What ascent speed(s) do you use after gas switching on ascent?

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In this case you need to ascend at the assumed rate in the tables or software used to derive the schedule. Moving too slow is actually a common theme I see as a DM in beginning tech divers - emotionally they think they are "safer" but the reality is that the combination of slow tissue accumulation with finite gas supplies they aren't quantitatively safer and might actually be increasing their overall risk.
I fully agree with this, especially the part about how common it is. There is a sense that the slower the ascent, the better. That is simply not true.

I was talking about this with the primary author of an agency's technical rebreather curriculum a couple of years ago. She talked about a time she was ascending along a line at a very careful standard ascent rate, but in doing so she had to pass by pretty much everyone else who was already ascending. Back on the boat, some of them commented about her super-fast ascent rate, and she had to respond that, no, she was ascending at the standard rate (9m/30F per minute), which was only fast in relation to their super slow rate. I have had pretty much the same experience myself on a number of occasions.

A number of years ago two of my friends got bent on a relatively shallow and benign deco dive. One of them happened to be using a computer in gauge mode as a bottom timer, and its log showed that they had ascended far, far more slowly from the bottom to their first stop than they had intended. (They made other mistakes they had not realized as well--when you dive using just bottom timers, you really don't have a way of comparing the dive you thought you did with the dive you actually did.)
 
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