can we use VR3 for recreational dives..?

[brianstclair]

Now, did I follow the tables to the T - Nope. I don't always follow the VR3 to the T either (some deep stops it wanted have been at an inconvienent depth). Its a tool and I have to agree to the profile and information it gives. No blind faith.

This is a good point, and wasn't reflected in my earlier post. Thanks.

Brian

 

[in_cavediver]

Beyond BOW you should know how to get home from your dive plan (too much to ask in the real world, I know).

As I re-read this part of your post it dawned on me. With Rec diving, the surface is ALWAYS an option (but not necessarly the best). A valid response to a computer failure is to go to 15' or so, hang for a bit and surface. Heck, if you don't have a means to measure depth, the safety stop IS optional.

Now, rec divers riding NDL's and doing 'light' deco is another matter. They are diving above thier training and these conversations about deco and limits show that clearly.

Lastly, a good rule of thumb for diving multiple computers, dive them both and the most conservitive one is your limiting factor.

 

[Blackwood]

Many people have posted this "dings you for your deep stops" canard, but I've never been able to find a profile that does this.
When I do reasonable length deep stops, my dissolved gas model computer often clears the mandatory deco.
When I do excessively deep and long deep stops, both the pure dissolved gas models and the dual phase models appropriately add to the deco time. There are some slight differences, but nothing dramatic. Definitely not as dramatic as the effect of a rapid descent in some models.
Even though a neo-Haldanian computer shows that the ceiling depth is 10', you don't have to go zooming up there immediately.
You set the profile, the dive computer makes its best guess as to N2 loading.
As to the problem of computer failure during the ascent --- you have a gas plan that allows for a certain amount of maximum deco. You should remember what the total time to ascend was when you left the bottom. A reasonably alert diver should be able to complete his ascent and stops without difficulty, even if the computer dies during the ascent.

Yes, a competent diver can complete a dive sans computer. That wasn't my question. My question was with respect to those people who dive with multiple computers of differing variety and claim that one backs up the other. If you can't simply switch to the second when the first fails, it's not a backup (IMO). Perhaps this is a discussion about semantics.

 

[Charlie99]

MY vyper and a vytec (non DS) hits you badly for deep stops. If you make a deep stop you can see them ADD time to your shallow stop.

Most decompression dives ive done in the 35-45m range with those computers hit hard for deep stops.

It would be interesting to see how much deco time is added during your deep stops if you were to run that same profile on a real bubble model, such as VPM or the full version of RGBM, rather than a psuedo-bubble model such as Suunto RGBM.

Deep stops are a balance between further ongassing in the slower compartments vs offgassing the fastest compartments. That's true whether its a bubble model or a pure dissolved gas model. The bubble portion of a dual phase model is driven by the dissolved gas compartment model contained within the algorithm.