CSSP Report 3/25/06

[Lukiedukie]

Today was the start of the dive season for me and I stunk up the joint. I had the honor of diving with Timeliner and Texdiveguy. The weather was actually nice for a change, clear skies just a slight breeze out of the south. The water was nice and would probally wake the dead. My gauges showed 56 degrees at 20'. The first dive was a comedy of errors on my part. The first dive I was under weighted by around around 6 lbs but that was not the biggest problem. My biggest problem was everytime I went to inhale on my primary reg I got a mouthfull of water also. This is a brand new reg frist time wet out of the box so I was little upset and my confidence was a lot shaken. After getting out and dropping more weight in, and Alan calming me down, we decened on the plane and worked our way around the wall where I really started to have bouyance control issues with the 7mm farmer john. I have to thank Alan and Frank for there paitence with me on this dive as I was all over the place. Alan Had to catch me as I was shooting to the surface from around 35'. After I slammed into the bottom for the third time in 33 mintues I thumbed the dive with 1000 psi in my tank. After a safety stop we surfaced and I told them to go on and I would surface swim it in. On this first dive I was testing out alot of equipment at the same time and that was a big mistake, BP/W set up new second stage and a 7mm famer john suit.

Dive two was alot better I added alot more weight tipping the scales at 27lbs I was still a yo yo but not as bad, Alan did not need to grab me and I felt alot more under control. I still had some issues with not being able to stay down but I was able to catch myself and desend back to the proper depth and continue the dive. I felt alot better after the 50 minute dive but I still know there are alot of things I need to work on.

Oh yea about my water leaking reg I did both of these dives breathing on my bungeed octo with my primary clipped off to my right d ring. Alan and Frank stayed well with in reach of me incase I had an out of air issue so for that I have to thank them. The reg is a ScubaPro 600 and is already fixed, I called the shop I bought it from and they had a reg tech out at CSSP and they fixed it on the spot!!!!! (I wish I knew that at the start of the day LOL) The diaphragm was folded in after a ten second fix I was on my way home

The visiblity varied from around 10' to around 3' depending location and if I just swam into the bottom.

Well that is opening day for me I am looking forward to the next time I get wet to work on dailing in this set up so I can add new toys.

All in all it was a great day and I learned alot.

Thanks for reading

 

[loosebits]

I wasn't there but yo-yoing is a symptom of being overweighted, not under. Bare with me while I explain why.

Let us say you need 4 liters of air in your wing to be neutral at 99' (4 ATA - atmospheres absolute). At 99', that air is about 8 lbs positive. You ascend up to 33', that 4L will expand to 8L (assuming you neglect to vent it). It is now 16 lbs positive, an increase of 8 lbs of force sending you to the surface. On the other hand, lets say you are diving with less weight and you only need 2L of air in your wing at 99' or about 4lbs, you ascend to 33' and that air will expand to 4L or 8 lbs, an increase of only 4 lbs of buoyancy.

The same change would happen going from 33' to the surface in even less distance (the amount of pressure you're exposed to will half and the buoyancy of your wing will double in half the distance). The overweighted diver will have the hardest time controlling his/her buoyancy close to the surface because of this.

So, having a lot of air in your wing means any change in depth will mean a greater change in buoyancy. This leads to the yo-yoing.. you start to ascend a little bit and the air in your wing expands giving you even more buoyancy causing you to ascend even more. You say "whoops" and dump air to start to sink and the reverse happens- you rapidly lose buoyancy and sink like a rock... yo-yoing.

The way to minimize this is to 1) make *small* incremental adjustments to your wing as you ascend and descend and 2) reduce the amount of lead you need to float with your wing thus reducing the buoyancy change of your wing as you ascend and descend (as described above).

The symptom of being underweighted isn't yo-yoing but not being able to descend at the beginning of your dive or not being unable to stay down when you've breathed down your tank.. I don't mean unable to stay down as in yo-yoing, I mean unable to stay down as in you have to constantly kick towards the bottom to keep from surfacing. The fact that you were still at depth and "slamming into the bottom" well into your dive once your tank had lost some of its weight (the air you've been breathing) indicates you were no where near underweighted but overweighted.

Adding more weight actually made maintaining a constant depth harder but it was only improved skills that kept you in control (going easier on the inflator, making smaller adjustments).

Of course you had one more thing fighting you.. that 7mm wetsuit. A 7mm suit is going to have a large buoyancy change from 33' to the surface which means as you go from 33' to say 30' it's not just the air in your wing that is trying to send you to the surface, it is also that wetsuit expanding which means you really need to stay on top of the it and dump that air, more so than you would have to with swim trunks or a 3mm suit.

I'm sure Alan, being a DM, can testify that newly certified OW divers are notoriously overweighted. It's usually because they have a reflex to *inhale* when they start their descent. When they see that they aren't plummeting towards the bottom they add more lead until they can sink like a cinder block. Now remember, your lung capacity is probably around 6L. 6L is a lot of air, about 12 lbs of positive buoyancy. You add enough lead to be able to descend with full lungs and you will be grossly overweighted.

27 lbs is a LOT of lead. If you are diving with a steel plate, that's another 6 lbs. Its been a long time since I dove a 7mm suit so I don't remember what I used but with an AL 80 and a drysuit, I use about half that (I think, been a long time since I dove an AL 80 also).

I know the book method of doing a weight check is to use a tank with around 500 psi in it. As if we all bring empty tanks to the dive site . Here's what I would recommend next time you hit the water with that suit. Throw 10 lbs on your belt and bring another 10 or so with you (throw them on the stairs or something). Bring lots of different size weighs so you can go from 10 to 20 in 2 lb increments. Dump all the air from your wing and *EXHALE*. Can you sink? I don't mean sink like a cinder block, I mean where you slowly descend. First 5' or so will take about 15 seconds and then it will speed up after that as your wetsuit compresses. If you can't, add 2lbs.. rinse, lather, repeat until you can descend. Once you're down, we need to make sure you can stay down when your tank is closer to empty. Remember, that AL 80 on your back will swing 6 lbs from full to empty (the air in it weights 6 lbs). Swim around at 15 - 25'. If you start to feel a little light at 2000 psi, you'll need another 4 - 6 lbs. If you start feeling a little light at 1000 psi, another 2 - 4 lbs should do it. Now, we don't want you swimming around at 60' because of that wetsuit. If you're at 60' and you're feeling light, you're going to feel real light at 15' because that wetsuit is going to expand.

This should get you in the right ballpark and as you get more experience, you'll be able to ditch even more lead. Start recording (if you haven't already) everything that affects your buoyancy and if you felt over or underweighted (if your tank is empty and you still have air in your wing as you surface, you're overweighted.. if you can't stop your ascent without swimming down on the way to the surface with no air in your wing, you're underweighted). This means writing down what kind of exposure protection you had, what kind of tank you were diving and how much lead you had. You'll end up with a nice record of what you need for any specific dive and next time you're in a 7mm suit, you can just look it up. Every now and then, try ditching 2 lbs from what you've determined to be the correct weight as experience will reduce the amount of lead you need.

I hope this all makes sense and even helps

 

[texdiveguy]

Hey thanks to Frank and Luke for a nice day of diving at the pond. Hey Luke with all you had on your plate you did good. You have the basic skills down and a bit more in water time will sharpen those.....all of us started at the 'beginning' in our scuba careers and thru help from others and just plain practice of diving we all progress....and you will do great....hey, scuba is a continual learning sport....always something new to learn,,,,we are all truly students! Your second dive was much better...see already you made progress.... and whats awesome is your desire to dive several times a month thru this season--that is great. I look forward to diving again with you soon,,,lets 'do it'.

 

[Lukiedukie]

The 27lbs was not all lead in that 27lbs I was including the 11 lbs of the ss plate and STA. I had 8 lbs in soft lead in pockets on my waist belt the rest of my weight was on my belt. I think I was maybe a couple lbs over weighted and my trim was off, I was felt like my feet where always lower then my head this is always been a problem for me. On the frist dive I could not decend with out the use of the buoy line attached to the plane untill I got to around 15 feet after that I seemed to be okay. I am going to ahve to work on getting geared up and makeing sure I can reach that rear dump before I get in the water. I could not reach the bottom dump on the wing on both dives as the string was up between the wing and plate.

Hey all in all it was a good day, I fully admit I was pissed at myself after the frist dive and there was no way I was not going to do the second dive. Ihad been out of the water since July and thing where not going the way they would have in July. If you get thrown off the horse you got to get right back on, I am just hopping that the third dive will be better and not a reversal.

I will be diving at least twice a month from now on though out the year

 

[Lukiedukie]

Hey thanks to Frank and Luke for a nice day of diving at the pond. Hey Luke with all you had on your plate you did good. You have the basic skills down and a bit more in water time will sharpen those.....all of us started at the 'beginning' in our scuba careers and thru help from others and just plain practice of diving we all progress....and you will do great....hey, scuba is a continual learning sport....always something new to learn,,,,we are all truly students! Your second dive was much better...see already you made progress.... and whats awesome is your desire to dive several times a month thru this season--that is great. I look forward to diving again with you soon,,,lets 'do it'.

Just let me know when and where. If I am not stuck working I am there.

 

[humanphibian]

Luke, check your PM's

 

[Debraw]

I just got back from diving CSSP. Pretty good visibility probably 12 feet or better. Not perfectly clearly, little cloudy but clearer against the walls. I got 54 degrees as a temp. on my computer. I dove dry, first time in the drysuit this year! It went great no problems. I took a few pictures and will post them ASAP.

 

[Debraw]

Here is a link to the pictures I took at CSSP today.

http://www.siscuba.com/clear_springs_scuba_park.htm

 

[texdiveguy]

Here is a link to the pictures I took at CSSP today.

http://www.siscuba.com/clear_springs_scuba_park.htm

Debra those are some nice pictures!

 

[Lukiedukie]

Luke, check your PM's

I did I got nothing from so please resend