My dive computer is too conservative, what can I do ?

[LFMarm]

If you want to be in control of conservatism and decide on the fly how to change it based on diving conditions (temperature, buddies, etc), get a computer running Bühlmann with GFs you can change and learn what they mean. Shearwater is an option but there are also cheaper alternatives.

Even if not interested in technical diving, I believe that understanding decompression and how to adapt the algorithm to your needs or environmental conditions is importante for your safety. I have seen many NDL divers take risky decisions while thinking they were conservative by blindly following their computers. This forum has plenty of threads on the topic, including some by world leading experts in this field.

 

[ofg-1]

Computer issue? I have a hammer, I can fix it.

 

[Allen-1]

Computer issue? I have a hammer, I can fix it.

If that doesn't work, get a bigger hammer.
If that still doesn't work - it's probably electrical.

 

[Edward3c]

If that doesn't work, get a bigger hammer.
If that still doesn't work - it's probably electrical.

The words of a mechanical engineer.

 

[halocline]

Even if not interested in technical diving, I believe that understanding decompression and how to adapt the algorithm to your needs or environmental conditions is importante for your safety.

This is the right answer; anyone who is going to dive regularly should try to learn the basics of decompression theory, and get a sense for how the algorithms behave in situations of ‘light’ deco diving. Those are the kind of grey area dives where recreational divers might find themselves, and who knows, maybe their computer decides to go belly up just at the wrong time.

A long time ago, when I was taking the DM class, I had the PADI encyclopedia of recreational diving, and there’s a chapter in there that does a good job explaining the basics of compartment theory for divers that don’t know anything about decompression diving. I don’t even know if that book is still published, I lost mine at least 20 years ago.

Divers really should understand enough to guide their own behavior and have the ability to minimize their risks of DCS. As an example, a 7-10 minute stop at 10 feet is amazingly effective at clearing N2 on dives that ‘dip into’ deco obligations. Just knowing that gives a diver an extra margin of safety when in doubt.

I never like these ‘buy a different computer’ threads. Everyone loves shearwater, and for technical diving they are very well designed. But it’s hardly the point for newish drivers that are first learning about how to manage their profiles and dive safely.

 

[John Bantin]

I've been using Suunto computers since they went over to push-buttons (a long time ago) and I've done some serious dives (eg. Bikini atoll, San Francisco Maru inside, dives with Rob Palmer etc) ). I just do the deco stops they demand. Maybe that's why I'm still healthy at 77 years old?

 

[Stoo]

Hello hello,

Here's my problem. I've just bought a Suunto Zoop Novo,

You could have stopped there. Zoops are inexpensive, entry level computers that are notoriously conservative. I think they’re designed for resort course graduates so that no matter how badly they mess up their profile, they won’t get bent.

Sell it get something else.

 

[ancient diver]

It would be nice if some testing agency would turn the "conservative" and "liberal" dive computer ratings into empirical numbers such as minutes different from NDL on a recognized set of dive tables [ PADI, NOAA, NAUI, USN, CMAS]. This would be useful for recreational divers who do not plan to do decompression diving. I live and dive in a location where I see a lot of recreational divers every day who look a bit like deer caught in the headlights when the words "adjustable gradient factors" are brought up.

A very very long time ago, my first dive computer was an SOS analog computer. Luckily, I lived very close to a USN submarine escape training facility and the Navy diving detachment. Several of us ran the brand new first of its kind SOS computer thru its paces vs the USN tables in the Navy dive chamber. Ever since then, I would "test" my new dive computers [Oceanic, Suunto, US Divers and others I may have forgotten against Navy tables just to make sure I had a computer that wasn't going to "bust" the Navy tables. My present computer, a Shearwater Tern , I haven't tested since I no longer have access to test gear. However, by now, I think I may have a reasonable handle on setting up conservative gradient factors for a 77 year old recreational diver [me]. If I ever have the chance, I'll also test my Shearwater.

In my real world occupation of 31 years [Naval Aviation] we used real charts, real numbers, and real performance tables developed from real empirical testing.

How we let the dive industry talk us into "liberal" and "conservative" is beyond me. It's like rating the lemmings headed for the cliff as "fast" and "slow" when what you're really interested in is whether or not they go over the cliff.

 

[shoredivr]

According to the online manual, you can adjust the algorithm to 1 of 3 options under Personal Adjustment:

0 Ideal conditions (default value).
1 Conservative. Some risk factors or conditions exist.
2 More conservative. Several risk factors or conditions
exist.

To change the personal and altitude adjustment settings:
1. While in a dive mode, keep [DOWN] pressed.
2. Press [SELECT] to enter Personal Altitude settings.
3. Press [UP] to change the Personal adjustment and confirm with [SELECT] .
4. Press [UP] to change the Altitude adjustment and confirm with [SELECT] .
5. Press [MODE] to exit.

Note - I don't own a Zoop (I have a Perdix) so I'm just relating what the manual says.

So in other words, one is stuck with adjusting between a conservative setting, a very conservative setting and an ultra conservative setting.

The OP should put the zoom back in the box it came with, put it on the back shelf of the dive cupboard, and buy a Shearwater anything. Problem solved.

 

[Belzelbub]

It would be nice if some testing agency would turn the "conservative" and "liberal" dive computer ratings into empirical numbers such as minutes different from NDL on a recognized set of dive tables [ PADI, NOAA, NAUI, USN, CMAS]. This would be useful for recreational divers who do not plan to do decompression diving. I live and dive in a location where I see a lot of recreational divers every day who look a bit like deer caught in the headlights when the words "adjustable gradient factors" are brought up.

Yeah, that would be great, but it’s not quite so simple. For dive computers running a straight implementation of Buhlmann or another open source algorithm, it’s easy. Online planners can give you NDL at different depths with different settings.

For a first clean dive, the dive computer’s planning function will give the diver an idea of what to expect. That could be compared to a table if so inclined. It’s the subsequent dives that get tricky. The proprietary nature, and lack of transparency, of a lot of DC algorithms make it really hard to predict what a subsequent dive NDL will be, as the manufacturer doesn’t provide details on how it treats certain factors.

I think the closest we’ll get is a @scubadada spreadsheet. IIRC his spreadsheet compares NDL for Buhlmann, DSAT, and PZ+. I think it also shows PADI and maybe US Navy dive tables as well.