Buoyancy question?

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Callo21

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Location
Birmingham, AL
# of dives
25 - 49
I am a fairly new diver, and to be honest I have never checked my weight at the surface like I was supposed to. But, I realized that I sank way to fast. So this weekend I went up to the lake to do some diving, and I thought that I would take this time to set my weights in freshwater. I got in the water emptied my bc and held my breathe and started the process. I started out with 25lbs of weight in my jacket. (I weigh 290 lbs). I might need this much for saltwater, that's why I have so much. I have not been in the ocean yet. Anyway, by the time I got done, I ended up with 5lbs in my vest, and really I still sank a little. So I went ahead and dove with 5 lbs of weight, and didn't have a problem with staying down, even at the end of my dive. I think this is really wierd. So, I am asking what I might have done wrong. Or does this seem right. I might need to list my gear I was wearing.

Neosport 3mm 2 piece suit
100 HP Steel tank
Oceanic probe BC
Small flashlight
Spool (for unexpected emergency)

Thanks for reading this post.
 
The steel tank will definitely help to keep weight out of your pockets. Depending on what brand it is it may still be negative or neutral at the end of your dive or even just slightly positive.

I can dive with a 5MM, gloves, beanie and zero weight with a Faber HP 117. I need about 4 lbs when I dive with the same gear and a HP 80
 
The steel tank will definitely help to keep weight out of your pockets. Depending on what brand it is it may still be negative or neutral at the end of your dive or even just slightly positive.

I can dive with a 5MM, gloves, beanie and zero weight with a Faber HP 117. I need about 4 lbs when I dive with the same gear and a HP 80

I weight 290lbs. It doesn't make sense, or does it?
 
it also raised the question, what if I ever need to dump my weights? I don't have much to dump?
 
I weight 290lbs. It doesn't make sense, or does it?

depends on your body composition among other things. I know a male diver who is basically solid muscle who dives with no weights no matter what type of gear he is in. I have also ran across a very petite woman with no body fat who needed weights in a pool to stay down and she was not wearing a wetsuit? :confused:
 
It depends on what that 290 pounds is made up of.

If you have lots of muscle and bone, then you won't need as much lead as you would if a lot of the 290 pounds is fat.

Most people have just a few pounds of positive buoyancy in fresh water.

The easy test is to go into a pool wearing just a bathing suit and see if you can sink by just exhaling strongly. If you don't sink, then find out how much lead it takes to sink you.

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Not all HP100 tanks have the same buoyancy, but both the 3500psi and the newer 3442psi PST tanks are about 1 pound negative when empty and 8-1/2 pounds negative when full. You need to set up your weighting for when the tank is near empty.

Dumping weight is something done on the surface if you need to stay there for an extended period. Obviously the worst case is with a full tank. If you can easily stay on the surface at the beginning of a dive, then you are fine -- if you are truly properly weighted, then 5 pounds of ditchable weight should be enough.
 
You didn't do anything wrong, and As long as at the end of your dive you can Remain at your saftey stop with 500 psi in your tank than your good, just remember your going to need more weight with an AL tank. you'll also need about 3-4% more weight for Saltwater.
 
You didn't do anything wrong, and As long as at the end of your dive you can Remain at your saftey stop with 500 psi in your tank than your good, just remember your going to need more weight with an AL tank. you'll also need about 3-4% more weight for Saltwater.
that's exactly what I ended my dive with.
 
I wouldn't exactly say I was all muscle by any means. But, I am young and work at pretty hard job, lifting a lot of heavy objects. So I imagine I have a pretty good bit of muscle under my fat.
 
I might need to list my gear I was wearing.

Neosport 3mm 2 piece suit
100 HP Steel tank
Oceanic probe BC
Small flashlight
Spool (for unexpected emergency)

Thanks for reading this post.

For what type of emergency do you expect you might need a spool? How would you use it in that case? (I notice you're not carrying anything that could be on the end of the line on said spool.)
 
https://www.shearwater.com/products/peregrine/

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