Why dont I sink?

[SolarStorm]

I just finished my OWD. For some reason I seemed to need more than twice as much weight as anyone else? The instructor put 20 lbs on me in the pool, and was debating on adding another 5, and couldnt figgure out why I needed so much. Im only 5'11" and 185 lbs.

I was in a shorty 3 mm wetsuit and was using and Excursion BCD (we even tried a different BCD on day 2 incase there was some air trapped.)

I had no problem with the fin pivot (with the 20 lbs) or the neutral boancy float.

I am just curious as to why I seemed to need so much more weight than everyone else?

 

[MauiScubaSteve]

Probably need a little more information to answer your question; how about a picture of you in the shorty wetsuit? Did your instructor talk to you about your breathing pattern? Most people do not take a full breath every breath. That would mean exhaling to completely empty and then inhaling to completely full, every time. The only people I have run into with that breathing pattern were a couple of Mount Everest climbers; I refused to certify them until they showed control of their breathing.

Back to most people. A normal breath, or even a normal deep breath, is about two thirds to three quarters of a full breath (IMHO). You can take that normal breath from a full inhalation starting point to one third or one quarter full, you could take it from a fully exhaled start to two thirds or three quarters full or you could be somewhere in between. A person breathing from the empty lung will have less average buoyancy than if they breath from the full lung.

Also, there are way more factors than just height and weight. Some people have light bones and not much muscle mass; others have heavy bones and not much fat. It is not uncommon for two people the same height and weight to need different amounts of lead.

 

[RonFrank]

I've seen a number of different new divers that were doing strange things that prevented them from sinking. More than one diver was kicking when trying to sink. They are generally NOT aware they are doing so. I went UW and witnessed this, but the divers swear they were NOT kicking.. however my observation says otherwise.

Some new divers hold their breath when trying to sink. Holding your breath as a diver is a bad thing. But it is natural for folks to hold their breath when going UW.

With a full AL80, you should sink if properly weighted regardless of if you are holding your breath as properly weighted means about 4 lbs heavy at a minimum to make up for a lower tank volume (500psi +/-) at the end of the dive.

The way I start to ascend is to first float on the surface, and then release the air from my BC. If the air is gone from my BC/drysuit, and I'm not heading south, I then exhale.

I am 5'8" and 190lbs, and I dive with 20lbs weight DRY in Fresh using an AL80. I maybe a couple lbs overweight, but I would think 20lbs in a shortie would be more than enough weight, unless your bones are hollow!

 

[tstormdiver]

To add to that, many beginner divers will subconciously hold their breath when they first submerge. Let's face it, it's part instinct to do that & to a degree some anxiety. You're doing something new & that you're not familiar with. That causes some stress. That stress affects everyone differently. When you hold air in your lungs, it is like trying to take down an inflated ball of sorts. For students that are having a difficult time descending, when I know they have enough weights, I will instruct them to exhale to the point of maybe a little discomfort. If they feel the need to breathe during the descent, I will tell them to take a short breath & to get rid of it as quickly as they can. Beginners will also tend to kick as they descend to balance themselves, this kicking usually stops the descent & even, at times, puts them back on the surface. I try to get them to be still as they descend. If they feel off balance, I will then instruct them to lean ever so slightly forward as the go down, so that they don't feel as if the cylinder is trying to pull them over backwards.

 

[SolarStorm]

My guess is the holding my breath thing. I have never been described as carrying a couple of extra pounds, and do a number of weekend warrior sports. Just more curious than anything, the thread in the other forum of what happens if you loose your weight got me thinking about how floaty I was. I too will swear I wasnt kicking

Thanks

 

[boulderjohn]

My guess is the holding my breath thing. I have never been described as carrying a couple of extra pounds, and do a number of weekend warrior sports. Just more curious than anything, the thread in the other forum of what happens if you loose your weight got me thinking about how floaty I was. I too will swear I wasnt kicking

There has to be something like that, and probably more, going on if you need 20 pounds in a freshwater pool in a 3 mm shorty and are reasonably athletic in build. I think if we add all the different factors mentioned previously together to come up with the greatest weight need, you should not need 20 pounds. In exactly the same situation you describe, it is unusual for me to put more than 10 pounds on a student. From what you describe for yourself, I would probably have started you with 8 pounds, assuming you would be a bit heavy. The second day of class, after you are feeling more comfortable, I would expect to take some weight off you. I have been fooled before, but never by that much.

I am 6-0, 205. In the pool with a 3 mm shorty, I wear 6 pounds. That is because I want to be overweighted in case I need to deal with a student problem under water. (I may need to control an ascent.) I can actually dive in the pool with a 3mm shorty and an AL 80 with no weights at all.

I would really like to be there with you to troubleshoot the situation.

 

[TSandM]

What's YOUR buoyancy like? In other words, do you sink or float in a swimsuit?

I'm 5'4" and 120 lbs, and virtually every instructor I've ever had has been aghast at the amount of weight I carry. They're always sure they can take some off, and they can't (I'm at least smart enough to do a weight check!) But I float like a cork in a swimsuit, too -- no bone density, I think.

But it seems highly likely that there are other factors at play, as people have mentioned. Is there any possibility that you could get in on another pool session and have someone videotape your attempts to descend? That would give you (and us) a lot more information to work with.

NW Grateful Diver taught me a couple of things when I was new: First off, when you start to let the air out of your BC, don't exhale. If you do, by the time your head goes underwater, you will need to inhale again, and you'll float yourself back up. Instead, as you push the button, INHALE, and as your face gets to the water, sharply exhale and hold it. This will cause your descent to continue.

To keep yourself from kicking without being aware of it, try crossing your ankles. This will do two things -- it will hold your feet STILL, and it will present the fins as a resistance to the water, which will tend to tip you into a nice, horizontal position.

Hope that helps!

 

[TEArrington]

One other quick tip - a lot of folks tell you to exhale quickly. For me, that only causes me to inhale just as quickly in response. What works better for me is to slowly exhale as if I am blowing bubbles. Then I slowly sink a little bit and do not feel desperate to inhale fully on the next breathe. Just a little breath in and more blowing bubbles. Once I get down a little bit, I do not descend in a fully vertical position. I'm sure there are folks who will extole the virtues of doing so, but how is descending horizontally different than changing depths on the dive? For me, it's just more comfortable. I'm very careful to be alert to my surroundings in all directions, and I have a nice relaxed descent.

I've dropped more weight with practice on diving, by better managing my breathing, and adjusting the location of my tank and distribution of my trim and intregrated weights. Best of luck to you.

 

[SolarStorm]

I have always found it easy to float in a swim suit. Could never understand how people sink like a rock. I am not really afraid of going under the water, I was a competitive simmer for 6 years, and 18 years ago, I was a lifeguard.

I am going to try going to an open pool session the local shop puts on this weekend and see if I truely am completely exhaling. If so, I think Im going to start drinking more milk

 

[b1gcountry]

I float like a cork in a swimsuit, too -- no bone density, I think.

Its all that Helium you've been breathing!

Tom