Descent MK1 First 24 hours - Impressions and Issues

Why do you say the NDL is out? It has matched my Perdix on every dive - at least each time I have compared them.

Here's a comparison from just one dive - I can do others. Note that the Descent was on my wrist and the Perdix on my camera rig so they weren't always at the same depth.
ciq.forums.garmin.com/.../1336447.jpg

Damn! Garmin have changed the way the forum works since yesterday... ? They can't even run a half decent forum!

I give up....

Copy and paste the following URL to see the picture:
http://atj.net.au/Dive2018031809The_Steps-NDL.jpg

Here's today's dive... again NDL between Descent and Perdix are very close (considering the Descent is on my left wrist and the Perdix is on the camera rig and I may be using my left hand to steady myself for photographs).

http://atj.net.au/Dive20180041908The_Leap-NDL.jpg

atj777, I never said that NDL is out. I said that the Descent is not logging the dive time correctly and I was not sure if this would impact their NDL calculations for subsequent dives. I never compared the NDL on a second dive between my Descent and Perdix, planned on doing that today but tweaked my back so I did not go diving.

I did a double dive today. On both dives the NDL on the Descent tracked pretty well with the Perdix. I haven't downloaded the data yet but I expect much the same as I've seen on single dives.

On a recent dive trip I was using both the Suunto D6 and the Garmin Descent. I did more diving in earlier years, but ended up to be a typical holiday diver now, so my only expectation to a dive watch is really that it looks after me during the dives, advises me on the remaining NDL time and guides me safely through the ascent (and if ever needed the decompression procedure). Here my experience and some observations :

• Basics functions - like setting the EAN, auto start, auto stop, surface mode are very similar and work perfect on both watches
  
• Dive profiles - are almost perfectly identical, e.g. dive time and depth
  
• Display – one of the reasons I bought the MK1 was because I did expect a better readability of the Garmin screen. The MK1 display does indeed provide a great contrast under water, on the other hand Garmin uses rather small fonts and the screen settings are not selectable for the Dive mode. So finally both watches are equally easy/difficult for me to read. I hoped Garmin would use larger fonts, at least for NDL and Depth.
  
• NDL - Booth units display "—" whenever the NDL is over 90minutes (or so) and almost at the same point in the dive changed from "-" to display to a number of minutes
  Single Dives tank dives - the NDL's are very similar, with conservatism set to "low" the MK1 seems a bit more conservative, with "medium" setting a bit more tolerant
  Repeat Dives - the difference between the watches (or the algorithms?) was huge now, while the D6 was at an NDL of 7minutes the MK1 was still on 37min. This seems huge knowing my tissue was already highly saturated. Our dive guides watch was at 5 Minutes at this point of the dive, however it also was a Suunto (meaning also RGBM algorithm) as well. Suunto is known to have a very conservative algorithm so I am not saying the MK1 was wrong.
  
• Erratic NDL display - especially on the repeat dive the NDL was very erratic, some few meters up or down caused a huge difference in the remaining NDL. So virtually every time I checked the NDL it was just somewhere between 37minutes and "-", this is not necessarily wrong, but definitely very confusing. On the D6 the NDL display is much more normalized what gave me more confidence.
  
• Safety Stop - is adjustable on the MK1 while hardcoded on 3 minutes on the D6, big advantage here for Garmin as Maldives rules demand a 5 minutes safety stop. Also the way the MK1 counts down and alerts if the required level if left to one direction is solved much clearer on the MK1 than on the Suunto.
  
• Garmin connect - be aware your phone requires an Internet connection to download the dive from the watch, so it was not possibly to check the dive on my phone while being on the dive boat.
  
• Dive numbers - Garmin connect numbers all dives in the order 1,2,3,4,…, even if you change the first dive to your actually dive number the next dive will be 2,3,... So you require to renumber all your dive. I guess this is a software glitch, naturally one dive should be the last dive +1.
  
• GPS - logging entry and exit locations worked like a charm.
  Some divers asked me to share the location of the dive-spot and in GC I found no way to share the location. Also in GC you have a list and a map view for all dives, however in the map view it does only display the location of the last dive, it trust it is supposed to display all dive locations recorded and listed in the list view ?
  
• MacDive connection - I collect all dives on MacDive and importing the .fit file from the MK1 worked fine. As (yet) it's only reading the .fit file, other information added in GC ( e.g. Buddy, remarks, tank pressures) are not transferred. Hope they will add synchronization with Garmin Connect soon so all information is transfered..
  

So after 3 month of using the MK1 as my overall sports watch and a one week dive trip I have mixed feelings about this watch. Certainly it's a very promising product and the best all-in-one unit I can imagine for my personal use. Still I am not yet completely convinced. What I would wish:

• Garmin needs to be aware a dive watch is more than a fitness tracker. As divers we do trust our health into the hand of these algorithms and the devices computing them. Garmin does not having a track record for dives watches and given the lack of reviews I wish they would be more proactive in their communication in order to give me my peace of mind during my dives
  - How did they test and validate the dive function ?
  - How do they make sure updates on the Fenix part of the software do not endanger the validated dive computer part ?
  
• On the Fenix part of the watch I wish they roll-out software updates for the Fenix 5x onto the MK1 as well. There are still some bugs (e.g. Calories display in combination with Stages Powermeters) what are annoying. I understand this bug eventually is going to be fixed in the next F5X update, however, will we receive this update for the MK1?
  

I hope more divers in this forum will compare the MK1 with their dive computer, specially in situations of multi-tank dives and comparing with other Bühlmann-ZHL-16c based computers.

Don’t expect answers to your questions in regards to the MK1, at least from Garmin. Garmin personnel and support has been non-existent around this MK1 forum and as the weeks and months roll on, non-existent in the online chat and phone support. They did A LOT of talking in the beginning (January) but like anything, actions speak louder than words and their lack of action speaks loud.

The first week in May will be the 4 month mark to when this watch was released.

• Display – one of the reasons I bought the MK1 was because I did expect a better readability of the Garmin screen. The MK1 display does indeed provide a great contrast under water, on the other hand Garmin uses rather small fonts and the screen settings are not selectable for the Dive mode. So finally both watches are equally easy/difficult for me to read. I hoped Garmin would use larger fonts, at least for NDL and Depth.

As I've gotten older my near sight has reduced. I now have +2.5 diopter lenses at the bottom of my mask so I can see and read my camera controls. They also work wonders on reading the display on my Descent. Also amazing for finding tiny critters, including pygmy seahorses.

• NDL - Booth units display "—" whenever the NDL is over 90minutes (or so) and almost at the same point in the dive changed from "-" to display to a number of minutes
  Single Dives tank dives - the NDL's are very similar, with conservatism set to "low" the MK1 seems a bit more conservative, with "medium" setting a bit more tolerant
  Repeat Dives - the difference between the watches (or the algorithms?) was huge now, while the D6 was at an NDL of 7minutes the MK1 was still on 37min. This seems huge knowing my tissue was already highly saturated. Our dive guides watch was at 5 Minutes at this point of the dive, however it also was a Suunto (meaning also RGBM algorithm) as well. Suunto is known to have a very conservative algorithm so I am not saying the MK1 was wrong.

Standard behaviour of RGBM algorithm. Often gives you more time on the first dive but punishes you on subsequent dives. I recommend you read some of the many threads here: https://www.scubaboard.com/community/forums/computers-gauges-watches-and-analyzers.17/ that discuss differences in algorithms.

Which is right? They are all just estimates and approximations of what happens as our bodies absorb nitrogen. As every person is different (different fitness levels, amount of fat, etc.) the algorithms are only just a guess. Even the rate of nitrogen absorption for a single person can change from day to day with many factors.

• Erratic NDL display - especially on the repeat dive the NDL was very erratic, some few meters up or down caused a huge difference in the remaining NDL. So virtually every time I checked the NDL it was just somewhere between 37minutes and "-", this is not necessarily wrong, but definitely very confusing. On the D6 the NDL display is much more normalized what gave me more confidence.

If the D6 NDL display is "more normalized", I'd be wondering if it is perhaps rounding or not telling me the true story. While I have noticed both my Descent and Perdix showing wildly varying NDLs, on a normal dive I'm only checking the Perdix every few minutes and so wouldn't see this.

• Garmin connect - be aware your phone requires an Internet connection to download the dive from the watch, so it was not possibly to check the dive on my phone while being on the dive boat.

Yeah. This one has been discussed before. Third party apps can access the data directly. For example, Diving Log 6.0 now has support for the Descent. All you need to do is connect the Descent to USB and copy the FIT files and load them into Diving Log 6.0.

• Dive numbers - Garmin connect numbers all dives in the order 1,2,3,4,…, even if you change the first dive to your actually dive number the next dive will be 2,3,... So you require to renumber all your dive. I guess this is a software glitch, naturally one dive should be the last dive +1.

The dive numbers are set by the Descent and any updates in Garmin Connect or Garmin Connect Mobile to dive numbers will not be sent back to the Descent. Most dive computers work this way, however, they provide the ability to update the next dive number on the computer itself. This is what is required here: a setting on the Descent itself to tell it what the next dive number should be.

• GPS - logging entry and exit locations worked like a charm.
  Some divers asked me to share the location of the dive-spot and in GC I found no way to share the location. Also in GC you have a list and a map view for all dives, however in the map view it does only display the location of the last dive, it trust it is supposed to display all dive locations recorded and listed in the list view ?

The coordinates are stored in the FIT file. Diving Log 6.0 extracts both the start and end coordinates. Perhaps you need to request MacDive to do the same.

So after 3 month of using the MK1 as my overall sports watch and a one week dive trip I have mixed feelings about this watch. Certainly it's a very promising product and the best all-in-one unit I can imagine for my personal use. Still I am not yet completely convinced.
It appears your Descent has worked flawlessly and pretty much as per the specifications. I'm not sure I understand way you have mixed feelings and are not convinced. Your wish list is valid but would have existed before you purchased the Descent.

I hope more divers in this forum will compare the MK1 with their dive computer, specially in situations of multi-tank dives and comparing with other Bühlmann-ZHL-16c based computers.

I am doing exactly that (see above) and find the Descent and the Perdix match very closely.

Has anyone else seen an issue with the Altitude on their Descent? My older Fenix shows it as 465 feet, my actual is about 75 feet, but the Descent shows it as 3,268 feet. I realize there is some accuracy issues using GPS for altitude, but that is still a very large difference. And for the record, this is just an observation and I never really use the altitude for much anyway.