Did everything right ( I think) still, buddy got bent??

[DiveBandit]

I've got the profiles from the bent divers computer if anybody is interested in seeing them. There in PDF format

 

[lamont]

On sunday, dive #1 you went from 100-120 feet to 20 fairly rapidly (80 feet in less than 4 minutes, so faster than 20 fpm). It would have been better to slow down that ascent rate to 10fpm after hitting around 50-60 fsw. Then you did a long hang at 20 fsw, but bounced down to 40 fsw and then went from 40 fsw to the surface in what looks like about 2.5 minutes. Your computer only track dissolved gas and not free phase, and what you're doing here has components of a sawtooth profile rather than a decompression profile. At the 20 foot stop you are offgassing in bubble form as well as through diffusion and that additional free phase gas load is not tracked by your computer and your computer cannot model what happens in your body with that bounce down to 40 at the end.

You are making a huge mistake here which is thinking "decompression is over, it doesn't matter what i do now" and that is *wrong*. You need to continue letting off the pressure slowly to the surface and not figure the decompression is over just because a table or a computer says that you're 'done'. Its not over until you're out of the water, and then you vigorously bubble in free phase form for an hour or two which *then* completes the bulk of the decompression.

Dive #2 isn't bad in and of itself, except that coming off the back of the previous dive and with no surface interval to speak of, you're going from 55 fsw to the surface in 5 minutes, which is a 10 fpm rate. You're also going insufficiently deep to crush the free phase bubble shower which occured immediately after dive #1 and was interrupted by the descent. So probably you've got a bunch of large free phase gas bubbles which actually loadup as the dissolved gas loads up during this dive and then re-expand and are not eliminated by the insufficient deco.

Dive #3 is a bounce dive and after feeling bent after dive #2 its only going to make things worse..

 

[lamont]

Also, dive #1 on saturday you went from 100 fsw and multileveled up to 60->50 following a curve getting gradually shallower which is fantastic. But then you clearly decided to call the dive and your computers were telling you to ascend to 20 feet so you shot up there in about a minute. The biggest problem here is that you are following your computer blindly and nobody has taught you how to do decompression properly. And at this point you are decompressing and you need to take things a little slower. Once you've started offgassing from tissues you really shouldn't exceed 10 fpm ascent rates (1 minute stops every 10 feet, or 30 second moves + 30 second stops every 10 feet).

EDIT: Additionally, you did an insufficiently long surface interval and then went back down and it looks like you did ascent drills or a dive where you were bouncing betwen 30, 20, 10 fsw depths. Basically you just did a dive where you got some decent gas loading (~100 fsw for 20-30 mins) and then when you hit the surface you immediately drop back down to bounce up and down -- which can potentially cause problems. What you should have done is reverse the order of these dives. Do the drills and bounce when you've got relatively little free phase and dissolved phase gas, then take an hour surface interval, and then do the dive you did for #1 down to 100 fsw which will actually clean up from the dive doing drills.

 

[Seadeuce]

Glad you're both okay.

I had a look at the profiles posted. I believe there is a simple answer to why you suffered a "hit".

One can go into all the deco analyses concerning your profiles and SIs till doomsday and you will not become a safer diver.

The MANAGEMENT of your dive profile and the short SIs are at the basis of your problem IMO.

You did seven dives over three days. The first was to ascertain your SAC rate - why?
If you have over 200 dives done (according to your C.P.) then you should not need to do an SAC check; you should already know.
I also notice the last dive was number 54 on the Suunto dive manager.
How does that relate to over 200?

Back to my first point - on dive no. 2 the profile you did was the best of all seven.
None of the others comes close.

You know the drill - reach max. depth early, from then on dive your ASCENT. IOW once you begin to climb do not dip below again. It seems as if you were following the contours of the sea bottom.
Why not stay a few feet above the bottom and follow a horizontal path even though the bottom is irregular?

This "contouring" seems to be present in most of your dives.

After reaching safety stop depth I see you have dipped down again on a couple of dives. Provocative at best.

As to the SIs - there are recommended minimums by different tables with different agencies, usually based on HOURS not MINUTES!! 'Nuff said.

I would seriously question the credibility of the instructor who did this type of diving. No amount of magic gas mix or deco stops will compensate for the yo-yo profiles you followed, while ongassing for the slower tissues on the shallower dives.

I am surprised you both didn't get hit.

Take responsibility for dive management in every dive you do and do not blindly follow some "instructor" who is compromising your health, and future diving, by his incompetence.

I wish you well.

Seadeuce
Nitrox Instructor/ERD

 

[jupitermermaid]

Also, dive #1 on saturday you went from 100 fsw and multileveled up to 60->50 following a curve getting gradually shallower which is fantastic. But then you clearly decided to call the dive and your computers were telling you to ascend to 20 feet so you shot up there in about a minute. The biggest problem here is that you are following your computer blindly and nobody has taught you how to do decompression properly. And at this point you are decompressing and you need to take things a little slower. Once you've started offgassing from tissues you really shouldn't exceed 10 fpm ascent rates (1 minute stops every 10 feet, or 30 second moves + 30 second stops every 10 feet).

EDIT: Additionally, you did an insufficiently long surface interval and then went back down and it looks like you did ascent drills or a dive where you were bouncing betwen 30, 20, 10 fsw depths. Basically you just did a dive where you got some decent gas loading (~100 fsw for 20-30 mins) and then when you hit the surface you immediately drop back down to bounce up and down -- which can potentially cause problems. What you should have done is reverse the order of these dives. Do the drills and bounce when you've got relatively little free phase and dissolved phase gas, then take an hour surface interval, and then do the dive you did for #1 down to 100 fsw which will actually clean up from the dive doing drills.

Lamont,

I appreciate your civility in acknowledging that no one taught the OP how to do decompression dives properly rather than attack them for "not knowing something they should have." We all make mistakes, we all do things because we don't know any better, and there are a lot of things we "should" know but don't due to various conditions.

That's one of the things I like about SB.....there is so much information and knowledge to be garnished from here. It would be nice if everyone was willing to share information they have rather than attacking "ignorance." We might all learn a little (or a lot) more because we wouldn't be afraid to post our questions on the boards.

Thanks.

 

[DiveBandit]

Thx Jupitermaid... Long time no sea

Just to clarify some more. The computer is the bent divers. I had used it for a while then gave it to him when I upgraded. I didn't always have a computer so the number of dives on the computer has no corilation to how many dives I actually have under my belt.

I have to take responsibility for the short SI's. In heinsite (which is always 20/20) I had a nagging feeling they were too short, but I guess being with an instructor i've used before and have come to trust I let my guard down, my bad. Lesson learned.

 

[jupitermermaid]

Good to run into you again, Narcosis. Isn't it funny how we usually seem to trust other peoples' judgment above our own, even when we "feel" something isn't' right? It's natural to feel that an "instructor" knows more than we do. I find this instrumental in my work (as a middle school teacher) to let my students know that I am not omnipotent and allow them to question anything they don't understand or take issue with to promote growth rather than have a "ego" of "I'm the teacher...I know best" BS. Hindsight is always 20/20....why we can't fall back on it is a question I'll take to the afterlife with me....lol. I'm glad YOU'RE OK, and hope everything else works out for the best. Lessons are good to learn, as long as we are willing to learn.

Let's go diving sometime!!!!

 

[z3r0c00l]

Surface interval is your friend - it not only keeps you safe, it also increases the amount of diving you can do! Sounds like win-win to me! Take an hour after a decompression dive. Take lunch, drink that bottle of water slowly... Listen to a dozen songs in the ipod...

I dont see a safety stop in most of these dives (sunday 2 looked like one) or even a 10 foot decompression stop on sat1 - your first decompression dive ever! When are you going to be more conservative but on your first time : ) On Sunday 1 it looks like just a 20 ft stop and a run to the surface, but most decompression I see starts with 10 ft stops and then goes to 20s and up. Anyway to your credit (or the bent buddy), you guys did a nice 7 Min 40 ft stop in that Sat1 dive, and an ultra long 20 ft dive for sun1 which should have really helped keep things safe - but these do not take the place of a 10 (or 15 in heavy seas) foot stop.

 

[Kingpatzer]

I don't even pretend to know enough to comment on the specific dives. But my favorite instructor gave me great advice on my first ever class, and I've followed it ever since. He said something like:

"I'm human. I make mistakes. I will do my best to not lead you astray. But if you ever hear me tell you to do something that you know is wrong, call me on it. You are in charge of you on every dive. I'm here to guide you and give you the knowledge you need to dive safely, but to stay alive is your job and to be safe you need to make the right choices for yourself."

 

[sea nmf]

Hey folks, thanks for the info thus far.

. We just happened to also be wearing our Sunnto computers which didn't show any deco time by the time we got to 20 feet, thats why I said we did the stops even though the computer said we didn't neet to. I figured the SI's were kinda short, but i figured the instructor knew what he was doing.

Did you computers give you the OK to dive your next profiles based on its surface interval? Did you just go with what the instructor said and not check?

These are serious questions, I'm not slamming you. It's just that you said you had Suuntos.