Ditchable weights or non?

[bubbletrubble]

Originally Posted by ianr33

What I do sometimes do is carry "semi ditchable" weight on the waist strap of my BP/W harness. I just thread a regular weight on the waist strap. To ditch it I would have to undo the buckle and unthread the weight.

@ianr33: Interesting idea. How do you balance the weight on the other side? I'm guessing that you don't put it "behind" the buckle.

[Gombessa]

Originally Posted by bubbletrubble

@ianr33: Interesting idea. How do you balance the weight on the other side? I'm guessing that you don't put it "behind" the buckle.

You don't typically need to actively "balance" small weights like that, but even large weight disparities are naturally balanced by the air distribution in the wing.

[bubbletrubble]

Originally Posted by Gombessa

You don't typically need to actively "balance" small weights like that, but even large weight disparities are naturally balanced by the air distribution in the wing.

I could totally understand a 2 lb. weight not making an appreciable difference. Considering that a can light might also be on the righthand side, how much of a left-vs.-right discrepancy is noticeable? Would a 4 lb. weight feel "unbalanced"? This might make for an interesting experiment on my next dive.

[Gombessa]

Originally Posted by bubbletrubble

I could totally understand a 2 lb. weight not making an appreciable difference. Considering that a can light might also be on the righthand side, how much of a left-vs.-right discrepancy is noticeable? Would a 4 lb. weight feel "unbalanced"? This might make for an interesting experiment on my next dive.

I've dived with 8lb on the right side of a weight belt and 0lb on the left side (extenuating circumstances). You don't feel it at all, because you naturally migrate the air in your wing to the right side to offset the extra weight. You can't see it, but the right side of your wing will puff out more as it takes the load.

This is how divers carry stage and deco bottles all on one side - the wing carries the weight to help you maintain trim.

[bubbletrubble]

Originally Posted by Gombessa

I've dived with 8lb on the right side of a weight belt and 0lb on the left side (extenuating circumstances). You don't feel it at all, because you naturally migrate the air in your wing to the right side to offset the extra weight. You can't see it, but the right side of your wing will puff out more as it takes the load.

This is how divers carry stage and deco bottles all on one side - the wing carries the weight to help you maintain trim.

Hmmm. That's interesting. An 8 lbs. discrepancy from side to side. My gut reaction is to ask what happens when there is minimal air in the wing. I guess this is probably why stage/deco bottles are AL tanks with a buoyancy swing from slightly negative to positive. Since the tanks are slung on the left, I can also see why threading weight onto the right side might help balance things out a little.

Just thinking out loud here, but perhaps with a drysuit, even more of a lateral discrepancy might be compensated for.

[Gombessa]

Originally Posted by bubbletrubble

Hmmm. That's interesting. An 8 lbs. discrepancy from side to side. My gut reaction is to ask what happens when there is minimal air in the wing. I guess this is probably why stage/deco bottles are AL tanks with a buoyancy swing from slightly negative to positive. Since the tanks are slung on the left, I can also see why threading weight onto the right side might help balance things out a little.

Just thinking out loud here, but perhaps with a drysuit, even more of a lateral discrepancy might be compensated for.

On descent I have zero air in the wing for a few seconds while horizontal in the water column. There's absolutely no inclination to flip on my side or turtle. 8lb may sound like a lot, but when firmly secured to your body with a tight weight belt, it's very close to your center of gravity and doesn't affect trim in any noticeable way. If it's not firmly secured (like my second dive that day), you end your dive noticing that the belt has shifted and the weight is hanging below your belly.

[bubbletrubble]

Originally Posted by Gombessa

If it's not firmly secured (like my second dive that day), you end your dive noticing that the belt has shifted and the weight is hanging below your belly.

You know, I just realized that if one adjusted his buckle properly (keeping the buckle end rather short), the weight threaded onto the free end of the waist strap could be placed near the midline -- much like the weight on your loosely adjusted weight belt.

OK. I have to ask. Why were you diving with 8 lbs. on one side of a weight belt?

[Gombessa]

I usually dive 16lb - 2 x 8lb weights. I had a new set of tanks with me that day and thought I was going to be overweighted. Of course, I could have brought extra weights with me, like two 4lb weights. But no, I was way too smart for that.

[Taigin]

So for the purposes of the original question, you guys seem to make an effort to remain as neutrally buoyant as possible if not slightly negative at the beginning of the dive using non-ditchable weights, and use a SMB for emergency buoyancy. Some carry a couple pounds of ditchable weight so that they can slowly ascend to the surface rather than take off like a bat out of hell, or for the purposes of trim.

In some cases you just need the extra weight on the belt to counter excessive positive buoyancy from a thick wet suit. Got it.

I have noticed a couple BP/W systems where you mount pouches to the wing/belt and it can pull out like the jacket/back inflate BC's do. I have not heard anyone say they use those.

PERSONALLY, I will be diving here in Hawaii with a 3 mil wetsuit at most, at the moment, the full setup has 7lbs 13 oz of known neg bouancy (rings, harness, buckle: Unknown) So I guess we will see how that works. I may wait to get a SMB before I use it, Just In Case.

Anything I missed? Suggestions?

Not trying to stop the conversation, just trying to extract and condense some of the pertinent data.

[ianr33]

Originally Posted by bubbletrubble

@ianr33: Interesting idea. How do you balance the weight on the other side? I'm guessing that you don't put it "behind" the buckle.

No need to balance it.It does not cause a problem. I normally dive doubles, suppose it might be different in a single but my guess is not. The weight can also be used to secure a can light if you use one.

Anyone that is concerned about balancing the weights can put one on the left of the waiststrap as well. This will be non ditchable and is a bit of a pain to put on as you need to remove the buckle and left hip d ring first.