Hey! I've been diving commercially for a couple of years. My philosophy (this might not be ideal for everyone, but it works for me), is to be very slightly negatively trimmed with my BCD/dry suit when maintaining depth, and then use my lungs to "make up" the difference. So when I breathe in a normal amount of air I am neutrally buoyant. I have a quite slow respiration rate when diving, so I "hold" my breath for a few seconds before exhaling normally and inhaling normally. I believe the "trick" to buoyancy control is to be relaxed and comfortable, and keeping your heart rate and respiration low. Do everything in "slow-motion",and try not to exert yourself too much. The more energy you use, the more oxygen you consume.
this post was submitted on 29 Jul 2023
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You are doing it right; it just isn't easy yet- you just currently need a little more air than that. Getting in the habit of slow breaths forces everything else. As you calm down and become more economica in your movements, your breath tidal volume will decrease, and so will the bob.
Also: deep breath does not mean "max" breath. The SPEED is the important part.
Everyone bobs a little at rest if they are maintaining a normal respiration cycle. You can limit the bob by lowering the size of thel breath as you stated above- this gets easier as you get more comfortable on less air, which is a function of both mindset and developing exonomy-of-motion and economy-of-thought experience. When you get well and truly bored on the safety line, you can get that heart bpm down below 60 and it gets easier.
THAT SAID:
We don't control buoyancy to a station keeping point except for pictures and interacting with structure. Most of the time, the ask is to "swim at about this depth" in which case you either take reasonable breaths and not exhale all the way to ascend, or take reasonable breaths and exhale everything to descend. I call it breathing "out of the top" or "out of the bottom" of your lungs.
Easiest way to learn in shallow water, btw, is putting your hands behind your back and doing "finup" planks with your nose to the sand. If your nose hits the sand, you goofed.
Final tip for dealing with going ,up-and-dowm on dives, adjust your angle-of-attack and head either a little bit down or a little bit up to counteract.
Another piece of advice is to learn the frog/back kick as soon as possible. You'll eventually be able to do a lot of the fine tuning with your fins.
When you're trimmed properly and have good control over your fins, you can make the adjustments you need while hovering an inch off the bottom without stirring up any silt.
I have been working on that. The frog kick bothers one of my old knee injuries, but I've been figuring out how to get it with less strain on the knee.
What kind of fins are you using? My usual line to my students is that there's 2 kind of fins: jet fins and bad fins.
But the exception is for knee and ankle issues. Jet-style fins can be real tough on them.
Look into the Scubapro Seawing Nova fins if you haven't. All my students with knee and ankle problems that have tried them swear by them.
Not one hundred percent sure without looking, but I think it's these or very similar. Dunno if these are jets or bad.
https://us.aqualung.com/en/aqualung-master-catalog/shot-fx---dive-fins-FA166.html
I'll look at those scuba pro ones before the next trip.
Appreciate the insight, thanks.
Those aren't jet-style, no. They're also not great for back kicks and helicopter turns because they're "floppier" than you'd typically want. With floppy fins, you tend to get a lot of forward propulsion in the first part of the back kick because the tips bend up or down. It's like trying to push a garden hose - it can be done, but it's not very efficient.
Seawing novas do it a bit as well, but their rear "wing" kinda self-trims a bit on the backwards motion to minimize it. Jets (big, heavy, stiff fins designed in the 60s and still the de-facto standard for commercial, military, and tech diving) really do the best job, but they're pretty hard on the joints.
I swear I'm not a Scubapro shill. I think their computers are underwhelming, their BCDs way overpriced, and their top-end drysuit is my worst Scuba purchase ever.
But they do make some great fins.
Oh cool, I thought "jet" was a style of fin, not a specific model. I'll pick up some of those seawings before my next trip.
I will be entirely unsurprised if the fins I bought mostly at random because my OW cert shop required it turn out to be half my frustration.
Thanks for the advice.
Hey, 7 months later, just finished my first dive trip with a pair of seawing Nova fins. Excellent advice, thank you.
I'm addition to making the finning easier on my knees, they're more buoyant than my other fins, so my trim was better, making wrecks and the Cenotes cavern much easier.
Thanks!
That's great to hear! Glad I could help.
Well, there's a ton of fins that other companies have made trying to replicate them, and that's what we mean by "jet-style."
Some of them are even pretty good. The Apeks RK3s are pretty popular in the cave/wreck crowd since they're similar to jets but a little shorter, so they're trading off a little power for better maneuverability in tight spaces.