Premature surfacing

[Web Monkey]

ok so i was doing my 3rd dive this holiday, and i used up my air VERY quickly, (probably from chasing fish in circles to do my digital photography spec), but at 800psi i let my DM know of my air situation. he said ok and continued going along.

Actually, you missed asking a good question here:

Q: "What happens when you think you're low on air and you're being ignored".

A: "A thumb is a statement, not a question." When you want to surface, it's time to go. If you show the DM your air and you're low and he doesn't seem to care, that's his problem. He's still breathing and if you continue on, you won't be. When it's time to go, it's time to go, regardless of anybody else's opinion.

When you went to the DM and showed 800PSI, you probably felt that you were getting low, which you were. Most boats want you back with 500 PSI in the tank, which meant that even from a reasonably shallow dive, and especially if you're sucking gas quickly, you were at about the right pressure for a nice slow ascent and a safety stop.

As for the weighting, you need to do a buoyancy check and see what it takes to just get you under the water with an almost empty tank and an empty BC and no finning. Anything else is just a guess.

Terry

 

[bracdiver]

this is an interesting post you made. It reminded me of my very first dive after getting certified. My dive buddy, who was also a DM, decided that my having only 500 psi was not a problem and that we should continue our dive. We were at 80' at this point. Being a new diver I was not the expert at gas conservation so after a few minutes I looked at my SPG again and I was down to 300 psi. I decided enough was enough and proceeded to get to my safety stop asap without my so called 'buddy'. I was able to get my stop compeleted and make a slow ascent the last 20' to the surface. Upon reaching the surface, I noticed that I was down to 50 psi. I can guarantee you this will never happen to me again. I follow the 'Rule of Thirds' now and forever.
The rule of thirds being: Use 1/3 of your gas out and have 1/3 of your gas left when the dive is over or at least at your saftey stop.

 

[RonFrank]

Several issues here.

The DM is NOT in control of your dive, you are. Once you hit 500psi, you should be ascending, and that is worst case. If the DM wants to push your limits, well, that's really not his call as you are responsible for your diving.

110 feet with less than 24 dives, and your last dive was 2 years ago? Do you see a pattern here? You should NOT be doing those depths with your experience. Why the Dive Op allowed that is questionable.

The BEST way to capture good images of wildlife is by waiting for them to become comfortable with your presence. Chasing fish around generally does not yield good results. I find that if I just go slowly and hang out, the fish often come to me. Chasing is the behavior of a predator. If the fish thinks of you as a predator, they are not going to be corporative.

Add weight! You are improperly weighted if you can not hold your depth at any depth. Granted you breathed your tank down a bit, but regardless, the difference between 500psi, and 300 psi is not a lot. You are under weighted, or you are not comfortable UW (quite likely). Another possibility is that you had some air trapped in your BC. In any event add some weight until you are more comfortable. It is MUCH better to be a few lbs overweighted vs. under weighted.

Since you are obviously not in control of your dive planning, then dive your computer. Stay within your NDL limits, and next time you need to ascend, do so.

So where is your buddy in all this????

 

[TSandM]

To begin with, go read Lamont's essay on rock bottom HERE. You need a rational framework on which to make decisions about what to do when your breathing supply is at a certain level, and it doesn't sound as though you have that yet.

It also sounds as though you would benefit from doing some reading on ascent strategies. I'm too lazy tonight to look up the threads, but there's one started by The Diving Preacher about computers that segues off into a nice discussion of decompression. On TDS, there are a couple of threads by Doppler on "The shape of the curve". Having an understand of what the theory is with regards to tissue compartment loading and microbubble formation will give you a much stronger basis on which to evaluate what an ascent without stops might do.

Being at 40 feet with 300 psi in the tank is, as far as I'm concerned, absolutely unacceptable, unless you did it for a very specific reason, and wth a full knowledge of what that small a gas supply might mean to you, and you were physically and mentally prepared to cope with a sudden loss of all of your breathing gas.

 

[IvIcYrusIvI]

Thanks guys for your helpful posts!

I now realise that my weghting probably was correct, but the low air situation will be avoided from now on
From now on i think i will lead myself and go the same way as the DM lol - will start to ascend at 600-800 psi (shallow dives)regardless of the DM (obviously let him know) -- actually saying that ofcourse rule of 3rds for wrecks

My DM was actually very good, especially on my wreck penetrations, as he was always checking on my air situation

IvIcYrusIvI......man that's a tough moniker...I have seen some doozies but I think you take the cake on this one

HAHA yea i know its actually cyrus but surrounded with ivi's - its a long story, but ive used it since i can remember using the internet, and so its kinda stuck with me sorry

Several issues here.
110 feet with less than 24 dives, and your last dive was 2 years ago? Do you see a pattern here? You should NOT be doing those depths with your experience. Why the Dive Op allowed that is questionable.

well 110 feet is only slightly deeper then what im certified to do (advanced open water), and when i say that was my max, i was being very conservative, as it was mostly above 90ft.

The BEST way to capture good images of wildlife is by waiting for them to become comfortable with your presence. Chasing fish around generally does not yield good results. I find that if I just go slowly and hang out, the fish often come to me. Chasing is the behavior of a predator. If the fish thinks of you as a predator, they are not going to be corporative.

I started to realise this today actually ! even managed to get a real nice picture of a HUGE turtle today (he swam straight to me) - that was the highlight of my holiday

 

[diver 85]

a little bit of background info: havent dived in 2 years, but took my refresher course, and am now doing my wreck and digital photography spec.

ok so i was doing my 3rd dive this holiday, and i used up my air VERY quickly, (probably from chasing fish in circles to do my digital photography spec), but at 800psi i let my DM know of my air situation. he said ok and continued going along.

anyways a little time passed and i noticed that i was becoming positivly boyant and had to dump all the air from my BCD to stay neutral, so i checked on my air and it was down to 300psi :11:.

now i should mention the dive was at a max depth of 60ft, but mostly at around 40ft. this was following a 110ft dive with 1hr SI.

i started to get a little paniky so i caught up with my DM and told him i need to assend ASAP, he said ok, so i started to assend with the group. As i got to around 30ft i noticed that i became positivly boyant again, as my tank was getting very low, i was unable to keep myself from surfacing, (my dive computer didnt complain about my assent rate), but this meant i missed my saftey stop.

now sorry about the length of this post, but i have some questions:

1. when ur tank is very low how do u stop urself getting positivly boyant? i had already dumped my air from my BCD. if this was from a deeper level im sure i would have suffered from DCI, and even possibly overexpansion problems

2. i know a safety stop is not necessary if im not within 3 groups of my NDL ( i think thats right) but i did deep dive about an hour before, so i probably should have done the saftey stop! obviously i didnt feel any of the symptoms of DCI, but how long should i leave it before diving again? is 24 hours generally ok?


thanks a ton!

some answers, about #1, you need to use more weight...on #2, in the 'old days', there was no such thing as a safety stops, from what you described, you were OK........Get #1 corrected & you won't have to worry about question #2 ie you'll get your SS in, just like you were taught...........GEAUX TIGERS............

 

[pir8]

i was taught that the correct weighting is that on the surface the water level should come to mid-mask, but obviously this is with a full tank, so im not so sure?

Actually you want to do your buoyancy check at the end of a dive so that you can check your weighting with a almost empty tank.

 

[Jim Kerr]

a little bit of background info: havent dived in 2 years, but took my refresher course, and am now doing my wreck and digital photography spec.

ok so i was doing my 3rd dive this holiday, and i used up my air VERY quickly, (probably from chasing fish in circles to do my digital photography spec), but at 800psi i let my DM know of my air situation. he said ok and continued going along.

anyways a little time passed and i noticed that i was becoming positivly boyant and had to dump all the air from my BCD to stay neutral, so i checked on my air and it was down to 300psi :11:.

now i should mention the dive was at a max depth of 60ft, but mostly at around 40ft. this was following a 110ft dive with 1hr SI.

i started to get a little paniky so i caught up with my DM and told him i need to assend ASAP, he said ok, so i started to assend with the group. As i got to around 30ft i noticed that i became positivly boyant again, as my tank was getting very low, i was unable to keep myself from surfacing, (my dive computer didnt complain about my assent rate), but this meant i missed my saftey stop.

now sorry about the length of this post, but i have some questions:

1. when ur tank is very low how do u stop urself getting positivly boyant? i had already dumped my air from my BCD. if this was from a deeper level im sure i would have suffered from DCI, and even possibly overexpansion problems

2. i know a safety stop is not necessary if im not within 3 groups of my NDL ( i think thats right) but i did deep dive about an hour before, so i probably should have done the saftey stop! obviously i didnt feel any of the symptoms of DCI, but how long should i leave it before diving again? is 24 hours generally ok?


thanks a ton!

Leave the camera at home for now. If you're still learning bouyancy control and how much to weight yourself then you already have a "full" plate. Just go out and get comfortable diving again before you start multitasking.

OK, you left out some very important info like exactly what depth were you at when you "let all your air out"? You said when you got to 30 fsw you got "bouyant again". This leads me to believe you were deeper than 30 fsw when you dumped your air. If this was the case did you try and vent more air at 30 fsw? You have to vent air "all" the way up. Did you tilt your shoulder up so the vent is at the highest point and try to vent any air that may be trapped?

If you did all that then yes, you were most likely under weighted. If not then you probably had air trapped in your BC so you may "not" need any more weight.

Also as others have pointed out, "you do not need anyone's permission to surface". If you are on a group dive unless it's stated in the begining that everyone will surface when the first person reaches (x) amount of air then you and your buddy should signal to the dive guide that you're going up and then "do it". The dive guide is most likely going to continue the dive with the rest of the group.

Good luck and happy diving!

 

[Jim Kerr]

Actually you want to do your buoyancy check at the end of a dive so that you can check your weighting with a almost empty tank.

That's exactly right! At 15 fsw if you dump all your air and sink a little then you know you can drop some weight. If you have trouble staying down then add a little. If you can just hang there you got it perfect.

When your weight is just right you may have to force yourself down the first few feet at the begining of the dive but that's normal. Once you have your weighting right you will find diving to be much easier.

 

[IvIcYrusIvI]

Leave the camera at home for now. If you're still learning bouyancy control and how much to weight yourself then you already have a "full" plate. Just go out and get comfortable diving again before you start multitasking.

my bouyancy control is very good when im actually down, did absolutely fine in the wreck, but jus as my tank was getting low i became positive.

OK, you left out some very important info like exactly what depth were you at when you "let all your air out"? You said when you got to 30 fsw you got "bouyant again". This leads me to believe you were deeper than 30 fsw when you dumped your air. If this was the case did you try and vent more air at 30 fsw? You have to vent air "all" the way up. Did you tilt your shoulder up so the vent is at the highest point and try to vent any air that may be trapped?

i let out all my air as soon as i started to get positively bouyant, and yea i kept trying to tilt up so that the dump valve was highest, too keep up with the air expanding.

but i will definatly check on my weighting with an empty tank and not let it get to that stage again

Good luck and happy diving!

thanks m8 u2