Buoyancy and Trim: Are You Game?

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oya

Rebreather Pilot
Scuba Instructor
Messages
490
Reaction score
1,037
Location
Akumal, MX
# of dives
5000 - ∞
A few weeks ago I posted a whole blog thing about how to think about getting trim and buoyancy ultra dialed in so that one can hold perfectly still in the water.

I posted this... you know... around. Every once in a while (read: when my wife reminds me to do so) I post something I've written to a couple of facebook groups or to a messageboard or two. Which I did with that article.

There was one bit of "feedback" that has genuinely been bothering me.

"If you cannot hold still, you will swim in circles. Pretty simple, stop swimming around in a circle. Do not need to read a "blog" to see why you cannot stop swimming in circles. Stop finning and you will stop spinning in circles."

I was tempted to point out that I will occasionally play a "game" with students.

I shoot an upline from 15-20 feet and place two markers on the upline three feet apart. The goal is to hover by the shallower one, horizontal and motionless as possible for one minute with everyone's pinky finger touching the cookie. Anyone who's finger comes away from the cookie for the minute accumulates a point against.

After the minute we descend, together, in formation, staying horizontal, to the lower cookie. Again, float a minute with pinkie fingers touching the cookie.

After the minute has passed we decide on someone to pick up the cookie and ascend, as a group, in formation, horizontally, leapfrogging up over the upper cookie by three feet. The marker is replaced on the line. Another minute of floating motionless.

Anyone on the team ascends or descends faster than anyone else by more than a foot... that's another point against. The team is completely broken up (someone sinks to the bottom, bobs to the surface, has to hold on to something for stability, has to swim around a bit to reposition, etc) that's an automatic disqualification.

Down to the lower cookie for a minute.

Leapfrog that cookie up. Another minute.

The entire excercise is, basically, a controlled, stationary, horizontal ascent from 15 feet that takes almost 15 minutes.

15 minutes. Of barely moving a muscle. And trying to maintain absolute position in the water.

It's hard. I'm pretty good at this stupid game, but it's still hard. Demanding on quite a number of physical and psychological levels. Takes teamwork, communication, and absolute control.
Best scores tend to be in the range of 10-12 points accumulated.

I thought about offering an entire Intro to Cave course gratis if the poster could actually make it through this game with a score lower than 30.

Every once in a while I post the things that I write to various fora. And get told that I'm stupid idiot with stupid ideas by people with 100 dives and 30,000 posts. Like the time I foolishly got into a debate about general deco theory with someone. Or the time I suggested that backing off 3rds was a good idea in many circumstances. Or when I suggested that even in open water the classic, horizontal "tech diver" pose is preferable for a variety of reasons.

Why bother trying to present information to people who obviously know so much more than I do? Which is why I tend to only post things "around" when Nelly "reminds me."
So, instead, I settled on throwing up my hands on the seemingly broad disconnect between what - and apologies for speaking in such broad strokes - the recreational world and the technical world tend to think of as "holding still."

Which is sad for those of us who start in the recreational world (as every single diver does) and decide to move over to the tech world... who wind up getting a very rude awakening about just how "still" we've been holding all this time.

*** Fun bonus tip ***
To ascend perfectly horizontally while maintaining neutral buoyancy the whole time:

Start, obviously, properly weighted for horizontal trim and neutrally buoyant.

Tilt ever so slightly head down without breaking a straight line from your shoulders to the knees, so you feet are just slightly pointed toward the surface behind you. Again, a gentle angle.
Give a tiny, half-back-kick, it will pull you slightly back and slightly up.

Level out and give a tiny, modified frog to shuffle you forward.

You have now moved about 6 inches upwards, with that short rock back-up and then forward your only movement has been up.

Reassess buoyancy and repeat.

If you're familiar with a trackstand on a bicycle... same thing, but moving upwards instead of waiting at a traffic light to cause an accident.

Tune in next week (or whatever time I think of it again) for pointers on how to swim sideways.
 
Sounds like a fun game, I want to try. It also sounds incredibly hard. My bet is that the critic would not take you up on that offer. Too much chance of losing face...

*** Fun bonus tip ***
To ascend perfectly horizontally while maintaining neutral buoyancy the whole time:

Start, obviously, properly weighted for horizontal trim and neutrally buoyant.

Tilt ever so slightly head down without breaking a straight line from your shoulders to the knees, so you feet are just slightly pointed toward the surface behind you. Again, a gentle angle.
Give a tiny, half-back-kick, it will pull you slightly back and slightly up.

Level out and give a tiny, modified frog to shuffle you forward.

You have now moved about 6 inches upwards, with that short rock back-up and then forward your only movement has been up.

Reassess buoyancy and repeat.
Hmm. Would you do this for OC also, or is this advice for CCR divers? Wouldn't it be easier on OC to slightly modify the breathing cycle?

EDIT:
Haha, I guess by that question you can tell I didn't read your blog post. I just went back to read it, and I saw that you make a point of advocating not using breath for buoyancy at all. It does sound like something that comes from CCR diving, though. In any case, never mind the question. Carry on...
 
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Hmm. Would you do this for OC also, or is this advice for CCR divers? Wouldn't it be easier on OC to slightly modify the breathing cycle?

Would I do it? Yeah. I also teach it as best practice no matter what's on your back (or sides).

There's a value in presenting a giant surface area to the majority of upwards and downwards water resistance. It helps maintain a static depth and true neutral buoyancy, so your breathing cycle can be natural and relaxed AND you can stop on a dime anywhere in the water column because you maintain neutral throughout the ascent. For any sort of decompression diving it's essential to maintain the ability to relax at a static depth during deco and the ability to instantly render aid to a buddy.

That said... for a 30 foot reef dive in calm blue water a perfectly controlled neutral, horizontal ascent is just showing off. There's no practical value to being the only wanker in perfect trim while everyone else is getting vertical because the boat is coming to pick you up. I mean... unless you really enjoy being a pompous wanker.

Which I do. So I'd still do it. But I'd be fully cognisant of the fact that it's a party trick at that point.
 
The team is completely broken up (someone sinks to the bottom, bobs to the surface, has to hold on to something for stability, has to swim around a bit to reposition, etc) that's an automatic disqualification.

OK, this is something that has bothered me for a while now, and this gives me the context to ask.

What do you do in that situation? There are two situations that get me:

One: a diver goes up. The remaining team are where they’re supposed to be. You tell them by signaling that they’re going up and need to come down. But they don’t. What do you do? I’m assuming the answer is go up after them, and the whole team sticks together. But what about a situation where there is a ceiling? Yes, someone with a ceiling certainly should be good enough to stay where they’re supposed to, but I have had it happen.

Two, and the more common difficulty I have with inexperienced divers. One goes up, one goes down. Now what? Obviously, the answer I would love is “dive with a better team”. But that isn’t possible. I’m not talking about technical dives, just trying to dive with people and help them to develop better skills, including teamwork. What am I supposed to do with that?


Here in the Midwest, finding capable divers is hard enough, but finding team focused divers is even harder. My instructor in my fundamentals class said “be the change you want to see“. So I’m definitely trying to do that. But it’s a struggle…
 
There's no practical value to being the only wanker in perfect trim while everyone else is getting vertical because the boat is coming to pick you up. I mean... unless you really enjoy being a pompous wanker.

Which I do. So I'd still do it. But I'd be fully cognisant of the fact that it's a party trick at that point.

Tell me you’re a GUE diver without telling me you’re a GUE diver…

And yes, I do exactly the same thing. :) Pompous Wankers unite! :)
 
Would I do it? Yeah. I also teach it as best practice no matter what's on your back (or sides).

There's a value in presenting a giant surface area to the majority of upwards and downwards water resistance. It helps maintain a static depth and true neutral buoyancy, so your breathing cycle can be natural and relaxed AND you can stop on a dime anywhere in the water column because you maintain neutral throughout the ascent. For any sort of decompression diving it's essential to maintain the ability to relax at a static depth during deco and the ability to instantly render aid to a buddy.

That said... for a 30 foot reef dive in calm blue water a perfectly controlled neutral, horizontal ascent is just showing off. There's no practical value to being the only wanker in perfect trim while everyone else is getting vertical because the boat is coming to pick you up. I mean... unless you really enjoy being a pompous wanker.

Which I do. So I'd still do it. But I'd be fully cognisant of the fact that it's a party trick at that point.
To clarify, I would of course adjust buoyancy after reaching the new depth. So the way I've been taught is:
- Neutral
- Slightly bigger inhale to start ascending
- Adjust buoyancy as needed to control speed of ascent
- Stabilize at new depth and regain neutral buoyancy

It seems easier/more practical to me than:
- Neutral
- Head down and back-kick-frog shuffle
- Adjust buoyancy to stabilize at new depth

However I assume you have better control of minute buoyancy changes than I do, and I do see the value of a method that would be the same on OC and CCR, since that's an adjustment many people struggle with.
 
There's no practical value to being the only wanker in perfect trim while everyone else is getting vertical because the boat is coming to pick you up. I mean... unless you really enjoy being a pompous wanker.
Bugger, OK OK I will resist being the pompous ......
I have been guilty of showing off, admit it, who else has done it? 🫵
 
One: a diver goes up. The remaining team are where they’re supposed to be.

During no-deco diving, there's no reason for a diver not to go to the surface (I mean, all things being equal - no boat traffic, no heavy surf, no swim throughs, etc). If the rest of the team is on the bottom continuing the dive and the separated diver is safely on the surface... who cares? Maybe they suddenly just got really hungry.

In deco diving, same answer, different reason. One diver leaves the group and ascends past a safe overhead... their team can't retrieve that diver without putting themselves at risk. They stay put.

And, of course, faced with these situations in the capacity of instructor the best answer I got for you is, "It depends." You take every step available to you to avoid such a situation happening in the first place, but on those occasions when it sneaks up on you... you take every step available to quickly and safely extract absolutely everyone out of it the moment it starts to look like it's going to spiral.


Two, and the more common difficulty I have with inexperienced divers. One goes up, one goes down. Now what? Obviously, the answer I would love is “dive with a better team”. But that isn’t possible. I’m not talking about technical dives, just trying to dive with people and help them to develop better skills, including teamwork. What am I supposed to do with that?

Really thorough debriefs.
 
Which is sad for those of us who start in the recreational world (as every single diver does) and decide to move over to the tech world... who wind up getting a very rude awakening about just how "still" we've been holding all this time.

I don't think if myself as the average recreational instructor, but my goal is to get every open water student to their final dive with the ability to get a gue tech pass of they take fundies.

I'm not teaching them to dive doubles, and I'll pass them if they can't do an efficient back kick, but I expect that they will walk away from their course with the ability to improve their own skills to the point where they can show up at a cavern/intro/etc class taught by someone I know and that someone will have a decent student who doesn't need to be retrained. I want to hear, "Hey. I just started teaching ____ and she looks really good in the water." In other words, I don't want them to have that rude awakening.

Most of the the time, that's an exercise in futility. Today, I taught two students who have the athletic ability to be beautiful looking cave divers, but ask they want to do is go look at fishes in vacation. It's refreshing to see then hovering and learning to back kick on open water dives three, but sad knowing they'll probably never want to be anything more than AOW and nitrox divers (if that).

Either way, @oya, know that some of us aren't the most vocal, but your thoughts and sentiments are appreciated. And one day, if one of my students shows up in your class, is like to hear that they they weren't a sh!tshow... Or, if they were, I'll take that feedback too.

Until that happens, please keep posting about things you're clearly wrong about. I mean, it's obvious that this are always way too conservative and you cave diver instructor types are just gatekeeping with your insistence on good trim and buoyancy. Vertical deco stops 4 life! 🙃
 
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