Freaking out about unintentional ascent

[oddible]

So I just completed my 4 dives for my open water PADI cert. In Vancouver, in a dry suit (which most definitely contributed to the issues I raise below, but I don't want this post to be about dry suit issues). It wasn't uneventful. First several of use were under-weighted and couldn't descend. After hopping back out of the water and filling our BC pockets with weights we managed to get down. The second day was better as we prepared with a more appropriate amount of weight. Still, there were a couple instances of students who randomly started floating to the surface while swimming around (my wife being one of them). This freaked me out a bit at first but last night I was thinking of the physiological issues and wanted to post here for a check-in.

Technically, in a no-decompression dive, there should be no issues with these unintended ascents as long as the ascent rate doesn't exceed dangerous limits (18m/min), right? The problem arises when someone exceeds an appropriate ascent rate. The other problem here is that the likelihood of stopping for a 3min break at 3 meters is pretty slim if the diver has lost buoyancy control to the point where they are ascending from the bottom. Since technically a no-decompression dive doesn't require a 3 min safety stop this also shouldn't cause a problem though a 3 min stop is recommended, right?

All of my training has stuck the fear of death in me about unintentional ascents and I'm just trying to gain some perspective. While a 3min safety stop is there to minimize the possibility of getting bent, as long as a safe rate of ascent is maintained, we're not going to die in a condition of an unintended ascent?

I exhausted my BCD, exhaled, and grabbed her every time I saw her floating away but it wasn't always enough to keep us from still moving skyward. Kept an eye on my computer and never exceeded a safe rate of ascent.

 

[divebunny13]

Oddible, where was your instructor when all this was happening?

 

[*dave*]

I wouldn't be overly concerned. If there were any issues, you wouldn't likely be posting right now.

While 30fpm is an ascent rate we strive for, there was a time when the acceptable rate was 60 fpm and I can assure you it was exceeded many times, by many people without issue.

Training dives are typically short and shallow, so you don't accrue much in the way of Nitrogen loading. The primary issue is over expansion injury due to holding your breath on ascent. If you hold your breath, it doesn't matter how slow you ascend.

 

[oddible]

Instructors were with us and grabbed us when this started happening. I'm more concerned for our upcoming trip to Belize where we won't have our PADI instructor at 1 per 3 people and will be more on our own.

 

[*dave*]

Instructors were with us and grabbed us when this started happening. I'm more concerned for our upcoming trip to Belize where we won't have our PADI instructor at 1 per 3 people and will be more on our own.

You won't be diving dry in Belize. Buoyancy will be much easier controlling only one source of buoyancy, but do take time to do a proper weight check.

Are you certified now? From your post, it appears so. How do you feel about your course? Did you take the course to get certified or to learn how to dive comfortably? If you took the course to learn how to dive, you were sold short and they should make it right by working with you until you are comfortable.

BTW, congratulations on completing your checkouts! BC diving takes some serious desire to dive, Belize... not so much. What dives do you have planned for Belize?

 

[Crush]

Diving a no-deco profile and doing a 3 min safety stop is certainly a good idea. Unfortunately, DCS is still a bit of a mystery: diving a no-deco profile and doing a safety stop for 3 min at 20 feet will not absolutely ensure that you don't suffer DCS. Similarly, it is possible that Diver A can dive a deco-obligation profile, skip deco, and suffer no outward effects. That same diver might get badly bent or die if they do the same thing on a different day.

That being said, the safety stop is recommended, but not mandatory.

Perhaps consider posting at Ask Dr. Decompression - ScubaBoard ?

 

[ianr33]

Pop to the surface from a 30 foot dive and so long as you are not holding your breath it does not matter much. Do it on the 3rd hundred foot dive of the day and it could be nasty.

Would suggest staying shallow until you KNOW you have it under control. Buoyancy will be easier in Belize where I doubt you will be wearing a drysuit!

Incidentally,how were you adjusting buoyancy on class? Did you use the drysuit or the BC??

 

[Crush]

Instructors were with us and grabbed us when this started happening. I'm more concerned for our upcoming trip to Belize where we won't have our PADI instructor at 1 per 3 people and will be more on our own.

oddible, working on your buoyancy is certainly something that you will want to do. However, while I don't know what kind of thermal protection (if any) is required in Belize, you will find a world of difference between a (7+mm wetsuit or drysuit) and a (3mm or less) wetsuit. I dove in FL with my 7mm top, but not the Farmer John bottoms - wow, what a difference. You will love warm water.

 

[Pitchblack]

Just as *dave* wrote, you will (god forbid that it happends) notice if you get bent.

As you said, a no-decompression dive is a no-decompression dive. But one should remember that there is an obligation on doing a safety stop at 5 meters for 3 minutes if the dive is deeper of equal to 30 meters or long enough to be in the grey zone for the max depth at the RPD.

Thats fact. But still, there are cases where a perfect dive profile is done and divers get bent anyway. There are many factors that contribute, and for those factors to be present one should be either careless or extremely unlucky.

I have a great example that I was thought during a decompression-chamber testride/lecture.
There is an area in Sweden called 'Bohuslän', in that area they estimate that there is over 200.000 induvidual dives done per year. And out of those 200.000 individual dives, there is an average of 12 divers per year that is threated in the closest chamber in the area and out of those 12 there are aproximately (how that now spells?) 3-4 divers who really have a decompression injury.

My 26.5 swedish krona.

 

[fisheater]

Fear not!!

Learning to dive in cold water with lots of thermal protection is hard. Buoyancy control is a bitch to learn in those circumstances. It just takes time.

Belize? Heck. You WILL NOT have buoyancy control issues there. You'll have little to no exposure protection, so little to no buoyancy shifts with depth.

I got certified in Monterey, wearing a 7mm Farmer John. Lots of buoyancy issues and unintended ascents.

I went to Hawaii for my AOL after only a single additional
local dive. I was leery of my buoyancy control as I started the course. But I discovered that, compared to tropical divers with many dives, I was a buoyancy god. Up and down, just because I wanted to and with only controlling my breathing.

Back home and I was still a buoyancy-challenged infant.

You two will great in Belize. Just don't stop diving locally. It WILL get better and easier.