Ok. yesterday was doing a deep dive check off. air temp. 55 degrees water 45-40 degrees. Had on a 7m full suit, hood and gloves. 80 alum. tank 2800 psi and 30lbs of weight. also a small poney (agency I work for requires on deep dives). I am a pretty new diver have but feel comfortable with my equipment thus far but have never been below 50' so I was a little nervous about this deep dive. The original plan was to drop down the wall and then swim around a boat and car thats at the bottom and just see what it's like kinda thing, showing my instructor I could do it in a controled fasion and without freaking out. Like I said I was alittle nervous goung out of my comfort level and let my instructor know my concerns. I felt better decending and acending from an anchor line rather than the wall and he said no problem lets do that and I'll be beside of you and let me know if you get uncomfortable and we'll go back up. Of coruse he was like dont do anything your not comfortable with but I really trust this guy and knew if I didnt feel comfortable I was going back up. So any ways we descend I have a computer on my wrist and go down with ease and comfort. As I'm watching the depth get deeper I feel good and comfortable at about 70' My weight just changed and felt so heavy that I actually had to hold alittle tighter to the rope. Then when we got to the bottom 95' had to put small amount of air into my BC to be able to stay off the bottom and then swam around enjoying my dive in comfort and ease. Now tank at about 1500psi and started the slow acent to the safty stop. All was going well until I got above 60' and I started just going to fast to the top and realized I was passing everyone in the class but the anchor line is'nt stationary any longer so pullung on the line only pulls the rope up so I dive down and grab the wall which is about 10-15' away and hold on to it and let out the air I guess I should of out of my BC of course my instructor was by me by then, it all happened really fast. And I swam back to the line and continued to my safty stop and then to the surface without any further complications. above the surface after everyone giving the ok sign my instructor and I talked on the swim back to the bank. About the changes in pressures and bouyancy. But how do others control your ascent and decent I cant imagine yet doing that with out a referance point ie anchor line or what have you. But could this of been dangerous? What would a more experinced diver do in the situation I was in going down and up? I feel good about the dive and actually looking foward to the next check off comming up. But just wanted to share my experiance and get some input or advice.
Dangerous OR Lesson Learned?
- Thread starter MEDICJOJO
- Start date
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billtodive
Contributor
It was Dangerous, and I believe you learned your lesson. (Diving is dangerous, but you can limit the risk with skill and situational awareness). It is easier to control an ascent than to slow one.
One way to control your ascent is to vent first and swim up (once you are off the bottom).
Use your lungs in combination with your bc. Breathing deep on the lungs as you vent, shallower as you ascend a few feet. Vent again as you breather deeper. This leaves you able to control the ascent with lungs, in case you are busy with your hands.
You should be able to monitor your ascent using whatever is floating in the water column. This should be relativley easy in Tennessee. Tougher in 150' vis. Enjoy your diving and take care.
One way to control your ascent is to vent first and swim up (once you are off the bottom).
Use your lungs in combination with your bc. Breathing deep on the lungs as you vent, shallower as you ascend a few feet. Vent again as you breather deeper. This leaves you able to control the ascent with lungs, in case you are busy with your hands.
You should be able to monitor your ascent using whatever is floating in the water column. This should be relativley easy in Tennessee. Tougher in 150' vis. Enjoy your diving and take care.
fisheater
Contributor
Always strive to be neutrally buoyant.
That means that when you ascend both your wetsuit and the air in your BC will get more positive. Thus, you need to bleed air out of your BC as you go up, preferably BEFORE you start to rise faster than you can control.
Don't fret too much. With practice and experience it'll become "second nature" for you and you'll do it automatically.
That means that when you ascend both your wetsuit and the air in your BC will get more positive. Thus, you need to bleed air out of your BC as you go up, preferably BEFORE you start to rise faster than you can control.
Don't fret too much. With practice and experience it'll become "second nature" for you and you'll do it automatically.
LeadTurn_SD
Contributor
Your instructor probably went over this but here goes:
1. Is your weighting correct? Many students and new divers are OVER weighted. Your instructor can help you check. Getting correctly weighted makes controlling your buoyancy much easier.
2. With a 7mm suit, you will lose good bit of buoyancy as you descend, especially in the first 30 feet. So anticipate that you'll need to add a few squirts of air on the way down to avoid getting too negatively buoyant.
3. Before you begin your ascent, remember that your suit is going to regain its buoyancy, and that any air you've put in your BC is going to expand..... what I do is vent most of the air, and then swim up to ascend (actually I'm venting air as I begin to swim up; the key word is SWIM up, don't FLOAT up
). Again, you just need to anticipate what is going to happen as the water pressure decreases during the ascent, and be ready for it.
1. Is your weighting correct? Many students and new divers are OVER weighted. Your instructor can help you check. Getting correctly weighted makes controlling your buoyancy much easier.
2. With a 7mm suit, you will lose good bit of buoyancy as you descend, especially in the first 30 feet. So anticipate that you'll need to add a few squirts of air on the way down to avoid getting too negatively buoyant.
3. Before you begin your ascent, remember that your suit is going to regain its buoyancy, and that any air you've put in your BC is going to expand..... what I do is vent most of the air, and then swim up to ascend (actually I'm venting air as I begin to swim up; the key word is SWIM up, don't FLOAT up
). Again, you just need to anticipate what is going to happen as the water pressure decreases during the ascent, and be ready for it.
jridg
Contributor
I would call it a lesson learned. I would also enroll in a peak performance buoyancy course. This will focus on buoyancy control and allow you to feel more comfortable.
The question I have is what do you do from 50ft? The greatest expansion occurs in shallower depths - you need to control your ascent by kicking and bleeding air from the BC - if you bleed too much, simply add a little back.
As for reference - you have a depth guage - either on a computer or console - that's all the reference you need. Simply watch the depth and endeavor to control the ascent rate. It will all become easier as you garner more experience.
The question I have is what do you do from 50ft? The greatest expansion occurs in shallower depths - you need to control your ascent by kicking and bleeding air from the BC - if you bleed too much, simply add a little back.
As for reference - you have a depth guage - either on a computer or console - that's all the reference you need. Simply watch the depth and endeavor to control the ascent rate. It will all become easier as you garner more experience.
firstdive2005
Contributor
Hi medicjojo- Good job on overcoming your fears. I take it that your skills for ear clearing are excellent and you are conscious of you rate of descent. You realized you where going to hit bottom and gave a couple squirts of air into your bc for bouyancy. Good for you. That can be missed because of the excitement a sometimes people just start to kick.
So you are cruising around checking everything out, pretty cool huh. Time to go up.
Check for buddy and signal time to go and ok.
Get ready by putting your inflater in your hand.
Expel air so you become a little negative.
Start kicking slowly. Watch your depth guage for rate of ascent.
As you ascend let more air out. Never allow yourself to 'float up'.
As you reach the safety stop you will feel your bouyancy. At this point just aquirt little bits at a time to reach your bouyancy. As stated earlier what is in your lungs will affect your floating to the top. So use your lungs also.
This task comes, only with practice. You will get it ,90 percent is there now. So just reread all these posts and practice. What LeadTurn wrote is very important to know about your suit.
So you are cruising around checking everything out, pretty cool huh. Time to go up.
Check for buddy and signal time to go and ok.
Get ready by putting your inflater in your hand.
Expel air so you become a little negative.
Start kicking slowly. Watch your depth guage for rate of ascent.
As you ascend let more air out. Never allow yourself to 'float up'.
As you reach the safety stop you will feel your bouyancy. At this point just aquirt little bits at a time to reach your bouyancy. As stated earlier what is in your lungs will affect your floating to the top. So use your lungs also.
This task comes, only with practice. You will get it ,90 percent is there now. So just reread all these posts and practice. What LeadTurn wrote is very important to know about your suit.
rustyshakelford
Contributor
i dont even dive with 30 lbs in my drysuit. like others before have said check your weight, you might have had more air in your bc than you though.
brett
brett
vixtor
Contributor
If Google is right and 30lbs are ~15kg, then it is huge. To compensate this you had too much air in your BC, and having more air means there's more of "you" that expands while going up, so your buoyancy is getting positive faster.
Check your weight again, I am sure you could drop ~10-15lbs of your weight in a 7mm suit.
Check your weight again, I am sure you could drop ~10-15lbs of your weight in a 7mm suit.
irishsquid
Contributor
I don't mean to hijack, but; whereabout in Tn. are you located and where was you diving?
You know, it's possible the OP is overweighted, and it's equally possible that he's not. I use 31 lbs of weight with my drysuit and a single LP95. This has been formally weight-checked repeatedly, and it is correct.
To the OP: Buoyancy is a learned skill, not an instinctive one. You learned two good lessons here: One is that, if you get behind in venting on an ascent, it's awfully hard to get things back under control. The other is that your skills aren't quite up to deep diving yet.
My Fundies instructor had a mantra about buoyancy. "Anticipate, anticipate, anticipate." Any changes you make in the volume of gas in your BC take TIME to take effect. What happens to a lot of new divers is that they don't recognize what is happening until they are WAY off neutral, and then they vent like crazy. Either it's too late, or they DO stop the ascent, but at that point they're profoundly NEGATIVE and begin to sink again. Thus the yo-yo effect one often sees.
I got a great tip from a SB member named jonnythan, when I was struggling with the same issues. He said to take in a breath and wait until you begin to rise. Then exhale, and see if you stop, and if you don't, VENT. Doing this keeps you VERY close to neutral, but gently rising. It results in a controlled ascent rate and minimizes the chances of going ballistic. It also makes it easy to stop, if you need to -- to assist or relocate a buddy, or disentangle something, or clear your mask. It also makes a safety stop easier, because you are always so close to neutral that it is easy just to hold at a given depth.
With my drysuit, I actually find that I inhale and vent almost simultaneously to avoid building up too much of a head of steam.
This will come. But keep your dives relatively shallow (and thus your nitrogen loading low) until you're confident that you can control your ascent well.
To the OP: Buoyancy is a learned skill, not an instinctive one. You learned two good lessons here: One is that, if you get behind in venting on an ascent, it's awfully hard to get things back under control. The other is that your skills aren't quite up to deep diving yet.
My Fundies instructor had a mantra about buoyancy. "Anticipate, anticipate, anticipate." Any changes you make in the volume of gas in your BC take TIME to take effect. What happens to a lot of new divers is that they don't recognize what is happening until they are WAY off neutral, and then they vent like crazy. Either it's too late, or they DO stop the ascent, but at that point they're profoundly NEGATIVE and begin to sink again. Thus the yo-yo effect one often sees.
I got a great tip from a SB member named jonnythan, when I was struggling with the same issues. He said to take in a breath and wait until you begin to rise. Then exhale, and see if you stop, and if you don't, VENT. Doing this keeps you VERY close to neutral, but gently rising. It results in a controlled ascent rate and minimizes the chances of going ballistic. It also makes it easy to stop, if you need to -- to assist or relocate a buddy, or disentangle something, or clear your mask. It also makes a safety stop easier, because you are always so close to neutral that it is easy just to hold at a given depth.
With my drysuit, I actually find that I inhale and vent almost simultaneously to avoid building up too much of a head of steam.
This will come. But keep your dives relatively shallow (and thus your nitrogen loading low) until you're confident that you can control your ascent well.
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