How to estimate the amount of weight with new gear

[AliLuka]

Hello.. do you do a bouncy check before diving?
Maybe today you dive in fresh water and tomorrow you're diving in salty waters.
Without much of calculations, you need to do a bouncy check. Take 2 kg as example and get to the water. Remove all the air from your BCD, keep only half the air in your lungs and don't kick. See where the water level Is. If you're floating this means you need one more kg and repeat. (Positive bouncy)
If sinking this means you need to remove a kg and repeat. (Negative bouncy)
Till you find the water level is at your mask level then you have the neutral bouncy. But how to go down?? Exhale the other half air in your lungs and enjoy your dive.
It's advised to be a little negative not neutral bouncy when diving with aluminum tanks.
Be aware that steel tanks are heavier than aluminium.
Still, doing the bouncy test is the key since you're renting equipment and maybe today you dive with 5 MMS suite and tomorrow it's 7mms
Maybe you use an old 7mms but feels like it's 6 because it's very old.
Just do the test like you do equipment check before diving
Hopefully my answer was simpl

 

[rsingler]

Thanks so much for this post! It answers a few questions that I had about your spreadsheet

Well, it's probably also worth pointing out the reason the tool was created in the first place, which was NOT as a weight calculator.

It's easy to find "errors" in the weight results it gives you (though I'm glad it's turned out well for you). The whole subject is so complex that not having all the correct input data will give a spurious result.

But that was never the real point. What the tool shows so nicely on the Wetsuit tab is that you can simply jettison a significant portion of your weight, should your bcd tear on coral, or should the corrugated hose connection come loose, and you won't rocket to the surface and get bent.

Instead, you can swim up at modest initial effort, and eventually at minimal effort, to a point at which you are neutral in the water, and can prepare your deceleration strategy for a mildly positive final ascent as originally suggested by @johndiver999 in a contentious thread many years ago.

The tool shows the math behind buoyancy, and is a small effort at reducing through education, the tendency toward overweighting so prominent in the training and resort communities.

 

[adventur]

Is there a chart perhaps to know where to begin establishing weight? Begin with 10 percent of your weight and add how much based on how thick your suit is if using one.

 

[rsingler]

' Info - Optimal Buoyancy Computer

 

[rsingler]

The Quick Start download in the bottom of the first post will show you how to get going easily without getting into all the minutia that the tool is capable of.

Just remember to input your wetsuit thickness in actual mm, instead of advertised "thickness". That's one big source of error, since many manufacturers will include a neutrally buoyant inner liner that traps heat, and call their suit a "5mm" when there are only 3mm of neoprene. Look at the edge where the zipper is and measure that.

 

[adventur]

Thank you