Question about ascent incident

[Leejnd]

I missed the times and you're pretty much fine based on the times you gave, IMO you don't need to practice those buttons in the pool when you can do that in front of TV. You'll get that at the surface anyhow and the suggestion to use the string and pull is a good one. In fact I normally descend horizontally by pulling on my string. The inflate valve is the only one I use until I surface then I'll blow some air into it instead of using tank air for the BC. I try to avoid wasting Nitrox for my BC if I can.

To be honest I've made that mistake at the surface myself when I first started diving and it's not something I'd care to do at depth. After a few dives you'll have it solid especially if you stick to pulling the string to dump air.

So you use the string to vent whenever you are below the surface? How about when you are ascending...I'm supposed to be purging my BCD as I ascend, right? In my class they taught us to ascend by holding the hose above our heads and mashing down on that purge button. Is it better to be pulling the string instead? But then, that would only work if I was fully horizontal during ascent, right?

Oh, and Redhead, thanks for saying that...I do feel kinda silly, but then I do NOT intend to be one of those 80% or so who get certified and never dive again. I want to master this sport, and learn from whatever boneheaded moves I might make!

 

[Diveral]

Glad you have continued diving. the first 15-25 feet are the trickiest to control buoyancy in. Most of us have experienced difficulty at these depths while gaining experience. Keep at it, it will come and have a great time on your cruise.

AL

 

[Leejnd]

One quick question re: your floating fins. I could be wrong but I believe most fins would not be buoyant enough to cause your legs to float up. My guess, from the location of your dive, is that you were wearing a fairly thick wetsuit (7mm?) and it is not uncommon for relatively inexperienced divers wearing such suits to experience this problem. Moreover, as you ascended, your buoyancy increased, further making matters worse. Some people wear ankle weights (2lbs) and this can help however the majority don't so you can learn to keep your body position such that they should prove uneccesary.

Yep. I was wearing a full 7mm neoprene wetsuit, hood, gloves, the works. I should mention that we did our four OW dives to complete our certification in the Caribbean, wearing shorties, and I noticed the bouyancy of my fins there as well. I've asked a few people about wearing ankle weights, but I gather from some of the stuff that I've read that there's some kind of huge controversy surrounding it! (I'm still trying to figure out what's behind all the bickering I see going on on various dive-related websites...stuff about DIR, and MOF, and stroke, and all kinds of stuff that seems to inspire huge arguments, which make no sense to me!) All I know is that apparently lots of folks think that wearing ankle weights is a really bad thing! (?) Anyway, about the fins...hopefully I'll get used to the slight bouyancy and be able to deal with it after a few more dives.

As for diving in warmer waters, thanks for letting me know how much easier it'll be! I'll be going on a 19-day cruise from New Zealand through Tahiti, Bora Bora, Moorea etc. in December, and I plan on doing a lot of diving there. That's one of the reasons I'm so intent on learning all I can right now, so I'll be skilled enough there to really enjoy it.

LeeAnne

 

[TheRedHead]

I use both methods for purging my wing. Some of my larger wings are slow to purge and I want to see the glub, glub. If you use a back inflated BC, the best way to get the last bit of air out is to go vertical, lean back and tilt to the right so the inflator is at the highest point, then purge. You can see the inflator hose and the air that comes out.

You can fix floaty feet by moving the tank down or by using weights in trim pockets. You just have to experiment with the right combination of tank placement and weights. It just takes time and practice.

Everyone who posts here has done numerous silly things including stuff like forgetting essential equipment such as masks or fins before entering the water.

 

[Leejnd]

You can fix floaty feet by moving the tank down or by using weights in trim pockets. You just have to experiment with the right combination of tank placement and weights. It just takes time and practice.

So nobody's going to call me some awful scuba epithet that I don't recognize because I use little ankle weights to control my floaty feet?

Everyone who posts here has done numerous silly things including stuff like forgetting essential equipment such as masks or fins before entering the water.

That's good to know! What a relief.

 

[markfm]

Nahh, we'll call you evil things, just not to your face

My FFA was also around dive 3 -- drysuit, hadn't gotten the hang of the back purge. My takeaways were to be really good about dumping the drysuit on the way up, plus learning about the rear valve.

Similar to you, no bad effects, but a learning experience.

You'll probably be able to lose the ankle weights as your weighting and overall trim improve -- it's a pretty steep curve early on, getting the hang of things. Don't take them off until you're ready, but maybe try every couple of dives, see if you can shift those few pounds up to your BCD pockets -- ask your buddy to see if your trim is OK, or if you're still feet-high.

 

[nolatom]

No bashing, it's a common mistake and you're asking the right questions.

One of the answers it that buoyancy is way easier to control at depth than in the shallows, so don't feel bad about how hard it is to control it at 25'.

At 70', if you ascend 5', it's only about 7% of your depth, doesn't affect buoyancy much; but at 25', ascend 5' and its 20% of your depth, so it affects buoyancy a lot more. That's what happened to you. By the time you reoriented yourself from head-down (where you could've dumped air from the lower back vent valve) to head-up, you'd probably risen about 10 feet and coming up fast, so the game was really "over" by then, and you were heading for the surface. At 15', or 10', it's really hard to arrest that ascent, for the reason mentioned above, the ascent "percentage" compared to depth is just too high--you have no "brakes".

Also, as you get anxious, you breather harder and faster. Your lungs stay fuller as a result, making you even a couple of pounds "lighter" than if your breathing were more relaxed. Not what you want, but unavoidable.

By now, you know how to avoid this. Dump your air early, so you're almost slightly negative as you swim up to the shallower level. Then it's easy to put on the brakes.

 

[divingjd]

On a fast ascent from relatively shallow water, there is really a much greater threat of some kind of over-expansion injury, including arterial gas embolism, than of DCS. Remember that there is a much greater change in pressure, and buoyancy, in shallower water, which is also why it was more difficult to control your buoyancy at 25 feet. The wisdom of descending again to 15 feet is questionable. This practice, known as "in-water recompression," is pretty controversial. DAN does not recommend it. Here's the FAQ from the DAN website:

Q: In the absence of a recompression chamber, does DAN recommend treating a "bent" diver with in-water recompression?

A: DAN does not recommend that symptomatic divers be recompressed while breathing standard air in the water. In some areas of the world, divers are treated with in-water recompression because of a lack of chamber facilities.
At one time, divers were treated in recompression chambers using the U.S. Navy treatment tables and breathing air instead of oxygen. The failure rate was high. It is unlikely that in-water recompression using air is more effective than those old treatment tables. In-water recompression with the diver breathing oxygen instead of standard air has been used successfully in some areas.

However, in-water recompression has its own dangers and should not be attempted without the necessary training and equipment, or in the absence of someone who can assess the diver medically. The resources required for in-water recompression usually exceed the ability of those at the scene to properly assist the injured diver.

In-water recompression of any type is not currently recommended by DAN.​

I had to face this question myself once in a rescue situation and decided that, if something were going to go wrong, it would be better to have it happen on the surface than 15 ft. down. Symptoms of DCI may not appear immediately; they may be delayed by a few minutes or several hours. You will hear people advocate in-water recompression, but I would go with DAN on this one.

 

[Jamie_r]

Nahh, we'll call you evil things, just not to your face .

:lol:




Good to hear you were ok, how did the people on the boat react?

 

[Leejnd]

By now, you know how to avoid this. Dump your air early, so you're almost slightly negative as you swim up to the shallower level. Then it's easy to put on the brakes.

Yeah, that, and...be sure I'm pressing the RIGHT BUTTON!

Regarding the in-water recompression, I can see why it's a questionable practice. Also, if the primary risk at that point was an over-inflation injury rather than DCS (which makes sense), then would in-water recompression even have any effect?

One thing I should mention is that my buddy happened to be a medical doctor, so I felt safe in that he would probably be able to recognize any symptoms of distress. He really did a fantastic job of immediately seeing that there was a problem and taking action, and maintaining eye contact with me throughout. He even held my hand during that 10 minutes at 15'. What a guy! :sappy:

I want to thank everyone for their responses -- this really is a GREAT learning experience for me! I'm thinking that since I have had such difficulty with my "floaty feet" then I might go ahead and try some ankle weights for now, with the intention of moving them up or dropping them altogether as my experience increases. For now it's proven to be quite an annoyance, and with all the other stuff that I need to think about, I'd rather not have to also concern myself with my feet going up.

Oh, yeah, and I'll be sure to sort out which buttons to press and strings to pull and all that stuff. Thanks again everyone!

LeeAnne