How do I do a 50m bounce?

[Gombessa]

I would like to Know how his 50m dive went, seems like he should of had time to do it.

Keep an eye on CDNN then?

 

[dkatchalov]

Keep an eye on CDNN then?

So crass, yet so true!

 

[Ironman]

I want to do a 50m dive with a bottom time of say 3-4 mins. How should I go about doing this I have not done any tech training yet so deco I dont know.

You didn’t ask if it is a good idea. You asked how to do it. We all need to push our personal limits at times. I’ll give you my thoughts, based on what I know now. Yes, having the formal training is good. But, you can go to 50m without it, if you are reasonably prudent. (And, more than a few people on SB, and a whole lot of recreational divers out there, have already done it this way.) You do it by planning. Your profile says you have DM training, so the planning part will (presumably) not be new.
1. Evaluate your own performance at 40m, and decide if you are ready to go deeper. In particular, have others that you dive with evaluate your performance at 40m. Are you comfortable, are you narc’ed, what is your gas consumption like? You say you’ve been at 40m enough, which is good. How did you do? And, even if you were ‘good’ at 40m, that’s not a guarantee that you will be ‘good’ at 50m. I dive with people who are clear and competent at 40m, and say they feel like they’re smoking pot at 50m. If you feel, and act, a bit narc’ed at 40m, you might want to rethink this idea.
2. Plan your dive. Don’t just strap on a tank, drop to 50m then come back up. You can probably get away with it, but why take the chance? Nothing magical about 50m, except it is 10m deeper than 40m, you are 10m further from the surface if something goes wrong. Some people do a ‘bounce’ by dropping like a stone, then starting back up. And, some people say that narcosis is much worse when they do that. Plan to make a normal, controlled descent to 50m, plan to stay 3 minutes, plan to ascend in a normal, controlled fashion. Figure out how much gas you will need, and make sure you have at least twice that much.
Buy / beg / borrow some dive planning software. Lots of it out there. (Arguments about which ‘model’ to use are about as useful as arguments about Ford vs Chevrolet). See what you need to plan for on the ascent, in terms of stops. If you go to 50m, stay 3 minutes, and start back up, you don’t incur much of a deco obligation. With my SAC rate, a dive profile to 50m with 3 minutes at depth, then a normal ascent has me stopping at 13, 10, and 7m for a minute each. That is me, NOT you. Figure out what you need to do.
3. Evaluate the conditions where you plan to hit 50m. Warm / cold? Current / no current? Good visibility and good light / good visibility and dark / bad visibility and dark? Be prepared for the conditions. Personally, I’d do it in the good visibility, warm water, no current, daytime conditions.
4. Have the right equipment. Take a redundant air source (e.g. a 30/40 cf pony bottle), and a computer.
5. Dive it with a buddy who has been there before, and who you are comfortable with.
In the States we have a phrase, often referred to as the Last Words of a Redneck - ‘Hey, y’all, watch this!’ You can go to 50m that way. Or, you can go in a more controlled manner, and increase the likelihood of a safe, uneventful dive. There’s no guarantee, just a matter of improving the odds. Let us know how it goes.

 

[VooDooGasMan]

I R Diver, Ironman has summed it all up pretty clear, in a later post of yours being upset with SBers is why I responed to your post.

There are many divers that don't post and do this dive profile alot.
I dove with a uwatech sport last week,at 85' I found a $220 crab trap, lodged in could'nt free it,
Followed rope down steep grade like a wall to see if another trap.

At 130 I said hey this will be a ir diver profile, the rope ended at 154, I looked in a couple holes at some rockfish I was there almost a minute, made my ascent back up to 85' to free the trap.
When there I looked at air as always, computer flashed 10' so after no trap free atempt less than a minute, I ascended to the surface, at 20' ilooked at the gauge had 1300 psi on a al 80 I do a 20' stop regardless, after less than 1 mnute the 10' deco stop on the computer went away.

That is my dive profile, of a 50m dive if it helps I R Diver.

 

[dkatchalov]

I R Diver, Ironman has summed it all up pretty clear, in a later post of yours being upset with SBers is why I responed to your post.

There are many divers that don't post and do this dive profile alot.
I dove with a uwatech sport last week,at 85' I found a $220 crab trap, lodged in could'nt free it,
Followed rope down steep grade like a wall to see if another trap.

At 130 I said hey this will be a ir diver profile, the rope ended at 154, I looked in a couple holes at some rockfish I was there almost a minute, made my ascent back up to 85' to free the trap.
When there I looked at air as always, computer flashed 10' so after no trap free atempt less than a minute, I ascended to the surface, at 20' ilooked at the gauge had 1300 psi on a al 80 I do a 20' stop regardless, after less than 1 mnute the 10' deco stop on the computer went away.

That is my dive profile, of a 50m dive if it helps I R Diver.

Ok, I am a noob, but how is that "profile" supposed to help anyone complete a 50m dive?

 

[JiveMaster]

Ok, I am a noob, but how is that "profile" supposed to help anyone complete a 50m dive?

hahhahah it shows what your computer will tell you...you probably won't even be in deco by the time you get halfway through your ascent, according to your computer.

plan your dive, dive your plan.

 

[evil_xander]

I was there, early in my diving career.

We went looking for something, eventually found it deeper then we figured it would be (not to mention a couple of futile dives weekend prior to that searching on the wrong side), ended up hitting 49m bottom. It was never our plan to do it, especially not for the bragging part. Depth + very bad vis made my anxiety level rise, not to a panic level, just to the level of not feeling comfortable at all any more there. This was on a single 15L steel tank, braindead plan.

So, in short - no, straight simple open water dive will not kill you. On the other hand, there's no reason to do it, besides telling 'I did it'. It will play tricks with your mind and **** does happen...

As for myself, not interested into such dives after that one, an interesting experience in any case.

 

[BarryNL]

Hallo fellow dive folk I have decided If done enough 40m dives I want to do a 50m dive with a bottom time of say 3-4 mins. How should I go about doing this I have not done any tech training yet so deco I dont know.

Easy. Find somewhere 50m deep, descend to 50m, look around for a bit, ascend. Exactly the same way you do your 40m dives really.

Of course, you do realise that if anything goes wrong then you don't have the skills or equipment to sort it out and will probably die, don't you?

Have fun.