Feedback on Trim/Buoyancy? (In Preparation of TDI Decompression Procedures Course)

[Random Dude]

Hi Scubaboarders,

I am TDI Advanced Nitrox certified (on twinsets) and will be taking my Decompression Procedures class somewhere around April 2024. Therefore, I've been going to the pool to brush up my skills.

1st Video (Video of me shooting an SMB and ascending (the line caught on the reel when releasing the SMB, will be practicing more on this)

2nd Video (Video of me hovering at a tcertain depth, the video taker was bobbing up and down a little, but I am maintaining the same depth throughout)

3rd Video (Video of botched attempt at using lift bag as redundant buoyancy, will be practicing more on this)

The videos in the Google Drive links above are from the 1st training session where I saw a few problems as below:

(a) I appear to have a bad habit of pointing my fins upwards (they are not parallel to the ground). The left fin appears more prone to this. What are the possible causes of this, and how should I remedy it? I suspect that it might have to do with me being head heavy, as I noticed that the more I tilt forward, the more my fins point up.

(b) When hovering, I have a tendency to keep sculling the fins. Some of the motions seem unnecessary to maintain station as they appear to be inconsequential flicks and wiggles here and there. These flicks and wiggles seem to intensify when task loaded. Is this indicative of some bad habit, and if so, any tips on remedying it?

(c) When hovering for extended periods of time, I realize that I tend to drift laterally ever so slowly (will usually end up orbiting laterally around my reference point if given enough time). I suspect that this has to do with my fins not being parallel (as described in (a)) and the constant sculling (as described in (b)) which causes unintended forces that pushes me laterally.

(d) When ascending, I always do this weird thing with my fins (sort of like pushing downwards with fins to create upwards force) to kickstart the ascent process. Is this practice common, or is it indicative of any buoyancy issues/bad habits? I suspect it might have to do with weighting as in this combination of doubles and wetsuits, I am probably a tad overweight in the water (will be doing weight checks on my next session to confirm on this).

Would love to have your thoughts and opinions on the above issues. Would also appreciate any comments in general on my skills, and suggestions to improve as well.

Thanks!

 

[crofrog]

Hi Scubaboarders,

I am TDI Advanced Nitrox certified (on twinsets) and will be taking my Decompression Procedures class somewhere around April 2024. Therefore, I've been going to the pool to brush up my skills.

1st Video (Video of me shooting an SMB and ascending (the line caught on the reel when releasing the SMB, will be practicing more on this)

Try to pay more attention to the team / depth gauge you’ll have a hard time doing that mid water spending that much time looking down so make sure you scan the team and gauge.

You look head heavy based on fin position.

2nd Video (Video of me hovering at a tcertain depth, the video taker was bobbing up and down a little, but I am maintaining the same depth throughout)

Looks good. Try to reduce sculling

3rd Video (Video of botched attempt at using lift bag as redundant buoyancy, will be practicing more on this)

The videos in the Google Drive links above are from the 1st training session where I saw a few problems as below:

(a) I appear to have a bad habit of pointing my fins upwards (they are not parallel to the ground). The left fin appears more prone to this. What are the possible causes of this, and how should I remedy it? I suspect that it might have to do with me being head heavy, as I noticed that the more I tilt forward, the more my fins point up.

I wrote the reply as I was going through the videos. I agree that you’re head heavy. The vertical fins are a sign i see almost always when people are head heavy you’re finning down a little bit to stay balanced. Move the weights down on your system if you have any and get that back plate lower.

(b) When hovering, I have a tendency to keep sculling the fins. Some of the motions seem unnecessary to maintain station as they appear to be inconsequential flicks and wiggles here and there. These flicks and wiggles seem to intensify when task loaded. Is this indicative of some bad habit, and if so, any tips on remedying it?

It indicates a rig balance issue to me. Your fighting to keep your head up.

Next dive don’t fight it just stop moving completely and see what happens. If you fall head first you know you’re not statically balanced.

When you’re doing tasks you’re moving very quickly. If your hands put a force into the water then your fins have to compensate for it with an equal and opposite reaction. Slow down

(c) When hovering for extended periods of time, I realize that I tend to drift laterally ever so slowly (will usually end up orbiting laterally around my reference point if given enough time). I suspect that this has to do with my fins not being parallel (as described in (a)) and the constant sculling (as described in (b)) which causes unintended forces that pushes me laterally.

Agreed probably sculling or a slight current in the pool it’s crazy how little current can move you around When trying to be completely still.

(d) When ascending, I always do this weird thing with my fins (sort of like pushing downwards with fins to create upwards force) to kickstart the ascent process. Is this practice common, or is it indicative of any buoyancy issues/bad habits? I suspect it might have to do with weighting as in this combination of doubles and wetsuits, I am probably a tad overweight in the water (will be doing weight checks on my next session to confirm on this).

I’d say it has less to do with being overweighted and more to do with needing slightly more gas in your wing to be truly neutral. You should be able start the depth change with just an inhale.

Would love to have your thoughts and opinions on the above issues. Would also appreciate any comments in general on my skills, and suggestions to improve as well.

Thanks!

Looking good overall. Try and slow down every thing you’re doing by half. The stuff above is fine tuning.

 

[Random Dude]

@crofrog Thanks for your comments, they were very helpful!

Will be going to the pool again this weekend to practice and work on the abovementioned issues.

 

[VikingDives]

I agree with everything @crofrog mentioned. You also seem to go head down when working on tasks. Make sure to keep something static (wall of the pool, line, teammate etc.) for a visual reference while you're doing skills.

You need to work on breath control. You're using your lungs for buoyancy control too much. If you watch the videos and time your breaths, you'll see what I mean. As soon as you find you're doing that, you need to pause your practice and get your breathing back in rhythm. Then get neutral before continuing your skill.

Your backup mask should be attached with a double-ender, and I'm not a fan of dropping things in practice. You can take the double-ender off the back up mask and put it on your primary before stowing.

Finally, I'd suggest slowing down a lot. Get neutral without finning, then start your skill. Do part and stop, check your breathing and buoyancy, and adjust as necessary before continuing.

Overall you look pretty good though.

 

[Random Dude]

@VikingDives thanks for the comments, appreciate it!

You also seem to go head down when working on tasks. Make sure to keep something static (wall of the pool, line, teammate etc.) for a visual reference while you're doing skills.

yeah, agree that I need to build up this habit, I guess in a pool I can get away with looking down and using the pool floor as a visual reference, but like @crofrog mentioned, that would not work out too well in mid water situations.

You need to work on breath control. You're using your lungs for buoyancy control too much. If you watch the videos and time your breaths, you'll see what I mean. As soon as you find you're doing that, you need to pause your practice and get your breathing back in rhythm. Then get neutral before continuing your skill.

yeah, I realize that I do over-rely on my breath for buoyancy control, this was especially obvious when I went for a rebreather try dive, as I blew through much more diluent compared to the other participants while maintaining buoyancy.

That's is an interesting perspective as the conventional teaching is to "control buoyancy using the lungs".

However, I came across this interesting article to the contrary, which makes a lot of sense to me. I guess the trick is not to "over"-rely on breath control.

Do Witches Sink in Water?

"If you can float, neutral, two feet below the surface without moving a muscle, that's when you've really got your buoyancy dialled in."An instructor at one of the first shops where I used to hang around making a menace of myself once told me that. Taking it as a dare, to this day, I frequently...

www.xoc-ha.com

I guess controlling buoyancy more with my BCD would also remedy the issue of having to use fin motions to kickstart the ascent, in line with what @crofrog mentioned on that.

Your backup mask should be attached with a double-ender, and I'm not a fan of dropping things in practice. You can take the double-ender off the back up mask and put it on your primary before stowing.

yup, point taken, I didn't think about stowing the primary mask as I was thinking more about the scenario where I "lose" the primary mask, but yeah, it's just a good habit to have in general, wouldn't want to just drop and lose my gear out of bad muscle memory when I'm practicing in the sea.

Finally, I'd suggest slowing down a lot. Get neutral without finning, then start your skill. Do part and stop, check your breathing and buoyancy, and adjust as necessary before continuing.

When you’re doing tasks you’re moving very quickly. If your hands put a force into the water then your fins have to compensate for it with an equal and opposite reaction. Slow down

Yeah, looking back to my videos, I do feel like that I'm rushing through the exercises. Probably cause I am still not 100% confident with the tasks, and subconsciously wanna "finish" the tasks as soon as possible so I can go back to the comfort zone of no task loading (which is counter productive to my aim of training to be better at those tasks). Will take note to instill this in all my dives, should work wonders.

Thanks again for the comments!

 

[VikingDives]

@VikingDives thanks for the comments, appreciate it!


yeah, agree that I need to build up this habit, I guess in a pool I can get away with looking down and using the pool floor as a visual reference, but like @crofrog mentioned, that would not work out too well in mid water situations.




yeah, I realize that I do over-rely on my breath for buoyancy control, this was especially obvious when I went for a rebreather try dive, as I blew through much more diluent compared to the other participants while maintaining buoyancy.

That's is an interesting perspective as the conventional teaching is to "control buoyancy using the lungs".

However, I came across this interesting article to the contrary, which makes a lot of sense to me. I guess the trick is not to "over"-rely on breath control.

Do Witches Sink in Water?

"If you can float, neutral, two feet below the surface without moving a muscle, that's when you've really got your buoyancy dialled in."An instructor at one of the first shops where I used to hang around making a menace of myself once told me that. Taking it as a dare, to this day, I frequently...

www.xoc-ha.com

I guess controlling buoyancy more with my BCD would also remedy the issue of having to use fin motions to kickstart the ascent, in line with what @crofrog mentioned on that.



yup, point taken, I didn't think about stowing the primary mask as I was thinking more about the scenario where I "lose" the primary mask, but yeah, it's just a good habit to have in general, wouldn't want to just drop and lose my gear out of bad muscle memory when I'm practicing in the sea.





Yeah, looking back to my videos, I do feel like that I'm rushing through the exercises. Probably cause I am still not 100% confident with the tasks, and subconsciously wanna "finish" the tasks as soon as possible so I can go back to the comfort zone of no task loading (which is counter productive to my aim of training to be better at those tasks). Will take note to instill this in all my dives, should work wonders.

Thanks again for the comments!

I just want to give you some kudos, because you're the kind of student ever instructor wants.

Ping me when you're an instructor, because you're going to be the kind of instructor in going to want to regret people to.

Also, well done not including your ego here. You're just putting your skills out there and accepting feedback - I'm impressed.

As to losing your mask - that's unlikely. In an andp scenario, it's more likely your mask is going to be leaking a little or just bugging you.

 

[crofrog]

@VikingDives thanks for the comments, appreciate it!


yeah, agree that I need to build up this habit, I guess in a pool I can get away with looking down and using the pool floor as a visual reference, but like @crofrog mentioned, that would not work out too well in mid water situations.




yeah, I realize that I do over-rely on my breath for buoyancy control, this was especially obvious when I went for a rebreather try dive, as I blew through much more diluent compared to the other participants while maintaining buoyancy.

That's is an interesting perspective as the conventional teaching is to "control buoyancy using the lungs".

However, I came across this interesting article to the contrary, which makes a lot of sense to me. I guess the trick is not to "over"-rely on breath control.

Do Witches Sink in Water?

"If you can float, neutral, two feet below the surface without moving a muscle, that's when you've really got your buoyancy dialled in."An instructor at one of the first shops where I used to hang around making a menace of myself once told me that. Taking it as a dare, to this day, I frequently...

www.xoc-ha.com

That’s a great article. I want to obtain normal tidal breathing at all times during a dive.

If I’m neutral when I’m breathing tidally when I take a big inhale or exhale I can initiate the depth change. Then as approaching the new depth I make a coarse adjustment on the wing. Then inhale or exhale to stop feel where I am in my lung and adjust the wing to allow normal tidal breathing again.

I guess controlling buoyancy more with my BCD would also remedy the issue of having to use fin motions to kickstart the ascent, in line with what @crofrog mentioned on that.



yup, point taken, I didn't think about stowing the primary mask as I was thinking more about the scenario where I "lose" the primary mask, but yeah, it's just a good habit to have in general, wouldn't want to just drop and lose my gear out of bad muscle memory when I'm practicing in the sea.





Yeah, looking back to my videos, I do feel like that I'm rushing through the exercises. Probably cause I am still not 100% confident with the tasks, and subconsciously wanna "finish" the tasks as soon as possible so I can go back to the comfort zone of no task loading (which is counter productive to my aim of training to be better at those tasks). Will take note to instill this in all my dives, should work wonders.

Thanks again for the comments!

It’s all a journey I look at my videos and always feel like I need to be slower and more deliberate

 

[Sebs]

Not having seen your videos, one of the best things I learned from my ITT instructor was to just slow down.

Shooting an smb? Be neutral. Check depth. Take out smb. Check depth. Unfurl smb. Check depth. Take spool and smb in left hand. Check depth. Inflate smb a tiny bit. Check depth. Fully inflate. Check and maintain depth.

Same with valve drills.

Once you've done this so many times you can incrementally skip the depth checks. It's not a race. It's about building your muscle memory and task loading ability.

 

[hefley343]

I never liked anything attached to me that I didn't need or was dangling and when I was diving some shorter steel twins I had a hard time with most the weight being higher, I'm 6'2". A friend gave me a weight that a local guy was making, it was a 10 pound lead bar that he had molded into a back plate and drilled multiple holes, so you could move it up or down on the plate, even hang it off the bottom a few inches, and adjust your buoyancy. I always really liked it and would have made them, but free lead has vanished around here and I don't dive twins anymore.