What am I doing wrong? Buoyancy problems?

[haumana ronin]

Sorry for the delayed response, but

Rather than screwing up your trim to make it easy for you to tip your head back, why not learn to look up in a different way than craning your neck? There are ways, trust me. I often hear this excuse for not wanting to move the tank up

How? I use that excuse(for lack of a better word) for putting my tank low.

 

[Quero]

Sorry for the delayed response, but



How? I use that excuse(for lack of a better word) for putting my tank low.

Well, for one thing, most divers who complain about banging their heads are trying to change their viewing angle by moving their whole heads instead of just swiveling their eyes. Think about how you glance in the mirror when you're driving--do you lift your whole head up to check your rear-view or do you just swivel your eyes? Most people move only their eyes, so if you want to look at something higher in the water column than simply straight ahead of you, simply use your eyes to look up! Occasionally what you want to see is so far above you that you really can't just glance upward; in that case turn your head to the side (towards one shoulder, and look to the side and up with one eye higher than the other. This movement is something like checking your side mirror while driving--you do turn your head a little, but you also swivel your eyes to the side.

If your first stage has a turret, you can reposition it so that it extends downwards towards your back rather than upwards towards your head. You might have to take the hoses off and switch which ports they are attached to, but turrets can normally be pointed downwards without any issue.

IMO, your tank should only be placed low if that's the best position for it in regards to weight distribution. It shouldn't be shifted low because you're worried about bumping your head. When I'm diving, I can pretty much always feel the first stage brushing against my mask strap or my hair.

 

[Peter69_56]

Just a few notes that might help. Something I have seen that causes people to hit their head on the tank valve are, a loose fitting BCD sometimes too big for the user. Once they hit the water it shifts up on their body, thus the tank is much higher than when on land. The BCD needs to fit neatly. Secondly with regard to buoyancy issues, often I see people who are nervous and thus breath hold somewhat and shallow breath at the start of the dive. This causes them to not be able to sink due to semi inflated lungs, and so they get additional weights to compensate for this. Soon as they are under the water and start to settle they breath more deeply and so now feel too heavy. They then dump weights and then next time they hit the water, they again shallow breath thus have constant issues. Easiest thing to do to at least get a basis from what max weight to start with, is to completely empty your lungs at the start of the dive and weight yourself until you just sink down. This is now a good starting weight and you should be able to dive on this. After a number of dives doing this, and particularly if they recognise it as an issue, they seem to relax more and this issue then goes away. Then its a matter of how buoyant you are with a near empty cylinder. Maybe an extra lb or 2 if needed to stay at your safety stop and all is well. Remember as you breath in and out you will move up and down a bit in the water column, this is normal.

 

[Progen]

[video=youtube_share;i0h7L6x4eZk]http://youtu.be/i0h7L6x4eZk[/video]

After 4 months and 10 days, this is where I've arrived. It's the first time that I've gotten myself recorded and from what I can see, I think I've either 1. overdone the straighten your back thing or 2. will benefit from heavier fins which I'm intending to get anyway (probably the Hollis F2s or Dive Rites because I find the flexible blades of the X-Streams not giving much feedback) which is why my legs seemed to be rather floaty although in my defense, I was trying to follow the pool floor. I'm allowed to use this nice pool and the 5 metre diving one sometimes so that helps a lot since the sea isn't nearby.

 

[TSandM]

Looks pretty good to me -- going downhill, yes, you are head-down, but coming back up, you aren't. I would say not to separate your legs quite so much in the loading phase of the kick, and to pick your head up a little more (if the tank is too high to do that, you can lower it; it will do nothing but make your trim better). But overall, and especially given that you are using fins that don't give you real good proprioceptive feedback, I think things look darned good.

 

[Quero]

I actually think you're looking quite good there! notice how your thighs are in a straight line with your torso, even when you're going down the slope to the deeper water and how your fin blades are pretty much at the right angle. All I see is a sort of hesitation and what seems like a little lack of confidence that comes from "being watched," even if it's just being watched by a camera! I say, "Well done!"

 

[Progen]

Actually, it wasn't hesitation whenever I stopped. It was sort of a self buoyancy check and an ego thing to show that I was in total control. Back when I hadn't gotten my weighting dialed in yet (overweighted as are most beginners), I was compensating by inflating the aircell and with poor form amplifying the problem, I had to compensate by finning slightly upwards or else I'd be scrapping the pool floor because I wasn't actually moving parallel to it and neither was my body horizontal.

I had a bad feeling that my legs were opening a bit wide during the loading as pointed out by TSandM but I couldn't confirm prior to this because whenever I turned to look, off went everything.

I've really learnt a lot from those shallow pool sessions so from one beginner to another (not referring to those who've commented), take every chance you have to dive even if it's only in 3 feet of water. In fact, I found that I'd learnt the most during those sessions because if you're wrong, you either become a free pool floor cleaner or the idiot with his fins sticking out of the water. It also taught me the importance of keeping the hoses neat to the point that I've shortened my inflator hose by about 2 inches and have a bungy with a cord lock to secure it even closer to the harness.

 

[Progen]

Reached a new level of enlightenment today!

Having used and practiced with the Mares X-Stream fins which were positively buoyant at first and then slightly negative with the steel straps, I had to compensate by using the core muscles to pull my body and legs level. That threw me off proper horizontal trim every now and then since it required conscious effort to fin in such a way that I didn't descend with each stroke.

So I got myself a pair of Scubapro Jet fins with the steel straps yesterday and tried them today in the pool. Bloody hell!!! Suddenly, it became SO EASY to stay horizontal because the heavy Jets didn't require me to contract my core muscles to bring my legs down. I finally knew the meaning of bottom feeder because I was just an inch from the pool floor most of the time without any danger of contacting it. If anyone had told me the core muscles were important, I'd have shooed them off as pure rubbish because now that it's second nature to have to keep them tensed to compensate for the floaty fins (the Mareses), I was so relaxed and the modified frog kick with the Jets took me about the same distance that the much softer blades of the X-Streams did with the full frog kicks. And I finally knew the meaning of glide because I could see the pool floor sweeping by in between strokes.

So right now, I'm so horizontal that it's sinful and I actually had to intentionally fin diagonally upwards to get myself to touch the pool floor.

 

[Quero]

Kudos to you! It's a lot of fun to follow along with your development as a diver through this thread, so thanks for the update.

 

[TSandM]

Well, it all goes back to the quotation in my sig line . . . Glad to hear you found an easy solution!