59, then switch to minutes:seconds. Again this should be displayed in a different color.

And update the frigging manual to provide more information to the user on how the Descent works in dive mode.Some additional training for the Tech Support staff might also be a good start.

OK just stumbled on what I would have to call a bug in the Descent. I just realized that there is a 10 minute difference on the time of the dive between my Perdix and the Descent, with the Descent being 10 minutes longer than my Perdix. I have the end of dive time out set to 10 minutes on the Descent, it appears to be adding that time to the time of the dive. My Perdix is also set to 10 minutes, but does not add that time to the dive time once the dive has ended.

Garmin contacted me asking for the FIT file from my Descent, so they could determine why I was not seeing an NDL value.

That dive was using EAN32, so I probably did not absorb enough nitrogen to get my NDL below 99:59. The PADI RDP shows a bottom time of 146 minutes for a dive to 50 feet. However, I still think the Descent should display something rather than a blank field. My Perdix just displays 99 minutes until the NDL is below that. I am also a little concerned that the documentation is a sparse on details on how the Descent works in dive mode, and that I have now been given two different explanations for why an NDL was not displayed by Garmin Tech Support. I should be in the ocean next weekend with an Open Water class and will see how the Descent works compared to my Perdix using air instead of Nitrox.

I did float two options for changing the NDL display past Garmin, never got a response.

1. Display 99:59 until the NDL is below this value. Value should probably be displayed in a different color to indicate the value is above 99:59
2. Display the NDL as Hours:Minutes until the actual NDL is below 99:59, then switch to minutes:seconds. Again this should be displayed in a different color.

And update the frigging manual to provide more information to the user on how the Descent works in dive mode.Some additional training for the Tech Support staff might also be a good start.

Lol, next time lead with “I was using EAN32 as my mixture”. You wouldn’t have hit the NDL limit, unlike standard air. Makes better sense now.

@ Garmin- any update to the diving compass issue?