Not Enough Weight?

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ouichef

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Location
Sacramento California
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Hi guys! I'm not sure, but I think that I'm not wearing enough weight. I've only been a couple times and starting to "feel" things better and have no problems with most things (so far) but I think better weighting will really help me. I do understand that buoyancy comes with practice and can be difficult but I'm spending a lot of time and effort just trying to stay neutral. I'm 6'6" and 263 (at the times of diving) now after a little work I'm 253 yeah! I've been weighted about 16-18# (7-8k) I descend, most of it is 30-60ft, and when I start if I get within 3ft of the bottom I sink like a rock OR I start ascending. The dive master told me, each time, to let air out of the BCD, guess what? there isn't any, that's right I start floating with a deflated BCD. If I give it shot I going up fast. I would think you always need at a little air in your BCD and that helps compensate for the weights, not the other way around. I don't know, I could be totally off but that's why I'm asking the question.
 
What wetsuit / drysuit are you wearing (I didn't see mention of this in your post)? Fresh or Salt water? Both have a HUGE impact in your weight requirements.

Jim
 
when I start if I get within 3ft of the bottom I sink like a rock OR I start ascending.
This is all very puzzling, and I would love to see this in person. To be honest, much of this is not making sense.
  1. If you sink like a rock, you are overweighted. Period. If you are really properly weighted with no air (or nearly no air) in the BCD, you cannot sink like a rock.
  2. Generally, if you have enough weight to get down to the bottom, you have enough weight for the dive, although the loss of the weight of the air in the tank can cause some trouble at he end of the dive.
  3. If you are overweighted, you can also rise rapidly because the extra air needed to compensate for the weight reacts to the changes in depth. You say there is no air in the BCD, though, so that makes no sense.
  4. You do not mention the wet suit you are wearing. If it is a thick one, it will compress at depth and make you feel suddenly overweighted.

My guess is that you do have air in the BCD but do not know it. How do you know that there is no air in the BCD? Is it because nothing comes out when you vent? If so, that may be the problem. Air wants to go up. If the vent through which you are trying to release the air is not at the highest point, the air will not go out. I see a lot of new divers swimming along while holding their inflator hoses down below them and trying to dump air out of them. That will not work. If you are going to use the inflator hose to dump air, you need to hold it high and make sure that shoulder is also high.
 
Could it have anything to do with how op's breathing at depth? Like, unconsciously holding a breath while focusing on getting neutral then starts rising? On the flip side, letting out a big exhale and sinking a couple of feet?
 
Breathings no problem, used to controlling it from years of Judo and BJJ.
I do hold it over my head when doing an air dump, so I'm pretty sure it's empty.
I don't think I'm explaining it very well either.
Just a shorty suit in tropical waters.
I did add a weight to the tank and it seemed to help with my trim.
IDK, maybe just full of ÷=%
 
I've been weighted about 16-18# (7-8k)

Just a shorty suit in tropical waters.

Just for reference, I am 6-0 and about 220, and if I were diving a shorty in tropical waters, I would use 4-6 pounds of lead.

We are all different people with different weighting needs based upon body composition, but if I were to work with you as your instructor, my initial assumption would be that you are diving with too much weight.
 
I am also puzzled. The deeper you go the "easier' buoyancy is because the pressure difference gets less and less as you descend. I assume you've done a proper weight check at the surface with an instructor. If you gradually sink upon exhaling you're close enough to perfect. Then there should be no sinking like a stone near the bottom. I doubt breathing has anything to do with it because of what you said, plus there is always a "delay" when you purposely inhale or exhale a lot--so no sudden sinking. What John said about venting air and maybe too much weight is all I can think of.
 
When you're venting by lifting the corrugated hose over your head are you horizontal or vertical? If you're in a horizontal position try using one of your kidney dumps. When doing this slightly raise your bum and lower your head so the air in your bcd rises to the area of your bladder closest to the kidney valve. Always remember that the air in your bcd will always travel to the highest point possible.

Sinking like a rock can make sense as you get deeper because your wetsuit will compress making you more negatively buoyant. Corking up to surface could make sense but only as the air in your bcd expands during an ascent.

In the first scenario you may be overweighted. You can compensate this by adding small amounts of air into your bcd until you feel neutral with a half lung full of breath. In the second scenario, I think you may just need to work on your venting techniques.

I have a hard time believing you are under weighted if you are able to get to the bottom in the first place considering your experience level.
 
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Chef you said "when I start if I get within 3ft of the bottom I sink like a rock OR I start ascending." I assume you have the same weight both times right? What is changing, what can change? New divers don't typically breath smoothly one time you just exhaled deeply and down you go. Next time you breath from the top of your lungs holding a lot of air in you lungs up you go, and if you don't exhale strongly you might surface.

I am not implying that your weight is correct, but if you are not adding air to you BCD what can make you go up after descending to 57'..

How are your SS (Safety Stops) at the end of dive in 15-20 feet for 3 minutes? Can you hold them level? Try exhaling deeply at the SS what happens? Try to inhale deeply at the SS what happens? Just some thoughts.
 
Most newbies tend to be overweighted. I certainly was back in the day. I find it highly unlikely that you need more weight especially since you sink like a rock towards the bottom.

As @boulderjohn noted, you probably have air in your bcd that you are unaware of. It's not just what you're holding over your head, but also how your bcd is positioned. For example: It took me some time when I was new to figure out that if I had my head down with my fins above me that air was actually in the bottom of my jacket & I needed to use the bottom dump valve in my bcd to release it.

Even though you may think your breathing is ideal, it's still a different skill to learn in the underwater world. I took many years of yoga & karate. I found I was breathing underwater too deeply like I would in classes on land & these deep breaths would make me wildly rise & fall underwater. As @Kevo88 & @gfaith noted, the same thing may also be happening to you.

You are also probably just struggling with buoyancy as all of us do at first. To figure out if you're weighted well or not, you need to do a proper buoyancy check at the water surface. You may also want to take a buoyancy course or hire an instructor to work with you one-on-one re: buoyancy. I wish I had as it would have drastically improved my diving very quickly.

Congrats on the weight loss!
 

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