ascent rate: how slow is too slow?

[Neilwood]

If your ascent rate is such that the NDL decreases as you ascend it is too slow.

I personally would stick with the higher end of <10m/min until I get closer to the surface when I would slow it down.

 

[rsingler]

Looks like we're getting into splitting hairs here. But for the fun of it and the benefit of the OP, I'll keep stirring the pot, because I think it relates to the question the OP was asking about rate of ascent. Talking about 3-6'/hr on sat dives is not particularly helpful.

What neilwood said.
So for #akimbo, your point is true but not relevant for no-stop diving.
For #maxbottomtime, not true.
For both of you, as related to the OP, at some slow rate of ascent at the deeper depths noted in this post (and as specifically discussed in another thread) you will find your computer assigning you a deco stop because you ran out of NDL time. Not helpful for the recreational diver.

 

[sea_otter]

Another factor to consider is whether or not you are able to comfortably make a faster (but still well controlled) ascent in the event of an air sharing emergency. It's a good thing to practice every now and again with an eye on the clock just so you know you can do it if you (hopefully never) need it.

 

[AdivingBel]

At what point is a slow ascent unproductive?

I don't know...did you see anything interesting during your slow ascent?

As long as we're talking NDL, rec diving, a really slow ascent is just going to look like additional bottom time on a multilevel dive. I do it all the time in Bonaire. Stay within your NDLs (or whatever conservative pad you choose)/gas plan, make a normal ascent to your SS (hang around a couple extra minutes, if it makes you feel better), and enjoy your dive.

 

[elgoog]

Another factor to consider is whether or not you are able to comfortably make a faster (but still well controlled) ascent in the event of an air sharing emergency.

Yeah, what she said - this is harder than it sounds as not only are you trying to be controlled and maybe a little quicker on the ascent, you have to match your buddy's ascent rate even more closely than you normally would (all while being stressed out)

 

[Blasto]

There's no rate that is too slow by itself. But "slower is better" only applies if total time at depth is kept constant (i.e. you'll have to go shallower, rather than dive for longer). That is, for instance, applicable to ascents that are part of your enjoyable dive time, like in multilevel reef or wall dives.

Past a certain point there's no gain from ascending any slower. You'll be increasing your already high GF upon surfacing for a non-useful decrease in your already low GF during the ascent.

You can take some deco calculators, set them to variously low GF, and see the suggested deco profiles (yes, even within NDL). 10 fpm is generally fine in any case.

Overall, slow ascent is most useful in the absolutely shallowest part of the dive, such as around and after the safety stop. Get shallow quick, do a longer stop, or two stops for a deeper dive, ascend slowly from there. But going too slow right near the surface puts you at greater risk from boats and it's more difficult to maintain a slow ascent rate there. In any case, don't linger or go slow at depth.

 

[Aviyes]

Just slow enough that your computer doesn't scold you during ascent. They can be really mean!!

 

[RainPilot]

A min deco ascent strategy we use for rec diving involves a 10' per min sustained ascent, from 10' and shallower it's as slow as practical. No problem with the OP ascent plan, it's when you go waaay slower that it turns into a multi level dive.

 

[dmaziuk]

I don't know...did you see anything interesting during your slow ascent?

As long as we're talking NDL, rec diving, a really slow ascent is just going to look like additional bottom time on a multilevel dive. I do it all the time in Bonaire. Stay within your NDLs (or whatever conservative pad you choose)/gas plan, make a normal ascent to your SS (hang around a couple extra minutes, if it makes you feel better), and enjoy your dive.

Yes but many/most sites on Bonaire you can do a "slow ascent" around the no-limit depth which at least some computers will count as off-gassing at SS rather then additional bottom time/on-gassing the slow tissue. And there's stuff to see. I think that doesn't quite works the same way if you're coming up the line from a 30m wreck in the middle of nothing.

 

[Russoft]

I think that doesn't quite works the same way if you're coming up the line from a 30m wreck in the middle of nothing.

Yeah... popping bubbles from fellow divers below you, barnacles on the rope, and maybe a barracuda or two.