Oxycheq vs Golem vs DSS

[hobodiver]

Yes it does, and it's a key reason why I don't like having all my ballast on my rig in cold water.

If you add all 16 lbs of lead to your rig you will need a larger wing. If you keep ~8 lbs in a belt you can use a 26. With 8 in a belt your rig is about -20 lbs.

Add 8 lbs more to the rig and now it's -28 lbs. That makes a 26 too small and a 30 barely enough.

I suggest using a belt. A 8 lbs weight belt is no big deal.

Tobin

Why does it matter where the weight is located? His overall buoyancy doesn't change depending on where the weight is located. That's kind of like saying you're heavier on a scale if you put a 5lb weight in your pocket than if you hold it in your hand.

 

[John_B]

Why does it matter where the weight is located? His overall buoyancy doesn't change depending on where the weight is located. That's kind of like saying you're heavier on a scale if you put a 5lb weight in your pocket than if you hold it in your hand.

It doesn't matter where it is located, it matters whether or not its ditchable.

 

[hobodiver]

While I agree it's a foolish to have no ditchable weight, I don't see how it affects wing size, unless you plan on floating your BP/W without yourself attached to it. To quote:

With a Exposure Suit that's +22 and a Rig that' about -20 lbs you could use a smaller wing. A 26-30 lbs capacity wing would be a reasonable choice.

Even if one assume the exposure suit lost all buoyancy, it would seem a 21lb wing would technically be adequate.

Edit: Note that I am not suggesting the original poster should get a 21lb wing. Just using this as an example based upon someone else's figures.

 

[Nemrod]

Just recently I made a dive in a quarry I had not been in before. It was deep, dark, cold and it was known that there were numerous tunnels. I did not want to accidently enter a tunnel so I had two powerful lights, two reels, medium cave and a jump reel, and a spool and sausage, 30 cf pony as well. I had intended to make the dive with an aluminum 80 but at the last minute due to a damaged valve switched to a pumped steel 85. I did not bother to correct my weight belt etc. The result was that while my 30 pound Mch V handled the job I cannot say there was much left over. Had I not been overweighted, had I dumped some weight from my belt since I had the more negative steel, I would have been in the pink but as it was I had enough, but no more. Perhaps if you intend large steel tanks and other equipment a 40 Mach V would be ideal.

N

 

[John_B]

While I agree it's a foolish to have no ditchable weight, I don't see how it affects wing size, unless you plan on floating your BP/W without yourself attached to it.

Back to the previous quote, I think Tobin was saying if all that weight was not ditchable the OP would need a wing with more lift. OTOH, if part of the weight was on a weight belt which would make it ditchable, then a wing with less lift is possible to use while still being safe.

BTW, I didn't say its foolish to have no ditchable weight, but it could be in certain circumstances.

 

[cool_hardware52]

Why does it matter where the weight is located? His overall buoyancy doesn't change depending on where the weight is located. That's kind of like saying you're heavier on a scale if you put a 5lb weight in your pocket than if you hold it in your hand.

You simply could not be more wrong.

A bc needs to be able to meet two criteria; float your rig at the surface with a full tank, and compensate for the maximum possible change in buoyancy of your exposure suit.

Look carefully at the first criteria. FLOAT YOUR RIG. Anything attached to the rig like say EXTRA BALLAST, will be an added burden for the wing to support if you and your BUOYANT exposure suit are no longer IN THE RIG.

If on the other hand the added ballast is not attached to the rig, but is worn on the divers person, i.e. in a weight belt, the wing will not need to support this portion of the ballast when the diver ditches the rig.

The weight belt stays on the diver and is supported by the buoyant exposure suit.

I'd provide another example, but apparently my first attempt was of no use to you.

Tobin

 

[cool_hardware52]

Back to the previous quote, I think Tobin was saying if all that weight was not ditchable the OP would need a wing with more lift. OTOH, if part of the weight was on a weight belt which would make it ditchable, then a wing with less lift is possible to use while still being safe.

BTW, I didn't say its foolish to have no ditchable weight, but it could be in certain circumstances.

It has nothing to do with whether or not the ballast is ditchable.

Ditchable vs non ditchable is a different debate.

A wing needs to be able to; float the rig at the surface without the diver and his buoyant exposure suit in it, and it needs to be able to compensate for the maximum change in buoyancy of the diver's exposure suit.

These two criteria are not additive. If the diver is wearing, on his person some of the required ballast, for example in a weight belt, this portion of the ballast will not need to be supported by the wing if the diver ditches his rig.

When he doffs his rig, he and his buoyant exposure suit is no long in the rig. Neither is the ballast worn on the diver.

Keep in mind why we need ballast, to offset the buoyancy of our exposure suits.

Tobin

 

[texdiveguy]

I would go with a Zeagle.

 

[cool_hardware52]

Just recently I made a dive in a quarry I had not been in before. It was deep, dark, cold and it was known that there were numerous tunnels. I did not want to accidently enter a tunnel so I had two powerful lights, two reels, medium cave and a jump reel, and a spool and sausage, 30 cf pony as well. I had intended to make the dive with an aluminum 80 but at the last minute due to a damaged valve switched to a pumped steel 85. I did not bother to correct my weight belt etc. The result was that while my 30 pound Mch V handled the job I cannot say there was much left over. Had I not been overweighted, had I dumped some weight from my belt since I had the more negative steel, I would have been in the pink but as it was I had enough, but no more. Perhaps if you intend large steel tanks and other equipment a 40 Mach V would be ideal.

N

Solving the over weighting problem is the answer, not a bigger wing.

Larger wings should not be used to "cure" an overweighted diver.

Over weight a diver, add a larger wing, and what happens if there is a problem with the wing? The diver is in more trouble than if he was properly weighted to begin with.

Tobin

 

[hobodiver]

You simply could not be more wrong.

A bc needs to be able to meet two criteria; float your rig at the surface with a full tank, and compensate for the maximum possible change in buoyancy of your exposure suit.

Look carefully at the first criteria. FLOAT YOUR RIG. Anything attached to the rig like say EXTRA BALLAST, will be an added burden for the wing to support if you and your BUOYANT exposure suit are no longer IN THE RIG.

If on the other hand the added ballast is not attached to the rig, but is worn on the divers person, i.e. in a weight belt, the wing will not need to support this portion of the ballast when the diver ditches the rig.

The weight belt stays on the diver and is supported by the buoyant exposure suit.

I'd provide another example, but apparently my first attempt was of no use to you.

Tobin

Well, that was kind of my question I guess. Why would your rig need to float if you are no longer in it? I suppose if you plan on taking it off after you reach the surface, but it seems to me that the primary purpose of the wing is to get ME to the surface. But I do see your point that it's probably a good idea for the rig to float by itself as well.

Edit: BTW, I do find this very helpful, as I've been thinking of moving to a smaller wing, but now I'm going to have to rethink weather that's necessary/wise.