Preach on, Brother John!
"Correct Weighting" Identified as #1 Needed Improvement in SCUBA Diving
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@The Chairman - For the record, I agree with your training as you have described it. As I said previously, I am convinced that taking the skills training off the bottom will help. In a pool (which is shallow), a student with way too much weight will not be able to hold a depth station. However, I think it will still likely mask smaller errors. Students will be unlikely to pick up on whether or not they have 2, 3 or maybe even 4 pounds more weight than necessary. If you are sans BC, you will be able to feel it if you are 2 pounds off.
My goal is to be within -+1 pound of ideal. I don't think that skill can be learned without some experience diving without the BC. It's a nice skill to have, and I still think there are useful lessons to be learned from going through the experience of diving sans BC, lessons that could address the deficiency identified by DAN. Like I said, once you have it, the skill doesn't go away, and you can carry that through to the rest of your diving.
My goal is to be within -+1 pound of ideal. I don't think that skill can be learned without some experience diving without the BC. It's a nice skill to have, and I still think there are useful lessons to be learned from going through the experience of diving sans BC, lessons that could address the deficiency identified by DAN. Like I said, once you have it, the skill doesn't go away, and you can carry that through to the rest of your diving.
This OP offers an interesting perspective. And, I have mixed reactions. On one hand, learning to dive without a BCD is a good idea in many ways. It requires a diver to really work on the use of breathing alone for buoyancy compensation. And, that is a good practice. I also agree with what I sense is part of the OP’s concern. I do not believe that – in all cases – OW instructors actively work on optimal weighting – which is a matter both of the total amount of weight, AND the distribution of that weight. Unfortunately, notwithstanding all of the commentary, discussion, agency guidance, etc., there are still some instructors who overweight students, through intention or incompetence. I wish that were not so, but it is. But, it is not accurate to make the broad generalization, that proper weighting ‘is not taught’ – it is. And, I seriously doubt that the problem of some instructors failing to teach it properly would be addressed by having divers, beginning with their initial training, dive without a BCD. The very same instructors would probably overweight them in that configuration as well.
The problem that I see in practice is not that the procedure for performing a proper weight check is not taught. Rather, the problem is that the procedure for performing a proper weight check, like too many other skills learned in OW training, is not practiced again after certification. So, the diver in the case referenced in the DAN publication may have required a considerable amount of weight during OW training – perhaps they were wearing a 5mm farmer john, with a 5mm shorty , and a hood, and gloves, and were using a floaty jacket BCD, and an AL80. (OK, even then 50 lbs is A LOT of weight.) But, perhaps they decided to use the same weight they required with such a configuration in OW training, when they were later diving in warm water, with just a rash guard, and a HP 100.
Where I very much agree with the OP – a weight check is entirely and completely specific for the particular configuration – the BCD, exposure suit, and cylinder. Yes, it is also specific for the regulator, but the amount that item contributes is minimal compared to the other three parameters. So, a competent diver will develop over time a chart of the weight required, for the various combinations of BCD, exposure suit, and cylinders that they may dive. For some, it is always the same. For others, it can vary. I have just such a chart developed over time. I can use the chart to determine what amount of weight I need for a wetsuit, be it 1mm, 3mm, or 5mm, or for one of my two drysuits, with a stainless steel backlplate and wing, or an AL backplate and wing, or for a jacket BCD, or a back-inflate BCD (Zeagle Ranger), using an AL 80, or a HP 100, or a HP 120. That table has taken a while (years) to create. And, it is periodically updated since I usually do weight checks, along with my students, at the beginning of every class I teach.
I do not believe that is is possible, if this procedure was followed and a proper weight check periodically performed, for a diver to be as (apparently) massively overweighted as the diver in the DAN case cited by the OP. The problem is not a matter using a BCD or not - a BCD has value in diving, under certain conditions. The problem is failure of initial instruction AND a failure to maintain skill currency.
The problem that I see in practice is not that the procedure for performing a proper weight check is not taught. Rather, the problem is that the procedure for performing a proper weight check, like too many other skills learned in OW training, is not practiced again after certification. So, the diver in the case referenced in the DAN publication may have required a considerable amount of weight during OW training – perhaps they were wearing a 5mm farmer john, with a 5mm shorty , and a hood, and gloves, and were using a floaty jacket BCD, and an AL80. (OK, even then 50 lbs is A LOT of weight.) But, perhaps they decided to use the same weight they required with such a configuration in OW training, when they were later diving in warm water, with just a rash guard, and a HP 100.
Where I very much agree with the OP – a weight check is entirely and completely specific for the particular configuration – the BCD, exposure suit, and cylinder. Yes, it is also specific for the regulator, but the amount that item contributes is minimal compared to the other three parameters. So, a competent diver will develop over time a chart of the weight required, for the various combinations of BCD, exposure suit, and cylinders that they may dive. For some, it is always the same. For others, it can vary. I have just such a chart developed over time. I can use the chart to determine what amount of weight I need for a wetsuit, be it 1mm, 3mm, or 5mm, or for one of my two drysuits, with a stainless steel backlplate and wing, or an AL backplate and wing, or for a jacket BCD, or a back-inflate BCD (Zeagle Ranger), using an AL 80, or a HP 100, or a HP 120. That table has taken a while (years) to create. And, it is periodically updated since I usually do weight checks, along with my students, at the beginning of every class I teach.
I do not believe that is is possible, if this procedure was followed and a proper weight check periodically performed, for a diver to be as (apparently) massively overweighted as the diver in the DAN case cited by the OP. The problem is not a matter using a BCD or not - a BCD has value in diving, under certain conditions. The problem is failure of initial instruction AND a failure to maintain skill currency.
I certainly don't see a need for this kind of minimalism. I like to see my students to be within 2/3 pounds. Getting them lower than this is actually counter productive. How is that? When I titrate my student's weight, they are super calm, both hands & fins are crossed and they start floating on the surface with an empty bladder. For every inch their head is out of the water, I give them a pound (in two pound increments) until their head is just awash. If they come across as easily excitable, I give them another two pounds for good measure. Why? because excitement often results in breathing on top of the lungs. It becomes physiologically difficult for them to exhale making them a bit more floaty, which adds to their anxiety and makes them even floatier. So the cycle escalates.
So what causes excitement in the new diver? Just about EVERYTHING! Oooooh, look a shark! Ohhhh, a pretty fishy. Ohhhh this surge is making me feel sick. Ohhhhhh, a mermaid! So getting them down to the last ounce can work against you.
Remember the weight pick up where they breathe it neutral? If I start perfectly neutral, I can easily pick up 12 pounds and have gone as high as 18 pounds. Why am I going to worry about 2 to 3 pounds?
In my case, I strive for that 1 pound level of accuracy because when I do, I can leave the BC in the closet. When I don't need the BC, my dives are far more enjoyable, and I do not kick the reef when I dive that way. However, if you stop at getting to within 4 pounds or so of "right", yea, you're going to have problems staying off the bottom without a BC. Getting your weight to -+4 pounds is just not good enough unless you have some other control system to correct the error.
I got dupped recently. I thought I had everything set right. But, when I got in I was too heavy. It turns out that what I thought was a standard AL80 was something called a neutral 80, a tank that is about 4 pounds heavier than a standard 80. I had a weight configuration that wasn't going to work. Fortunately, due to my familiarity with the location, I didn't need to get out and change it. Instead, I just ditched my 4 pound neck weight in a location where I knew I'd be able to retrieve it later and then continued the dive normally. I hadn't encountered a neutral 80 before. Now I know they are out there, and I've added it to my library of variables. It won't surprise me again.
If I had been diving with a BC, I probably would not have noticed that the tank was different. I would have been diving with an extra half gallon of compressible and unstable air in the BC and I would have been fiddling with the controls wondering why I'm having more problems than usual controlling my buoyancy. I'd have had an anomalous dive experience instead of a new data point.
Edit - We should consider that there is a certain human element to all of this. In some cases, it will not matter what someone is taught. Some will never learn to weight themselves to within a pound of accuracy even if they are diving a simple backplate. They will just crawl on the bottom and call that good enough for now. Some will never learn to weight themselves to within 4 pounds accuracy with a BC, and they'll sink to the bottom wearing 50 pounds of ballast. I want to think that if a diver had an initial experience diving with a backplate, they'd be more likely to later get within that 4 pound range, but that may not be the case. Some people just defy explanation.
I got dupped recently. I thought I had everything set right. But, when I got in I was too heavy. It turns out that what I thought was a standard AL80 was something called a neutral 80, a tank that is about 4 pounds heavier than a standard 80. I had a weight configuration that wasn't going to work. Fortunately, due to my familiarity with the location, I didn't need to get out and change it. Instead, I just ditched my 4 pound neck weight in a location where I knew I'd be able to retrieve it later and then continued the dive normally. I hadn't encountered a neutral 80 before. Now I know they are out there, and I've added it to my library of variables. It won't surprise me again.
If I had been diving with a BC, I probably would not have noticed that the tank was different. I would have been diving with an extra half gallon of compressible and unstable air in the BC and I would have been fiddling with the controls wondering why I'm having more problems than usual controlling my buoyancy. I'd have had an anomalous dive experience instead of a new data point.
Edit - We should consider that there is a certain human element to all of this. In some cases, it will not matter what someone is taught. Some will never learn to weight themselves to within a pound of accuracy even if they are diving a simple backplate. They will just crawl on the bottom and call that good enough for now. Some will never learn to weight themselves to within 4 pounds accuracy with a BC, and they'll sink to the bottom wearing 50 pounds of ballast. I want to think that if a diver had an initial experience diving with a backplate, they'd be more likely to later get within that 4 pound range, but that may not be the case. Some people just defy explanation.
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Most of us who teach, see this as a fool's errand: a chasing your tail as it were. Have fun with it all you want, but I won't be suggesting this to my students. Not having a BC on the surface, especially in rough seas, can be fatal. Having buoyancy on the surface is not an option for me and my students. It's like riding a bike without tires. Your running on the bare rims and it ain't pleasant. I'm sure you'll stand out on the boat, but don't expect many of us to be impressed and don't be offended when we defer from being your buddy.
BTW, I'm taking from how you're couching things that you're not an instructor. Please confirm.
I appreciate how weighting can be a contentious topic.
Weighting to be "perfect" would be difficult for me I reckon - my normal wetsuit at home is a 4XL 7mm steamer (required due to height as well as my slowly reducing girth). If I weight correctly at the surface (guessing about 1.5Kg/mm thickness due to the size) and allowing for compression at 20-30m depth to 2-3mm means I am now 6-7.5 Kg overweighted. Kind of hard to cope with that extent of a shift without having some means to compensate for it.
Weighting to be "perfect" would be difficult for me I reckon - my normal wetsuit at home is a 4XL 7mm steamer (required due to height as well as my slowly reducing girth). If I weight correctly at the surface (guessing about 1.5Kg/mm thickness due to the size) and allowing for compression at 20-30m depth to 2-3mm means I am now 6-7.5 Kg overweighted. Kind of hard to cope with that extent of a shift without having some means to compensate for it.
I don't really want to be out on the water in 6 foot seas. There are a lot of situations where diving a minimalist rig is not appropriate. However, there are also a lot of situations where it is appropriate, and those situations happen to coincide with the majority of recreational dives conducted. Minimalist diving can be inexpensive, fun and easy by comparison to the standard way of doing things.
Back in the early '60, my dad was listening to a guy in the barbershop talking about how he was going to build a little airplane that was going to weigh about 200 pounds and fly on 20 HP. My dad, being a pilot, was familiar with how airplanes were built and functioned. He said that it would never work. And indeed, what the guy wanted to make was considered illegal by Congress and the FAA. Obviously, he and others persisted against the grain of the existing Law, because about 2 decades later, Congress conceded and passed FAR Part 103 recognizing and finally legalizing what is now known as the Ultralight aviation movement.
The point of this story is that to break the mold, one must first get out of the mold. If some people were not willing to do things considered wrong by the existing industry, one of the most popular, fun and inexpensive branches of aviation may never have been developed.
At least in diving, I don't need to break any laws of Congress to do what I do. I'm only breaking rules of the established training agencies. With that, I'm sure it is of no surprise that I am not a cawg in the existing machine of training agencies. So, no, I'm not an "instructor" as you would define it. I'm the guy pushing the boundaries of what other divers think is possible and/or safe, and showing by demonstration that it can be possible and/or safe and how to do it.
I develope new gear and new methods that work, but work differently from the established norm, and under the right conditions, work better. There is a strong parallel between what I do and what the ultralight guys of the 60s and 70s were doing before ultralights were officially recognized as a valid form of aviation.
Not everyone wants to dive 40 or 50 meters deep into a cold dark ocean below 2 meter rollers and chop. Most people want to dive 20 meters down in a warm clear ocean when the weather above is nice and the seastate is calm. If those conditions are not present, many people are likely to make this day a kite-boarding day, or a ziplining day, or something else. Not everyone wants to be an all weather diver, and not every pilot wants to fly in all weather conditions.
Unfortunately, the currents don't correlate with nice weather and flat sea conditions, so the ideal equipment will be well suited to deal with the statistical distribution of currents that are likely to happen even when the weather is nice. I have found that minimalist gear is actually better suited to those conditions than the established "normal gear" configurations. This is why I advocate for a method of diving that isn't presently sanctioned by training agencies.
This no BC argument makes no sense to me? As scuba requires a tank on your back that will most likely be around 3 lbs positively buoyant (AL80) at the end of a dive, you need to offset that with sufficient weight to avoid popping to the surface at the end of your dive when you are doing a safety stop. That required weight makes you negatively buoyant at the start of the dive. I can (and do) use breathing techniques to control/change depth but I don't see how I can use breathing to hold a depth if I'm weighted to be negatively buoyant in the early part of the dive (unless I hold my breath which inflate my chest and breath very shallowly which do not seem good ideas)?
So, for me, having a BC (Halcyon Infinity BP/W in my case) is a way to offset that initial negative buoyancy. It also allows you to float comfortably on the surface and relax before you start the dive, allows you to add/remove a smidge of air to better establish neutral buoyancy throughout your dive and float more comfortably on the surface at the end of the dive as well (especially in swells/chop). I know I appreciated it last week in Aruba, where we had 4-6 foot swells and current on the surface (but very nice condition 40-110 feet below).
To me, use of a BC and use of proper amount weight are 2 different concepts. The BC allows me to deal with the required negative buoyancy at the start of a dive. Proper weighting is about being able to descend easily at the start of the dive and offsetting your empty tank a the end of the dive - to do that, I do weight checks at the end of dives to make sure I only carry the least amount of weight needed. As I've dived more, I have dropped considerable weight and now add very little air to the BP/W only as I reach depth to help establish neutral buoyancy and it's then vented/emptied by the time I'm at my safety stop. If I did not have a BC, how would I offset the required initial negative buoyancy on the surface or at depth? Finning? No thanks, I'd rather conserve my air for diving.
Also, I did my initial OW training and PPB in a cold quarry with a full 7 mil wet suit, gloves, hood and AL 80 with 26 lb of weight, but now dive tropical with a rash guard or 3 mil shorty only and AL 80 or AL 100 and am down to 11 lb. I think I can still even even go less and continue to reduce and verify with buoyancy checks at the end each dive. I see proper weighting as something you figure out over time by diving. Once you get is dialed in, you won't need to worry about it again until you change gear or environment.
Am I missing something here?
So, for me, having a BC (Halcyon Infinity BP/W in my case) is a way to offset that initial negative buoyancy. It also allows you to float comfortably on the surface and relax before you start the dive, allows you to add/remove a smidge of air to better establish neutral buoyancy throughout your dive and float more comfortably on the surface at the end of the dive as well (especially in swells/chop). I know I appreciated it last week in Aruba, where we had 4-6 foot swells and current on the surface (but very nice condition 40-110 feet below).
To me, use of a BC and use of proper amount weight are 2 different concepts. The BC allows me to deal with the required negative buoyancy at the start of a dive. Proper weighting is about being able to descend easily at the start of the dive and offsetting your empty tank a the end of the dive - to do that, I do weight checks at the end of dives to make sure I only carry the least amount of weight needed. As I've dived more, I have dropped considerable weight and now add very little air to the BP/W only as I reach depth to help establish neutral buoyancy and it's then vented/emptied by the time I'm at my safety stop. If I did not have a BC, how would I offset the required initial negative buoyancy on the surface or at depth? Finning? No thanks, I'd rather conserve my air for diving.
Also, I did my initial OW training and PPB in a cold quarry with a full 7 mil wet suit, gloves, hood and AL 80 with 26 lb of weight, but now dive tropical with a rash guard or 3 mil shorty only and AL 80 or AL 100 and am down to 11 lb. I think I can still even even go less and continue to reduce and verify with buoyancy checks at the end each dive. I see proper weighting as something you figure out over time by diving. Once you get is dialed in, you won't need to worry about it again until you change gear or environment.
Am I missing something here?
Not exactly. It doesn't matter what tank you use. If you are weighted to be neutral with a near-empty tank, then you will be negative by the amount of gas you're carrying. Whether you're using an AL80 that is floaty when empty or a steel HP80 that is negative when empty, if you are properly weighted, you will start the dive being about 6 pounds negative, as that is the approximate weight of 80 cu-ft of air.
If you are diving with a single HP120, you'll start off about 9 # negative. If you're wearing a 7mm wetsuit, and you dive your HP120 to 130', your suit will compress and you could end up being 20# negative at the bottom, at the start of your dive.
I am in NO way pushing the idea of diving or teaching scuba with no BCD. But, I think REVAN's point is not that you should use no BCD in all conditions (e.g. a steel tank and a 7mm wetsuit). His point was to teach that way in warm water with (I assume) AL80 tanks. In those conditions, the most negative you should be is 6 #, with little or no concern of additional buoyancy loss from suit compression. And, in those conditions, as Pete has already observed, you can compensate for 6# just with your breathing.
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