Adjusting Weights

[joe rock]

That's true but irrelevant, The diver and all of his/her gear are taken as a whole. Any tank can be configured to dive in a stable manner. A diver with a steel tank may need less weight but if under weighted they will still go positive as they breathe the tank down.

I'm as muck of a steel fan as anyone but tank model/material not the root of the original poster problem. http://home.gwi.net/~spectrum/scuba_al80.html

A good weight check and assurance that he can/is really dumping all of his BC air is needed.

Pete

Pete, you're correct. Thanks for clarifying the issue.

JR

 

[cork2win]

It still amazes me how much difficulty divers, especially new divers, have with weights and buoyancy. The certifying agencies seem to be doing a poor job of training.

Having just finished my OW checkout I wanted to say that there is only so much training I think any agency can do. So much of this requires a "feel" for what's right that I don't think any amount of reading or instruction can teach it to you. Regarding the uncontrolled ascent of the original poster, it happened twice to me this weekend and it's hard to reason why it happens when you're a new diver. I know the science but I didn't know (and probably still don't) the feeling of what's happening soon enough to prevent such occurrences. The science of it can be taught to you but only experience can make you realize what it feels like when it's happening or about to happen and only experience can teach you how to react to it before it happens. I don't think anyone can teach you "the feeling".

 

[jbd]

It still amazes me how much difficulty divers, especially new divers, have with weights and buoyancy. The certifying agencies seem to be doing a poor job of training.

I believe you are correct. There seems to be a certain sense of "refusal" to teach something so basic and so germane to diving.

 

[jbd]

Having just finished my OW checkout I wanted to say that there is only so much training I think any agency can do.

This is true but considering how important proper weighting is to diving it would seem the agencies or at the very least the instructors should make sure proper weighting is taught as opposed to the lip service it is given.

So much of this requires a "feel" for what's right that I don't think any amount of reading or instruction can teach it to you.

Correct, the diver must develope a "feel" for what is right. By starting out properly weighted and properly trimmed from the very beginning, the diver will develope the "feel" much quicker. They will also develope actual skill at diving much quicker which will make their early diving experiences more enjoyable.

 

[cork2win]

This is true but considering how important proper weighting is to diving it would seem the agencies or at the very least the instructors should make sure proper weighting is taught as opposed to the lip service it is given.

You have a good point here. My instructor never actually addressed how I should weight myself, he just told me what I should wear and when he thought I should remove weight. I was never really told what to look for to determine what "proper" weighting was or what variables to adjust for. If I hadn't read so much about it here I'd be pretty in the dark about it, not that I'm all-knowing, but I know more than I would have if I'd only been given the information from my instructor.

Correct, the diver must develope a "feel" for what is right. By starting out properly weighted and properly trimmed from the very beginning, the diver will develope the "feel" much quicker. They will also develope actual skill at diving much quicker which will make their early diving experiences more enjoyable.

Agreed. I was lucky that I was fairly competent with trim/buoyancy just by luck (not that I don't have problems, but I do have many moments of "good" buoyancy/trim) but if I hadn't been so lucky I can't imagine struggling all the time with just trying to stay off the bottom or surface. It certainly would make me reconsider the sport. The few bouts of trouble I had with those were enough for me and they weren't all that frequent compared to others I saw and even I had moments where I thought I would just never get it.

It goes back to the never-ending battle of short classes vs long classes and the purpose of each I guess. I think with possibly double the training I had, those items could have been covered very well, but that would have been 40 hours of instruction not including the check-out dives.

 

[jbd]

It goes back to the never-ending battle of short classes vs long classes and the purpose of each I guess. I think with possibly double the training I had, those items could have been covered very well, but that would have been 40 hours of instruction not including the check-out dives.

I think you might be pleasantly surprised that it really doesn't take adding time to the course to get weighting and trim sorted out. For OW my academic/pooltime only runs about 25 hours roughly split 50/50.

 

[cork2win]

I think you might be pleasantly surprised that it really doesn't take adding time to the course to get weighting and trim sorted out. For OW my academic/pooltime only runs about 25 hours roughly split 50/50.

Maybe I should have traveled to Kentucky for my training.

 

[jbd]

That would have been fine, but it sure would have been a long commute. Cost of gasoline would have probably more than doubled the cost of the course

 

[donacheson]

You have a good point here. My instructor never actually addressed how I should weight myself, he just told me what I should wear and when he thought I should remove weight. I was never really told what to look for to determine what "proper" weighting was or what variables to adjust for. If I hadn't read so much about it here I'd be pretty in the dark about it, not that I'm all-knowing, but I know more than I would have if I'd only been given the information from my instructor.
.
.
.

Proper weighting assumes even more importance as the desirability of slower ascent rates, especially in the last 20 feet before surfacing, becomes a more common practice. It is at this point in the dive when a diver and gear weigh the least while the force of bouayncy is greatest; underweighting makes ascent control difficult and potentially exhausting, overweighting simply more difficult.

I've probably said this a dozen times on this board, but a diver with all gear must be at least minimally weighted - neutral just beneath the surface, with a near-empty tank and empty BC, and breathing normally.

Overweighting requires air in the diver's BC to compensate for the excess lead weight and leads to difficulty in dumping air from a BC while trying to control an ascent. 10 pounds of unnecessary lead causes a diver neutral at 10 feet to be 3 pounds positive at the surface. While 3 pounds doesn't sound like a lot and a skilled diver diver knows how to compensate quickly for this with his lungs, it's a substantial push toward the surface for the novice.

 

[spectrum]

a diver with all gear must be at least minimally weighted - neutral just beneath the surface, with a near-empty tank and empty BC, and breathing normally.

donacheson, I agree totally with your post.

Having air in ones BC during a dive is seen as evil by some and to me that misses the point of wearing a Buoyancy Compensator. You need to be in control thoughout the dive and that includes the final ascent. The very facts that one gains buoyancy as air is consumed and the behavior of exposure porotection demand that the very end of the dive is the defining moment for correct weighting. Anytime before that during the dive some amount of BC air volume is probably needed.

Now that's not to say that lung volume control does not have it's place. It's great for roving from depth to depth within a range and for short term control. To suggest that one continue to breathe with near empty lungs for the duration of a safety stop and ascent is way beyond the ability and comfort of most divers.

This summer I had the oportunity to dive in a 2mm shorty and used just a hardpack, cylinder and regulator, no BC Bladder. I got my weight just right and had to run with "full" lungs for the first 800 PSI and then I became truly neutral with nice full breaths. Swim up easilly, swim down easilly or just hang there. It was a great chance to really see what I could do with my lungs and it genuinely changed how I dive. I never considered myself an inflator junkie but following this dive the amount of water in my BC post dive dropped considerably. If anyone has the chance to try such a dive with a mentor I suggest doing so.

When training, gear, configuration and skill come together it all starts to make sense.

Pete