Lotsa Weight

[TMHeimer]

DivingD, Thanks for the advice (and taking the time writing a long post). I do know about the dry wetsuit at the dive's start and do breathe normally (no purposely deep breaths, as to even hyperventilate). I can't recall ever feeling heavy on a dive. I'm not prone to shock from any cold water having lived in the sub arctic.
Doby45--I will try what you suggest when I ever have access to a 15' platform.

So, today I was re-arranging weights in my jacket BC--totally unrelated to this thread. I amazingly by mistake left out 4 pounds, so I did the 2 dives at 39 pounds. These are 15-20' dives. Even on the second dive (with 1900 PSI in the AL80), with the suit not dry, I had to scull down in 5-10' to reach the bottom, then grabbed rocks to make staying down easier until I hit 15-20'. I thought I had lost some weights. Explain.

 

[TMHeimer]

Damn--Must be my computer (but it only happens on SB). I click "save" and wait like a minute and get a double post. I apologize if it's my fault.

 

[Banyan]

It went something like this,
"For scuba diving the end goal is to ideally weight yourself so that at the end of your dive when your tank is almost empty [300 to 500 psi] you can ascend to 15 feet and completely empty your BCD bladder and hold a perfect safety stop controlling your depth with your breath control alone. If you can manage to experiment with your ballast combinations to be able to achieve this then you have achieved perfect weighting.
It doesn't matter at that point what your weight characteristics are at the biginning of the dive because the issue is moot, it's at the end of the dive holding your final 15' safety stop is when it matters."
This made perfect sense to me so I experimented and realized I was dragging around about 10 lbs of excess weight that didn't need to be there. It took me about three dives.
From there I knew about what to expect when changing different cylinders and plates etc. because I had a baseline to work from.
It also so happens that I dive in a 7mm wetsuit complete with booties gloves hood etc.
For me to be perfectly weighted doing the afore mentioned method means I have to actually tip forward at the beginning of the dive and swim down. I will float on the surface with an empty wing and a full tank, that's just how it works out. But I can hold my final stop with an empty tank
At 15' with an empty wing so I know I'm right there.
I also think it's safer this way too. I'm a little leary of having so much weight on that all that's keeping me on the surface is my inflated BC. To me that's abusing something that was originally invented to be used only at depth to take the edge off. I think people who use their BC in this manner are button happy elevator divers, part of the new age of training that is even further removed from where scuba started and totally gear dependant.

I normally dive 10 lbs with a 3mm wetsuit and 3mm hood, but was going vacation diving with a skin and no hood. So I started with 8 lbs and had to add air immediately on entry. Every few dives, I'd take off one or two pounds and then wait for my subconscious breathing rhythms to reacclimate to the reduced weight. By 6 lbs, I no longer touched my BC to add air. I eventually found that I could (barely) hold my stop at 400psi with 2 lbs. I tried without weight at all, but was forced to swim downward by 700 psi. I eventually settled on 4 lbs, it apparently being about at the 2/3rds point of my lungs tidal volume, so I could hold the stop easily without even thinking about my breathing. And now I think I may be overweighted in my "home" rig.

Despite watching me carefully determine my proper weighting over many dives, other divers at the resort insisted that they "needed" 14-18 lbs of lead for diving in their swimsuits, and clearly suspected that I was doing something reckless and unsafe by continuously shedding lead.

So I suppose my advice to the OP is to go on a tropical dive vacation.

 

[gfaith]

@Banyan A good rule of thumb is 2 lbs for every mil in a wet suit. Sounds like you dropped 6 lbs from your "home" rig 10 lbs going to 4 lbs in swim suit (makes sense to me).

 

[TMHeimer]

You guys are talking about a "dry" wetsuit. In shallow water. Yeah, know that. Drop pounds from wetsuit before dive---what is that?

 

[AfterDark]

@Banyan A good rule of thumb is 2 lbs for every mil in a wet suit. Sounds like you dropped 6 lbs from your "home" rig 10 lbs going to 4 lbs in swim suit (makes sense to me).

Now here's something I've never heard before, "2lbs for every mil" thinking about my free diving weight in my 3mil that works out about right. A Farmer John 7mil is actually 14mil around the torso so that throws the rule off a bit. Probably need to work out the % of 14mil and extrapolate from there. That RoT goes out the window with my wife who free dives in a 5mil and floats like a cork with 20lbs!

 

[Diving Dubai]

So, today I was re-arranging weights in my jacket BC--totally unrelated to this thread. I amazingly by mistake left out 4 pounds, so I did the 2 dives at 39 pounds. These are 15-20' dives. Even on the second dive (with 1900 PSI in the AL80), with the suit not dry, I had to scull down in 5-10' to reach the bottom, then grabbed rocks to make staying down easier until I hit 15-20'. I thought I had lost some weights. Explain.

@TMHeimer

It's really hard to diagnose over the internet without seeing you. With everything I know and real world experienced, my gut tells me you're carrying too much weight.

If I used a online weight calculator and plug in your details it comes up with 32lbs. These are notoriously liberal with weight, if I plug in my details it suggests 14lbs when in fact I need zero and am 4lbs or so over.

It doesn't help that your dives are in the 1 ATM pressure zone where buoyancy changes with only slight depth changes. I'm inclined to reluctantly accept that you're naturally buoyant which is part of the equation. I'm still not convinced that your Jacket isn't trapping air or your hood or that you are sub consciously breathing from the top half of your lungs all of which are contributory factors.

As you well know if you can hold yourself at 15-20' with 500psi then you're pretty much there.

Since you are diving in shallow water, why don't you lay on the bottom at 15' with no air in your jacket and attempt to rise up 1' or so just by breathing. Don't worry about the tank contents. in and AL 80 the air only weighs about 6lbs - which in this exercise isn't important (you can factor that in roughly later)

This trick is to get you under water and relaxed. Ideally make it so you can easily take weight out or off your rig (preferably from pockets) You just want to be able to hover (not fin pivot) and then see if you can lose weight or not

 

[llvllatrix]

I fall on the other end of the spectrum; all I need is a 2.5lb back plate and in a t-shirt and shorts, I go straight to the bottom. I'm 5'7" weighing about 195lbs. It's a struggle for me to stay afloat on the surface. I suspect there's quite a bit of variability in human buoyancy.

That being said, it's probably worth eliminating any contributing factors before you come to any sort of conclusion. Seeing how much weight you need to free dive, for example, might yield some interesting results. I'm sure it's been mentioned, but I've noticed that jacket style BCs tend to trap air. Venting from the liver dump in a prone position, with the dump pointed up does help. If you can, borrow someone's back plate for a dive.

Out of curiosity, what's the angle of your torso when you're swimming trim? Is your head pointed towards the dirt, perfectly level or angled up towards the surface?

 

[gfaith]

@TMHeimer all I can say is I do not think you should do a 100 foot dive with the 43 lbs of lead and a 7mil Farmer John. We don't know how your weight is distributed but it still sounds like a lot of weight for your described size. I know you don't do deep dives over 30ish feet and that would be all I would recommend. If your old Genesis Phantom with 20 maybe 40 lbs lift will not inflate... coming up from a deep dive would be a lot of work.

 

[wgw04024]

I read page 1 and page 5 honestly. This seems like a TON of weight. Hard to comprehend honestly. I have a bp/w with a steel plate. I'm 6', 205, and was able to get my weight down to 20 lbs in an 8mm aqualung solafx.

Have you ever done a warm dive with a 3mm suit just for kicks?