what causes yoyo motion while drysuit diving?

[ginti]

I think, my fins (mares avanti quattro) don't help as they are neutral (actually very slightly positive), so legs tend to float even with small amount of air in the boots. But, before I start making equipment changes I need to experiment more and see how it goes.

So, in reality, I would first try to manage to correctly purge your drysuit. Indeed, the air in the legs also affects other types of propulsion, which, depending on the kind of dives you (want to) do, could be important; this is especially true for the back kick. Also, if your legs are slightly positive (but you overall are neutral), you might be making some adjustments to counterbalance them - and some of these adjustments may be not positive to you.

Anyhow, heavier fins are generally something important when diving dry, depending on your suit (trilaminate or neoprene?) and undergarments... I have no idea of what fins you have, so I can't say whether or not they are a key contributor to your back kick issue...

But it's awesome that you already identified a potential issue

 

[kelemvor]

It takes usually a bit longer than 5 dives to get used to a drysuit.

This. When I got my first drysuit (only about 4 years ago) I had to complete 25 dives before I was allowed to do any further training in the suit. It does have a larger learning curve than other gear I'd used up to that point. I understand rebreathers are far worse.

 

[J-Vo]

Dry suits require more strength for stability, so if your core strength is already borderline or your not used to it, you will subconsciously lead from your head and shoulders rather than a stable core platform. This ends up looking like a head bobbing motion. Concentrate on tightening your glutes and kicking from your core. Maybe start doing some well rounded core strengthening if your not already.

 

[stepfen]

Dry suits require more strength for stability, so if your core strength is already borderline or your not used to it, you will subconsciously lead from your head and shoulders rather than a stable core platform. This ends up looking like a head bobbing motion. Concentrate on tightening your glutes and kicking from your core. Maybe start doing some well rounded core strengthening if your not already.

Interesting perspective. Actually I've been training regularly (including core of course) for one and a half years now. I would say 50-50 between cardio and resistance. Nothing extreme, just regular, consistent exercise. Although I still have long way to go, I see quite a lot of difference in my everyday life including diving of course.
So far though, I haven't though about incorporating core specific techniques to my diving. Tomorrow I am having two more dives and for sure that is going to be in my to do list.
Thanks a lot.

 

[BlueTrin]

If that helps I had a tendency to drop my knees while kicking.

If you slightly tense your back while diving by being a tiny bit arched (only a tiny bit, don’t need to overarch), and keep arms extended in front, then this helps me to not drop my knees while kicking (as @jvogt said)

A bit like the position you’d take if you were in free fall waiting to deploy a parachute if that helps?

 

[happy-diver]

 

[stepfen]

Nice picture @happy-diver. So far I knew back and side mount. Here I see front mount. Learning something new everyday

Anyway this morning I did only one dive as weather went bad during it.
I tried to experiment with core activation etc as @jvogt suggested. Ok frog kick gets much more powerful with glutes activation - I am pretty sure this is the way it is supposed to be so I will try to get used to this.
Also I noticed what @BlueTrin said above (arching a bit to prevent knees dropping).
Thanks for all the input

 

[VanHandyman]

And you dive "deep" (>20m) and in horizontal trim using only the drysuit for buoyancy, and you also find it easier than using the wing? You are the first person I met that find it easier to manage buoyancy with the drysuit in these conditions

Give it a try and let me know how it goes for you.

 

[ginti]

Give it a try and let me know how it goes for you.

I know the answer already: I need too much air in the suit, and I wouldn't say I like it. So I prefer to use the wing and put in the suit just the amount of gas required to move (and to be warm enough)

 

[Gareth J]

Cool! Still trilaminate, right? But do you find it really easier, or just more comfortable?

EDIT: I forgot to ask if in single or double tanks actually... with the latter, the amount of air needed in the drysuit is really a lot. I mostly know people diving doubles, which maybe explains why they prefer using the wing - maybe with a single tank it is easier, I really do not know

One of the reasons I think people use the drysuit for buoyancy, is that on a single cylinder, by the time you have taken the suit squeeze off, you are neutral.

I have dived most combinations, from single, to twin, twin with stages and CCR. Certainly on a single I never even think to put gas in the wing, if I do I'm far too buoyant. I only ever have the CVD closed down a few clicks.
On CCR or twin and stages, I do use the wing, because of the volume of gas needed to achieve neutral buoyancy.