Maintaining Trim while motionless

[Lorenzoid]

Holding precise depth without a visual reference or focusing on the depth gauge is a whole 'nother level of difficulty beyond hovering in one spot. That's like ninja diver territory. I suspect there are many tech divers who can't consistently hit a target depth within +/- a couple of feet. It seems like you are setting the bar very high for yourself. If you are able to keep yourself within 5 feet of a target depth WITH a visual reference, you are doing very well.

 

[diver0008]

Small ankle-finning, or sculling, to keep the bottom half up is what I do. It's second nature now. I also generally have my arms folded out in front of me if I want to be low and level.There is no movement in any direction. The rolling to one side that you are experiencing is gear related.

 

[dmaziuk]

Ah yes, I see the problem now.... Looking up makes things SOOO much clearer...

Until the neck goes ow, snap. And then it gets complicated for everyone else.

 

[boulderjohn]

Just to nitpick: you can do mask clearing in a perfect horizontal trim, but you need a mask with a purge valve. For a mask without that, you'll have to go vertical to do it the way it's taught, or turn sideways to do it the way it's not taught.

I do mask clear in horizontal trim. So do all my students. It's not necessary to go vertical or use a nose purge.

I was exaggerating of course, but I cannot clear it completely while perfectly horizontal. OK, to be precise: face down horizontal -- physics suggests I could probably do it face-up. Maybe I should try that some day...

This specific topic is one of the examples I used in an article I wrote that is supposed to be published before long in the PADI professional journal--the Undersea Journal. Briefly summarized, the article talks about how instructional practices that are not consistent with the way we dive inadvertently teach students to perform the skills incorrectly. Mask clearing is one of my examples.

In teaching students to clear a mask, we teach them that as they exhale, they should tip their head back. Most instructors do not tell them WHY they should do this, though. The reason is that a diver in normal horizontal trim has the face looking mostly downward. When you try to clear the mask, the water drops downward because of the force of gravity and the air being added to the mask. The mask needs to be perpendicular to the bottom so that the water will run out the bottom of the mask and down the face. If the face is still looking down, the water will stay in the mask.

The problem is that beginning OW classes have been traditionally taught with the students kneeling on the floor of the pool. In that position, the face and mask are already perpendicular to the floor. In fact, as students struggle to get comfortable in that awkward position, they sometimes lean back so the face is often already past vertical when they start. In that position, it is not necessary to tilt the head back; in fact, it can be counterproductive to do so, with the face going toward upside down horizontal. Because of this, students learn the opposite of the intent of the lesson--they learn that they have to get the entire body vertical instead of tipping the head back in order to clear the mask.

 

[dmaziuk]

When you try to clear the mask, the water drops downward because of the force of gravity and the air being added to the mask. The mask needs to be perpendicular to the bottom so that the water will run out the bottom of the mask and down the face. If the face is still looking down, the water will stay in the mask.

Think about it: you must bend your neck to exactly 90 degrees to have the lens vertical while keeping your torso perfectly horizontal. Body: parallel to the bottom, face: perpendicular to the bottom, the bit in between: ouch.

 

[gfaith]

@RainPilot Since you are obviously a Sidemounter did you have to hover vertically head down and clear your mask? That was very different skill for me, but we got it done.

 

[seeker242]

I notice that in almost all cases the diver is not completely motionless, but is slowly moving his/her fins back and forth. Often its small and just using the ankles, but there is a this more or less constant back and forth motion that helps maintain balance. I have watched GUE videos, ISE videos, random videos, etc.

is there a specific pattern or style for this small fin movement I see. In other words, is it specifically taught, or do divers just learn to do it unconsciously to maintain trim.

Seems to me to be the latter, kinda like riding a bicycle, you learn how to do it by doing it.

 

[RainPilot]

@RainPilot Since you are obviously a Sidemounter did you have to hover vertically head down and clear your mask? That was very different skill for me, but we got it done.

I didn't do that skill specifically for sidemount but unusual attitude clearing was something I did from my DM course in 2004. I've made it a habit to practice that as much as I can.

The secret for me was to make sure I never pull the nose part away from my face to flood, in any attitude. As soon as I did that, I had half the Atlantic take up residence in my sinuses. The clearing part took some thought to work out but tipping the deeper part away becomes second nature. Eventually

@dmaziuk if you lie face down on the floor can you look up to see the TV etc? I find that my horizontal trim tends to have my back quite arched. If I do it on a flat floor only my pelvis actually touches the floor.

The bend radius makes my neck not quite have to go 90 degrees. That would be all the ouch indeed.

 

[randytay]

As a new diver, I have been working to improve trim and bouyancy control. I feel fairly confident in my ability to hold trim and depth, although with any task loading I can break trim and that is currently what I am working. For instance, staying fixed during a mask removal and replacement. The other issue is that if I become completely motionless I will slowly roll or break trim. Most recently I was slowly rolling to the left and back.

However, when I came back from my trip I started watching videos closely, and I notice that in almost all cases the diver is not completely motionless, but is slowly moving his/her fins back and forth. Often its small and just using the ankles, but there is a this more or less constant back and forth motion that helps maintain balance. I have watched GUE videos, ISE videos, random videos, etc.

So I have a few questions:
1. What is a realistic goal for holding trim/position with minimal movement? I assume no use of hands/arms, and very minor fin movements.
2. Is there a specific pattern or style for this small fin movement I see. In other words, is it specifically taught, or do divers just learn to do it unconsciously to maintain trim.
3. If one completely stops all movement, how long is a normal time before rolling/tilting occurs and trim breaks down.

Why dot you just take a course in it? The UTD Essentials of Recreational Diving or GUE Fundies is a good place to start

 

[DevonDiver]

th without a visual reference or focusing on the depth gauge is a whole 'nother level of difficulty beyond hovering in one spot. That's like ninja diver territory.

Here's one drill I use to develop higher-level buoyancy control and awareness that I don't mind sharing.. .

I lay a horizontal guideline and the students start by holding the line, changing to the blacked mask and holding depth and trim. It works very well - I think the removal of visual stimuli helps focus the mind.

Once students are relaxed and successful holding the line, we progress to a refinement where they make a loose 'O' with their fingers around the line. The aim is to not touch the line with their fingers...and they're still in black mask.

If you remember the old 'wire loop game' (see pic), then you'll understand what I mean about not touching the line...

In a relatively short space of time, the students will be hovering accurately within a few cm, in trim and with no visual stimulus.

I then put normal masks back onto them. We can progress to doing drills and skills whilst still keeping station (by viewing or light contact) with the horizontal guideline that I laid.

I'll task load the students with ever more complex skills, but insist that depth control, trim and situational awareness must not be compromised. The aim is to challenge the diver, but they must prioritize the fundamentals, not the challenges, at all times.

The next step is to deploy a vertical guideline (tied down at the bottom with a DSMB at the surface). I put markers on that line to indicate depth. Target depth indicated by a cookie and depth variation limits indicated by line arrows. We perform all skills keeping awareness of the indicated depth, and students should not exceed the depth variation limits.

This also builds situational awareness, as the students need to keep 'head up, eyes open' whilst performing all the skills.

Hands are for equipment, eyes are for awareness. I train the divers to manipulate kit and do skills without needing to look. The eyes stay up and open, maintaining awareness of their depth, position and buddy.

We then practice skills on that vertical line, keeping level with the depth indicator (cookie) and not exceeding the depth variation limits (line arrows).

Once slick doing this, we can do buddy skill practice with no other visual reference. A buddy team hovers face-to-face and aims to maintain eye contact throughout. One diver performs a skill using his buddy as the depth reference. The buddy is responsible for holding accurate depth... being that reference.

If the diver performing skills does momentarily lose situational awareness, the supporting diver will signal them with a tap on the head... or make light contact with them. This also fosters improved team diving and mutual support.

It works really well... really quickly.