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Garmin Overly Conservative NDS times

2039144
10 months ago

I just bought a Garmin Descent Mk2i

Dismayed to find that even if I set it to Lowest level of conservatism its NDS times are ludicrously overly conservative.

I've been diving over 30 years and done hundreds of deep air deco dives on old Uwatec Aladin Running Buhlman tables. Done over 1000 dives on Uwatec Aladin and nearly 1000 on Suunto Stinger plus some other computers and even tables.

PADI Recreational Tables are a good reference 30m gives 20 mins (BSAC 88 gave similar, USN on low risk gave 25min (not recreational not multi dives).

As I recall UWATEC gave 18 Min

Suunto gives 18 Mins

Both a bit more conservative but not stupidly so. I also used a Suunto Vytec in mid 2010s and it gave similar.

Jump forward a generation now my Garmin descent 2i appears to say

High Conservatism - 30m 9 mins

Medium - 30m I think it was 12 mins

Low - 30m - 15 mins

Even if I jiggle with custom GF its still 15mins 25% less than PADI tables which were already suitably conservative and ALARP.

Whats next they tell us not to dive greater than 29m??? This is crazy.

I'm beginning to think I wasted a lot of money on this computer.

  • 0 10 months ago

    100/100 GF only gives 16.5mins WTF whereas my previous computers hasd 18 and DSAT(PADI) tables were 20 mins! I cannot detune my new computer to anything like my old ones under which i literally did thousands of dives! In some ways I'd be better off diving tables again especially on square profile dives!

  • 0 10 months ago

    I'm not sure what you're complaining about. The device faithfully implements the Bühlmann ZHL-16c algorithm and gives the same results as other computers (such as Shearwater) and dive planning software that use the same algorithm. If it recommends a deco stop then you're welcome to skip it at your own risk.

    Which gas are you using for the dive plan? Most divers would use 32 nitrox at that depth.

    I'm not sure what you mean about "dive greater than 29m". I have used mine at 60m+, works fine.