Buoyancy question how do you maintain a sitting hover?

[Doc Harry]

How do you do a sitting hover?
Do this:

 

[FishWatcher747]

MichaelMC said "That BC does not seem to offer many options for lead higher up, making a neutral weight distribution more difficult. The one tank band is not very high above the waist. Does the BC allow using a second tank strap higher up? If not, you could put a cam band around the tank near the top and add trim pockets with lead to that band, without any connection to the BC. Or an ankle weight to the tank neck."

So my Aqualung proHD jacket BCD does not allow a second tank strap higher up. Assuming staying with the same BC my options appear to be raising the tank not to raise the COB but to make room higher up for a second cam with trim pockets not attached to BC or throw on an ankle weight around the cylinder neck.

The advantage of the second cam band with trim pockets seems to be I can get 12 pounds of weight (2 three pounders on each side if they are thin three pounders, or 10 pounds, a 2 and 3 if the 3 is fat) whereas an ankle weight is limited to like 3 pounds. Also the ankle weight is soft weight and I don't want to fly with it and not sure how easy it is to rent soft weight.

Is this reasoning correct?

 

[FishWatcher747]

I raised the tank on my BC as far as the strap that goes around the neck of the cylinder will allow. I measured the distance up from the current tankband weight pockets and looks like the proposed additional tank band would put the weights 9 inches above current trim pockets, more toward lower shoulder height.

Is there a way to put a small strap from the BC to this new unattached cam band as a tether so it doesn't slip off? Or if it does slip off it will not be lost and create a safety hazard by unexpected buoyancy? Also do not want to create an entanglement hazard.

 

[Colliam7]

A few thoughts about optimal weighting:

1. Optimal weight is both the optimal amount of weight, AND the optimal distribution of that weight. Much of the commentary you have received has addressed the importance of distribution, and I sense from your responses that you are 'getting it'. That is an important step in development as a diver. I wish I had been a SB user when I was a new diver.

2. Your weight system includes not only your actual lead but your cylinder, your BCD, your regulator, even your fins - IOW, a number of elements in your 'rig' besides the lead itself.

3. There are quite a few ways to move weight 'up', if you are foot-low in the water.

a. Trim pockets have been mentioned. If you have a single cam band BCD, the amount of movement is going to be a bit constrained. But, weight in pockets on the cam band is still 'higher' than weioght on a belt, or in integrated pockets.
b. Pete (The Chairman) showed a picture of ankle weights. A number of divers clip one or two ankle weights around the neck of the cylinder. It may not have tremendous visual appeal, but it works. Yes, that weight is non-ditcheable, but it is usually small in comparison to your primary weight. I frequently put ankle weights on the cylinder necks of students (OW, even AOW) to help then overcome the '45'er' position - swimming along with your body in a head-up, 45 degree angle.
c. Your cylinder is part of the weight system, and a number of us find that using a negativelty buoyant steel cylinder is preferable to aluminum. That often allows us to move weight off our waist (either on a belt on in integrated weight pockets) and shift it 'upward'. You can also shift the cylinder upward, as you have been considering. One limitation I have found with that approach is the position of the valve and first stage. The higher the cylimnder goes, the more likely it is to put the first stage right behind your head, which may be uncomfortable (it is for me).
d. Most fabric BCDs are 'floaty' - postively buoyant, which means that even without air in the bladder the BCD is positively buoyant and 'pulls' your upper body up a bit. To address that, it is often recommended to i) strip as much padding off the BCD as possible (e.g. lumbar pads, and shoulder pads, which may feel good when you try the BCD on in the dive shop, but are really unnecessary for most diving), or ii) move to a fabric BCD that is close to / is neutrally buoyant, or to a metal plate (e.g. stainless steel backplate which positions weight exactly wher most divers find it does the most good - immediately adjacent to the divers center of lift - the thorax.
e. Less common, but nonetheless useful, are approaches that involve using a regulator with a relatively heavy first stage. I personally dive with Apeks first stages - they are a bit heavier than many / most. The difference is not huge, but every little bit of movement of weight toward the head helps.

As to your recent question:

So my Aqualung proHD jacket BCD does not allow a second tank strap higher up. Assuming staying with the same BC my options appear to be raising the tank not to raise the COB but to make room higher up for a second cam with trim pockets not attached to BC or throw on an ankle weight around the cylinder neck. . . .Is there a way to put a small strap from the BC to this new unattached cam band as a tether so it doesn't slip off?

You do not need a tether. You can put a cam band, with a couple of trim pockets on it, on your cyliner near the top (i.e. above the BCD cam band), and lock it down and it is not going anywhere. And, that extra / added cam band is a reasonable approach to try. By the way, the cam band is part of your weight 'system' as well, so use a cam band with a stainless steel buckle rather than a 'plastic' one.

I suspect you may end up trying multiple approaches, before settling on one that works FOR YOU. For me, a HP 100 steel cylinder, an Apeks regulator first stage, a steel backplate/wing BCD, and a small amount of weight on a rubber weight belt work great. That doesn't mean it will be best for you, only that it is one of a number of approaches to think about.

 

[MichaelMc]

Putting 12 pounds on a top cam-band is likely far more than you need. Six would likely go a long way to getting to a balanced weight distribution. The further the weight is from your center of displacement/buoyancy the more impact it has on your balance. It is just like a schoolyard see-saw.

I'm not sure you want the single tank band securing the tank to be way down on the tank. Your photo is about as far up as I would push the tank, with just a fairly low camband, or walking around on land will cause the tank to want to tip over.

You could run a loop of line under the added camband and through the small tank neck strap on that BC, but tightening down the strap should be sufficient. Your BC seems to have a light tank neck strap, that itself would prevent a slipping but still closed camband from going far.

As Colliam7 says, you seem to be on the right path.

 

[jonhall]

How do you do a sitting hover?

I thought about this just today (you beat me to it) but instead of "how", I was thinking "when". When you are in the middle of 1000's of swirling jacks (like your pics) and the DM thinks (or thought in my case) you want to spend 40 minutes of your dive staying in one place!

 

[Celt]

If it’s something you’d really like then get negative fins. Then think air rises and lead sinks so put the weight below the bubble.

 

[FishWatcher747]

This discussion begs the question, why did I buy a medium priced scuba package from a major manufacturer (Aqualung proHD BC) that is not able to be weight balanced right out of the box? If many divers are 45 degree divers, why not change the engineering so they are neutral?

Is it like a sailboat is designed with what they call weather helm? Which means if you let go of the wheel the balance of the sails will round the boat up into the wind as opposed to a dangerous turn to downwind called a jibe.

Is there a fear that if beginners were head heavy that this would be dangerous?

 

[MichaelMc]

This discussion begs the question, why did I buy a medium priced scuba package from a major manufacturer (Aqualung proHD BC) that is not able to be weight balanced right out of the box? If many divers are 45 degree divers, why not change the engineering so they are neutral?

A very excellent question on why BCs are made that can not be readily weight balanced. Cheap 'you can breath underwater (standing up)' comes to mind.

Is there a fear that if beginners were head heavy that this would be dangerous?

I think more that fewer straps are cheaper and smooth wide shoulders look and feel nicer in the store so are easier to sell.

Sorry that you and others wound up with them.

There is also a history of not having BCs back in the darker ages, so diving did not have the freedom to be as calm (not kicking) and in any orientation desired (head up, head down, level) as it does now, so instruction (and thus gear) has not all caught up.

Also 'just put the weight on the belt/hip' is an easy (half-ass) solution to taking care of buoyancy. But, as you've learned, not a balanced weight distribution.

Head down is an awkward feeling as we are not accustomed to it. But it is not dangerous. Diving with head heavy weight distribution is more annoying than with feet heavy weight distribution. Our legs kick in front of us more easily than they do behind our back, so kicking ourselves level is easier with feet heavy than with head heavy.
Super head heavy would be more dangerous on the surface, in that head out of water is rather preferable to head underwater and feet out. But the air shift in the BC would likely help keep you head up feet down.

 

[Colliam7]

This discussion begs the question, why did I buy a medium priced scuba package from a major manufacturer (Aqualung proHD BC) that is not able to be weight balanced right out of the box? If many divers are 45 degree divers, why not change the engineering so they are neutral?

Good question! I will offer MY perspective, which may or may not agree with all. But, first, two caveats - 1) I tell students, and interested divers, that the gear doesn't make the diver, rather the diver makes the gear do what s/he wants it to do. You are asking some good questions, and hopefully learning ways to 'detail' your rig to achieve the kind of buoyancy and trim that you want; 2) in diving, as in most recreational pursuits, the more we develop, and learn and grow, the more likely it is for us to form clearer and more refined opinions about what we want to achieve and what kind of equipment we want to use to reach that goal.

In reality, not all divers are interested in the technology, and what it might help them accomplish. Many buy gear that is easy to buy (e.g. a 'package', rather than individual components), they buy gear that looks good, and smells good, and feels good in the dive shop when they try it on. And, manufacturers are happy to make such gear, and dive shops are happy to sell it. That behavior is not restricted to scuba. That is how many people buy automobiles - they aren't interested as much in the engineering as they are the style. I am not criticizing, that is just the way things are.

From my perspective dive equipment manufacturers - many, but not all - have come a long way. Ten years ago, trim pockets on BCDs were uncommon. Ten years ago, the range of options in BCDs was considerably more limited. But, for the industry to adapt, to make these changes, there needed to be a customer demand. Fortunately, divers - many, but not all - have come a long way, as well. You are a good example, based on the questions that you are asking. As divers progress, they will ask for improvements in gear, that will allow them to more easily achieve good trim, good buoyancy control. For that to happen, dive instruction also had to change. You will see a lot more discussion now on SB, from multiple instructors, about techniques for achieving good buoyancy and trim, than you would have 10 years ago. And, for that transition to occur, there needed to be changes in the philosophies of training agencies. Last, but not least, dive shops - many, but certainly not all - have had to come a long way, from selling primarily high margin / mediocre performance gear as the primary focus, to stocking and providing gear that actually facilitates diver development. All of these changes have been gradual, all of them are still a 'work in progress'. And, the degree to which manufacturers, and Instructors, and training agencies, and dive shops have come along is variable.

Is there a fear that if beginners were head heavy that this would be dangerous?

I don't have any evidence to suggest that was a concern.