OK, what's the best way to descend?

[Big-t-2538]

A kelp dive....or did they stop teaching that also. You know the old feet-first SCUBA diving descent. Once you get a few feet underwater, turn over and kick your way to the bottom.

As for proper weighting, It teally helps to have a line (for weighting at the surface) & 15ft platform to work with a 750 to 500 psi tank.

 

[bwerb]

up here on the West Coast.

Ok, some answers to questions which were raised.

I dive in a tri/quad laminate drysuit so no suit compression but some definite airbubble trapping until the first few feet of water are over my head.

No, I am not blonde, but thanks for asking

I am currently using Al80's

I was planning on going out to do a 15 foot deep buoyancy check with a nearly empty tank and a bunch of weights to ensure that once all the air was out of the suit I could remain completely motionless and hover effectively. I think that doing it at the surface would result in a gross overweighting if the suit hasn't been "purged yet".

Good call on the "legs crossed thing", I never thought of that...blonde moment ut:

Lastly, great call on the "out of breath" situation prior to descent, I was finding it most difficult this weekend to submerge during my rescue course after swimming 250 meters out to find the missing diver on bottom (scenario 12, you know what I'm talking about after having just spent 5 hours doing the gear on, gear off, drills).

This board is awesome, thanks!

 

[MechDiver]

bwerb once bubbled...
I was planning on going out to do a 15 foot deep buoyancy check with a nearly empty tank and a bunch of weights to ensure that once all the air was out of the suit I could remain completely motionless and hover effectively

This may not be indicative of where you will be at after a dive. If I burp my suit prior to entering water, then purge again before/while descending, the suit is as empty as it gets. However, if I then do a "normal" dive, when I again ascend to 15', or whatever, I have more air in my suit, even though I have purged on the way up. Just the activity of the dive makes the suit somewhat more buoyant than it was when I first descended. This would be the time to do a final weight check IMO.

PHil

 

[scubatexastony]

jepuskar once bubbled...
At the start of your dive you should be a little overweighted so you should sink fairly easily, but I think thats only valid if your using some Aluminum tanks. I've noticed some Aluminum tanks are either neutral of slightly negative at 500psi..so their specs say anyway. If your using Steel than nevermind.

Swing is swing, air weighs the same in any kind of tank, what WILL make a difference is the amount of air. Neutral or negative tanks only means you have less weight to add to get negative.

Just look at the swing of equally sized (volumes at near equal pressures) tanks.


tony

 

[Jim Baldwin]

bwerb,

After making several trips to Cozumel I questioned several divemasters as to how they were diving with so little weight when many people were using 10 to 20 lbs.

I found that
#1 They are relaxed.
#2 Of course they let all the air out of their BC
#3 As they start to descent use a feet first descent and exhale all the air they can out of their lungs.

I tried this technique and being 6' 1" 180lbs I went from 15 lbs down to 4 lbs with a 3 mil shorty. I don't use any weight with just a wetsuit and a tee shirt.

Look up exhale all your air. Pause. Then as you start to sink, take a shallow breath. Exhale all the air and do this for three or four times and once you break 15 feet it's all downhill.
Be sure and go limp and relax you will watch your weight drop and your bottom time improve.
This worked for me.
Good luck.
Jim Baldwin
jbaldwin@cox-internet.com



as much as possible and

 

[greg somers]

There are some good points here. I think you are just slightly underweighted. A pound or 2, but no more.
There are some other considerations. Body gasses. Are you full of wind, drunk too much fizzy, need a good fart? When you descend you will find your body outgasses stomach gasses, farts and the like. Also body fat is lighter and any increases in weight over the winter may require more lead. If the suits a little tighter than last season, then recheck the buoyancy. (Whaddya mean...I've always been skinny @#!!*%)Heheh.
I also release trapped air. I leave my straps not fully tightened and adjust them when I have expelled the suit air as I am descending. I also descend feet first.
Cheers soon to be heavier Ears,
There can be only one,
The Gasman

 

[Groundhog246]

An article I read recently suggested raising both hands up over the head, along with a complete exhalation and be relaxed, to initiate a dive (your gonna have one up on the BC hose anyway). They claimed that position would reduce your buoyancy due to muscle action in the upper body compressing your chest and your arms out of the water add some initial momentum.

Haven't spent a whole lot of time on it since reading it (it's cold up here just now). But was Adjusting weights for new semi-dry in a pool 2 weeks ago and it seemed to help. Of course, I do the first 10 to 15 feet very slowly anyway, or I can't equalize.

Kent

 

[Fetch]

Descend in a horizontal attitude. Purging most of the air from your drysuit before descent would help as well. Don't be in a huge hurry to get down, anyway, go easy on your ears and avoid barotrauma. Once you get 5' down, if you're horizontal you can tilt head down a bit and kick, to get additional speed. I wouldn't really recommend it, unless your buddy decided to leave you.

Horizontal descent at a reasonable rate also prevents landing on the bottom - once I started watching my attitude during descent, keeping my wing inflated enough not to crash on the bottom became markedly easier.

jeff

 

[builderbloke]

ask the skipper if you can "drop the anchor" you may find problems with burst ear drums but youll get the most bottom time

or try adding anouther kilo or two to your belt