Heavy legs and bouyant head suggestions (opposite of earlier post)

[TSandM]

A diver suspended in water and not moving is subject to the laws of physics, which means that static weight distribution will determine the eventual position at rest. The problem, as has been described above, is that the forces the weights exert depends on where they are located, which means body posture has a great deal of influence.

Sometimes the diver with his feet low is heavy below the center of gravity. Sometimes, he's heavy ABOVE the COG, and dealing with it by rearing up, to shorten the lever arm through which the high weight can work. My husband did not believe me about this, and when he switched to doubles, he kept adding weight up high, until I convinced him to get rid of all of it, at which point he realized he could balance in a horizontal position.

What that means, is that we can't really advise you as to how to solve your problem, unless we have either video to help, or some more information. The information is what happens if you get into a good body position -- head up, body flat, legs either straight out behind you or with knees slightly bent -- and get horizontal, and then see where you rotate to. If, from flat body posture and no finning, you rotate feet down, then you need to move weight above your COG to balance. If you head down, you need to move weight in the opposite direction. The position you currently end up in isn't really good information, because various imbalances can result in the same posture.

Moving weight is easy if you have weight to move; the people who have serious problems are the ones diving in very warm water with no exposure protection, who have no lead to reposition. In cooler water (or with poorer cold tolerance) you have the option of moving ballast, which can usually solve the problem.

 

[The Chairman]

When diving with an aluminum tank, weight distribution takes second fiddle to buoyancy distribution. For most aluminum tanks, sliding it forward will make your butt and feet sink. Sliding it back will do the opposite. No, it's not intuitive and it can be damned frustrating that it works counter to what you thought. You have to factor in the floaty butt of the AL80 and the moment arm it creates from the cam strap. It's like a lever pulling up the rear. Increase the length of the lever (slide it down/back) and you increase the effect of the pull up. FWIW, this is yet another reason I like double tanks cam bands. It keeps the lever arms small and manageable.

Steel tanks are the exact opposite because they don't have a floaty butt. You only have to deal with weight distribution and can ignore buoyancy distribution.

 

[DiverRtNY]

Are you saying you're concerned that putting weights on your shoulder straps, which it would appear your BCD would allow very easily, is a safety issue? If so, how so? Also, on the subject of safety, some people will tell you to take that bungee off your bladder because it's a safety issue if you get a puncture. I'm not advocating that, just giving you a head's up.



People will tell you this and that you're just not a good enough diver yet if things don't work for you. And that might be true. However, there is also this thing called physics, which you can dislike, but can't win against. The bottom line is that weight distribution matters (which is why all the suggestions of moving the tank around, moving weight here, there, etc.). Just to be clear, my suggestion isn't to add more weight, it's just to move it to a location that counters your heavy legs. You're diving a floaty BCD, which will exacerbate the issue because the loft on it is all around your upper torso.

I guess my thought on it being a safety issue would be having more accessories on/near front of bcd. With other equipment, such as retractable compass and second stage hoses and BCD inflater hoses, on top of managing diver flags or whatever could be an entanglement issue. But like you said, the bungees on my BCD would also be seen as an issue and having weight trim around tank neck would pose a threat, too. I do appreciate the info and I will give this a thought as to alleviating a neck tank trim issue.

As far as my body habitus goes... I'm 5'9" and weigh 200. Use to weight train and could (past tense) leg press 1300 lbs and throw up some weight so not exactly a fat upper body type. My occupation is a respiratory therapist (hence diverRTny) and my job is about breathing. To get to my point, I have performed many lung function tests on myself, out of curiosity, and I have very large lung capacity compared to the average joe and have a barrel like concave chest . My thought is that this, mucho air space in my breathing tubes, with having muscular legs leads to my more bouyant upper torso. And with the floaty BCD on upper torso doesn't help. Practice and self reflecting on my body positioning through videos and pictures is something I will also focus on and obsessing over something as minor as 1 1/2 lb tank neck weight might be OCDing a bit but that's what I do. My horizontal positioning is effortless with the said weight around the tank neck and maybe I should just tank it with a grain of salt. The more I dive, the more I seem to require less weight... This might adjust itself out as my diving skills improve.
Again... thank everyone for thoughts and suggestions to think outside the box. That's why we/us all have these forums and enjoy utilizing the opportunity. It's interesting to hear how very experienced divers each have their own unique approach to solving/ perfecting their diving and understanding there are many routes to solve/perfect certain skills/flaws. Is there a right way or a wrong? To each their own. When I get some video of myself doing a horizontal trim hold I look forward to hearing others thoughts and recommendations.

 

[The Chairman]

FWIW, I use 4 pounds of weight on my SMS 100 harness shoulder straps. I hope to try the Nomad LTZ while I am here in Cave Country to see if I can get away from that.

 

[DiverRtNY]

FWIW, I use 4 pounds of weight on my SMS 100 harness shoulder straps. I hope to try the Nomad LTZ while I am here in Cave Country to see if I can get away from that.

Off topic NetDoc, but is there a sidemount BCD that can also be used for rear mount that isn't pushing 700$ that you would recommend?

 

[The Chairman]

I don't recommend mixing the two like that. I did in this thread: http://www.scubaboard.com/forums/si...ide-mounting-mods-my-zeagle-express-tech.html However, I find that I don't use that setup for ANYTHING but sidemount. With the advent of the SMS 100, I don't even use it for that much anymore. I think it's time to turn it back into a back mount rig for students. The SMS 100 and I believe the SMS 75 by Hollis can both be used either way but I have yet to utilize that feature. Once I am set up in a rig, I'll tweak it, but I don't like swapping it back and forth from one style to the other. Dive RIte's Nomad LTZ has no such delusions of doing both and that appeals to me. I'll start a thread about it if I get to dive it this weekend.

 

[Kharon]

... You learn to compensate with your body and if you have any experience diving multiple types of gear, you learn to adapt.

Yep. Ever see a fish, and I mean EVER, that was totally motionless in the water? Me neither. They are always finning - tiny fins all over their body - pectorals, dorsals, anals - even if they aren't moving their tail. However, they are in trim - totally. We divers are an extremely poor mimic of those fish. All we can do is attempt to get as close to their weight distribution in order to be able to hover in any position with the minimal arm and leg movement.

---------- Post added October 24th, 2014 at 11:14 AM ----------

Steel tanks are the exact opposite because they don't have a floaty butt. You only have to deal with weight distribution and can ignore buoyancy distribution.

Why my tanks are steel.

 

[Michael Guerrero]

My horizontal positioning is effortless with the said weight around the tank neck

Then I would leave it for now. It's a small amount of weight and you may find that one day you forget it at home or something, and are able to dive just fine without it with more experience. This is the case for many people. Having good trim is way more important than how cool you look .

It's interesting to hear how very experienced divers each have their own unique approach to solving/ perfecting their diving and understanding there are many routes to solve/perfect certain skills/flaws. Is there a right way or a wrong? To each their own. When I get some video of myself doing a horizontal trim hold I look forward to hearing others thoughts and recommendations.

Yup, many ways to skin a cat.

I look forward to watching the video and trying to help further.

 

[Adobo]

My thought is that this, mucho air space in my breathing tubes, with having muscular legs leads to my more bouyant upper torso. And with the floaty BCD on upper torso doesn't help. Practice and self reflecting on my body positioning through videos and pictures is something I will also focus on and obsessing over something as minor as 1 1/2 lb tank neck weight might be OCDing a bit but that's what I do. My horizontal positioning is effortless with the said weight around the tank neck and maybe I should just tank it with a grain of salt. The more I dive, the more I seem to require less weight... This might adjust itself out as my diving skills improve.

I think maybe you misunderstood the context when heard/read people saying that ankle weights are crutches.

Some people use ankle weights around their ankles to compensate for a head heavy, floaty legs issue. Its not uncommon to see with drysuit divers but I have seen even wet suit divers with ankle weights around their ankles.

I personally think that ankle weights used for the above purpose is the wrong way to go. So I can see why others might be saying that ankle weights are a crutch - in this context.

However, everybody with a wetsuit or a drysuit likely uses some ballast. Weather that ballast is in the form of an ankle weight or a bullet weight or a square weight or a v-weight doesn't really matter.

The question for you really is, is there a better way to situate whatever weight you are using? I don't really see anything wrong with having an ankle weigh wrapped around a tank valve as a short term solution. In the long term, it might be better to keep it with the rest of your ditchable weight if it needs to be ditchable. If not, it might better to keep it in an appropriate trim pocket so there is no chance of it inadvertantly falling off or getting caught on something.