Struggling to understand buoyancy and trim wearing my gear

[seaway2121]

I took a private fundies class in N Florida but feel like I wasted it because I couldn't stay horizontal. I have about 40 dives, always in rented jacket BCD. New to W/BP and proper technique.

I was wearing a two piece 7-mm neoprene suit, which we determined required me 18 lbs to be neutral (without other gear). I rented a neutral W/BP (Aluminum) and neutral fins, and steel 80 but my feet kept floating up. If I "relaxed", I would nose dive completely vertical within seconds. The only way I could stay horizontal was to maintain forward momentum.

The instructor was certain that my nose dive was due to poor technique. He explained my arched back and feet angled up, but I feel that those symptoms were only to compensate for the rapid nose dive. I would need to kick my feet up and lift my head to stay horizontal, which resulted in arched back and feet against my butt. Even after resetting myself with my legs extended and head up/shoulders relaxed, I would nose dive again.

We went over the physical of the body and how I needed to balance the fulcrum between my torso and legs by keeping my should blades relaxed, back straight, and fins up and out. I genuinely believe what the instructor was telling me, but I couldn't get past this nose dive in order to focus on other skills.

I think I really need to practice on my own, but I'm still not convinced I was weighted correctly with that wetsuit.. and maybe that had to do with the nose dive? I don't want ankle weights.. I want to figure this out through proper technique only. I think my other fins are positive though, so I don't know where to start with this fine tuning.

Also the littel bit of air in the wing would tilt me left or right, and maybe even contribute to the nose dive.. not sure.

Advice? Thanks.

 

[Bubblesong]

Following, where were you carrying the 18b weights? I carry my 8lbs in attached in front pockets of BP/W harness.
For the tilting, it sounds like the air in wing is not distributing evenly, so what type of wing? You were in Florida, so it seems like the smaller warm water wings would distribute air quickly.
My experience:
I wear a 7mm wetsuit, 4lb steel Freedom BP, 32lb Hog wing, Steel 80’s on my 160lb 5’2” self and only need 8lbs weight, and I put the tank as low as it can go, harness webbing fits close with just the fist space under it.
i can position myself upright or head down as needed for photography, but while hovering i don’t tip.

 

[James79]

I'm not a GUE type, but how I got my weight and trim sorted was at the springs (pool would be as good) I took a tank with 500 psi and a bag-o-weights to 15 feet. Dropped or grabbed weights (without worrying about trim) until I was neutral (holding them on a belt held in my hand allowed me to get neutral in a reasonable position). After that, I distributed the new known weight between trim pockets and weight belt at my best guess. Get neutral in a horizontal position, and just stop moving..... If I go ahead down, weight distribution needs to move down my body, head up- weight moves up. If I turn turtle, weight to the front. Once all that s done, if I can't turn turtle on purpose, weight to the back.

Whole process for me and a buddy took about 30 minutes in and out of the water, and now my trim is whatever I choose and easy to maintain.

Of course, my advice is worth what you paid for it, lol.

Respectfully,

James

 

[AfterDark]

I have the same problem when I use my dry suit boots with my wet suit, the boots are positive, so I use 1/2lb ankle weights. That may not be an option for you, however.

 

[Gone for diving]

I assume you have a nice heavy pair of fins?
I know that as a new ish diver, it takes some practice,, when I did my first drift dive I couldn't keep my feet down, felt like the water kept trying to flip me over,
I tried ankle weights, then got nice pair of heavy turtle fins, and got rid of ankle weights,
Now I can use any fin I want, though I prefer my turtle fins.
What changed? Experience, practice,

Maybe ankle weights for a few dives might help your form, and you'll notice you are feet heavy. And you can get rid of them, the weights.....
And really try to do a dive or two and practice no movements just trim out relax maybe a bit of kicking, but be aware of what subconsciously your legs are doing, I find new divers have a really hard time not moving their legs, and that effect can cause all kinds on bouyence movement,

 

[AfterDark]

The heavy fins are another way to go although depending how much they weigh it may be too much. The ankle weights I use when I do use them can be any weight I require, one end is Velcro so I can add or subject just the right amount of shot for the correct weight. I put one of my dry suit boots in seawater and added weight until it sank slowly to the bottom.
That came to just over 1/2lb, that's how I came to use 1/2lb in the ankle weights.
I could do the same thing by sticking a couple of 8OZ fishing sinkers in my boots.

OP may have a buoyant fin boot combo in which case different fins would definitely change things.

 

[inquis]

Have a buddy support you under the chest & thighs in good trim (torso/thighs horizontal, legs bent 90 at the knees). They will then remove their support, but you should NOT move/kick/wave hands/etc. If you rotate head-down from there, you should shift some lead toward your feet and try again. Possibly shift the tank downward a little, but not so much that you can't reach the valve. (There is a bit of technique to that as well, though.) If you get all your lead on your waist belt and still rotate head-down, investigate less buoyant fins or ankle weights.

 

[inquis]

Are you using an HP80 steel tank? I think those are fairly short, which biases the mass "headward" of your center of mass unless you are also short. Again, first see how things go after shifting all your lead to your waist. A longer tank (e.g., HP100) will help if you're still rotating at that point.

 

[wnissen]

I'm only asking this question because it's germane, but are you fat? I'm obese BMI-wise and I need 26 lbs. with a brand-new 8/7mm wetsuit, hood, and boots, with light fins, a steel 100 and traditional BCD. 18 lbs. seems like a lot for a non-obese person with your gear configuration. The plate (even neutral), and fins are going to take off at least that much. Simple physics says the more weight you're carrying, the more opportunities you have to get it in the wrong place.

As others have said, you need to get to a pool in your gear. Did you have a chance to do that before your Fundies course? No point in trying to make large adjustments when dealing with everything else. Start with way less weight that you think you need. I was taught to do a weight check at the start of a dive by taking a normal breath at the surface and holding it (the only time you're allowed). Correct weighting would hold you at the surface roughly at eye level.

Once you've got the amount set, start moving it around. If your head is dropping, move the weight as far back and as low as you can. It's easier to get completely relaxed when you're in the pool. Ideally you should be able to get horizontal and just float up and down. Take your time. Good luck!

 

[seaway2121]

Have a buddy support you under the chest & thighs in good trim (torso/thighs horizontal, legs bent 90 at the knees). They will then remove their support, but you should NOT move/kick/wave hands/etc. If you rotate head-down from there, you should shift some lead toward your feet and try again. Possibly shift the tank downward a little, but not so much that you can't reach the valve. (There is a bit of technique to that as well, though.) If you get all your lead on your waist belt and still rotate head-down, investigate less buoyant fins or ankle weights.

Thanks.

The instructor did this in the pool. He tried manipulating my body a lot. Each time I would feel completely relaxed and still nose dive when he let me go. He said I needed to keep my head up, shoulders relaxed, and legs straight with bend at the knees. I couldn't figure it out.

I think the tank was HP80, but it didn't seem any shorter. We also used AL80 on the first day, but had the same issue. I had 9lbs in each weight pocket of the harness near my waist, and I'm pretty sure the tank strap was right below the crown/shoulder of the tank.

In other words, I don't think I could put the weight any lower...

Perhaps this setup doesn't work well with double 7-mm suit and boots? The fins he rented me were neutral.