Controlling ascent rates and weighting

[tbone1004]

i wouldn't say yesterday was a bust at all.

You learned about how much weight you need to comfortably get down from the surface.

You learned how much suit compression matters as you descent which is why many deem drysuits necessary for diving at any depth. You can dive 7mm's as deep as you are comfortable, but my personal rule is 100ft. Any deeper is drysuit territory as much as I hate to dive dry.

You learned about the differences in comfort when you are squeezed by a thick suit, have a hood on, and gloves. Not sure how thick your hood and gloves were, but I personally hate gloves so down to about 55F I wear only 3mm's and deal with my hands being a bit cold. Hoods don't bother me, but you have to learn how your body works and how to adjust your position in the water with small movements of your core muscles because you have limited movement with your neck.

You learned that going a year without being in the water, especially as an inexperienced diver is something that you probably don't want to repeat and the discomfort of diving in heavy exposure protection may be worth it for the freedom that you'll feel when you dive in warm water.

Not a bust at all in my opinion, and likely one of the most productive dives that you've had to date. Not the most enjoyable obviously, but it was very productive by the sound of it and that matters

 

[tlehman]

Thanks, tbone. I wasn't clear when I said bust. Between weighting, struggling with equipment and bulky exposure gear, and my buddy's initial ear clearing problems, we ended up with very little actual underwater time. Frankly I was exhausted by the time we were really ready to dive. I did learn a lot in the process, however. I'm going to make some changes to attachments and things on my BCD and think about options to lessen the bulk part. As you say, it was a learning experience and that's particularly important at my stage in diving. Thanks for reminding me.

 

[kr2y5]

Have you considered using an SMB? It is an incredibly useful skill on its own. In addition, it gives you a reference line, and a reference for the speed of ascent. If ascent is too fast, the line will go slack.

 

[tlehman]

Using a SMB as a tool to help managing ascent is an interesting idea. I have a DAN SMB that is designed for surface use only (i.e., manually inflate) primarily to be visible to if I surface to far from the dive boat. A friend suggested I get one that can be deployed at depth as you're suggesting to alert any boating traffic that I'm coming up. I hadn't though of using it as you are suggesting. Interesting.

 

[outofofficebrb]

I agree, I wouldn't say it was totally a bust. These are the growing pains of diving...figuring out what works for you and what doesn't. I also find the first 10 feet or so the most challenging when I'm weighted properly. I just have to tell myself -- exhale a little bit more than you usually will and that usually does the trick to help get me started. Then all is well after.

 

[RainPilot]

The neutral weighting is meant to keep you with an empty wing/BCD, an empty tank and half full lungs at a hover just below the surface. The problem is that most people do their weight adjustments at the start of the dive and rarely do it with an empty tank as its inconvenient to do.

Thus they start the dive fine, and then by the end of the dive they are underweighted and cant hold a stop in shallow water. If you can, do a weighting check with a 500psi tank in the gear that you are planning to dive with and that should help.

If you can't, someone on here will be able to give you the buoyancy change on the tanks you dive with, I don't know the US tanks very well. If memory serves, there is about a 6lb difference on a AL80 so if you are neutrally weighted at the start of the dive you will need to add 6 lbs of detachable weight to compensate for the gas you will use up during the dive.

ALL the divers that have come to me for help with your problem in the past have not weighted for an empty tank, doesn't seem to be covered practically in most OW classes aside from a mention.

 

[Freewillow]

when you try to go down from the surface, make sure that you are emptying your lungs. A lot of new divers don't .

 

[Neilwood]

For those struggling to get down from the surface after reducing weighting I was given a great tip by my instructor for it.

As you are about to descend, breathe in then fin kick up (sounds daft eh?). As you reach the peak start to exhale fully and your momentum will carry you down ( ideally getting back to your original position with empty lungs but with downward momentum to help you).

It does work.

 

[Agility]

If you really want to enjoy cold water diving, a drysuit is the way to go

 

[Bob DBF]

The neutral weighting is meant to keep you with an empty wing/BCD, an empty tank and half full lungs at a hover just below the surface. The problem is that most people do their weight adjustments at the start of the dive and rarely do it with an empty tank as its inconvenient to do.

Very good advice, I do a weight check and adjust for neutral with an empty BC, at 15', with about 500# in the tank. In this way I will be able to maintain a safety stop using lung control only and be slightly positive on the surface with an empty BC.

If you can't, someone on here will be able to give you the buoyancy change on the tanks you dive with, I don't know the US tanks very well. If memory serves, there is about a 6lb difference on a AL80 so if you are neutrally weighted at the start of the dive you will need to add 6 lbs of detachable weight to compensate for the gas you will use up during the dive.

There are various places such as huronscuba.com that give tank specifications. The difference in weight you need would be about the difference in the empty buoyancy numbers. If the air at 500# (or whatever pressure you choose) between the two tank is more than a couple of pounds, then adjust for the air weight. For a change between a PST HP100 to an AL80 add about 5#, but from a Faber MP100 to an AL 80 is adding over 11#.


Bob