"Gold Standard" weight check

[Smache]

“Center of air?” “Center of gas”?

Why make up terms?

Is there an existing term for the center of mass of the gas in a cylinder, not the metal of the cylinder itself?

 

[lostsheep]

Is there an existing term for the center of mass of the gas in a cylinder, not the metal of the cylinder itself?

Yes, it’s called the center of mass

 

[MB NZ]

• The diver should have just enough weight to be neutrally buoyant with empty tanks and an empty wing.

Would anyone disagree?

 

[KDAD]

• The diver should have just enough weight to be neutrally buoyant with empty tanks and an empty wing.

Would anyone disagree?

I think it should read:

The diver should have just enough weight to be neutrally buoyant with near empty tanks and an empty wing when at safety stop depth.

 

[johndiver999]

No the diver needs enough lead to control buoyancy while underwater. That means at a depth of one foot not 15. Also if the diver is going to deploy and smb from depth. They need additional lead to keep the end of the smb submerged and the remainder vertical. This obsessive compulsion to chase minimum lead/ballast is often of little practical value.

 

[inquis]

The center of mass is usually understood to be the that of the entire system. The article wants to position the wing to align with the center of mass of the gas alone. You might wish to emphasize that.

You're also neglecting discussion of buoyancy loss due to wetsuit compression and that the wing needs to compensate for that as well. If you align the wing to the gas mass, it may not be aligned with the wetsuit center of buoyancy loss. Since this loss can be much larger than the gas weight, it may be beneficial to shift the wing away from the gas center of mass in such cases.

 

[Norwegian Cave Diver]

We should also mention - doing a SS/Deco stop when horizontal vs vertical.
I prefer to do a SS/Deco stop horizontal. It does a couple things... Allows me to be less streamlined vertically and therefore hold my stop more easily and also allows the minute bubbles in my bloodstream to distribute evenly throughout out my body as I off gas.
Vertically causes the diver to be more streamlined and therefore harder to hold the stop and the minute bubbles will rise to the head/brain.

 

[wetb4igetinthewater]

Also if the diver is going to deploy and smb from depth. They need additional lead to keep the end of the smb submerged and the remainder vertical.

so let me get this straight. Diver whips out their DSMB, finning to compensate for the additional lift of their DSMB when inflated. Once they release, then they add enough gas to be neutral?!?

Or they could just orally inflate their DSMB from a sufficient depth, hold their breath momentarily, until they release their DSMB to they maintain neutral buoyancy throughout the whole process.

 

[Smache]

The center of mass is usually understood to be the that of the entire system. The article wants to position the wing to align with the center of mass of the gas alone. You might wish to emphasize that.

You're also neglecting discussion of buoyancy loss due to wetsuit compression and that the wing needs to compensate for that as well. If you align the wing to the gas mass, it may not be aligned with the wetsuit center of buoyancy loss. Since this loss can be much larger than the gas weight, it may be beneficial to shift the wing away from the gas center of mass in such cases.

That's a good point, especially for thick wetsuits.

Almost all of my diving has been in drysuits. How much does the buoyancy of a thick wetsuit change at depth? Obviously depends on the wetsuit and the depth, but ballpark?

 

[johndiver999]

Can be around 15-20 lbs