Maybe strange question? Sinking legs

[Dhboner]

Clench your butt cheeks and keep your knees up. Keep your chin high and look forward not down.

 

[Superlyte27]

What fins are you using. Jet's, F1's and several others are very negative. It might not matter how much you shift weight or eliminate weight if you are using F1's that are 3lbs negative.

Imagine strapping 1.5lbs of lead on each ankle. Will what you do to your belt or shoulders change what your ankles do? Nope

 

[boulderjohn]

You could try shifting some weight onto the top of the tanks with a trim pouch and second tank band too. I was trimming into "dying cockroach" pose with my drysuit until I moved some weight off my waist to high up on the tank.

This is a fast and simple way to make a lot of adjustment to you trim. You can get pockets from companies like XS scuba that you can attach to cam bands. You can then play with the amount of lead you put in the pockets until you are nicely trimmed out.

Changing fins, as others have suggested, can also help. I use heavy Hollis F1s with my dry suit and light Mares Quattro + with a wet suit. It makes a big difference.

 

[Ayisha]

Lots of great suggestions. Get neutral and just stretch out and see which way you tip, if at all. Don't move a muscle or correct in any way, just let yourself relax and fall. Sometimes it's the opposite of what we think but we are subconsciously making tiny corrections and compensating for what's really going on. Once you see how you fall, then make adjustments to your tank and weight placement and do it again until you lay flat and neutral without moving at all.

I use UTD Precision Neutral fins, which are the same size and shape as Jetfins but about half a pound lighter. They are awesome! Between adjusting the tank and weight placement and switching to lighter fins, I was able to achieve flat trim again with newer equipment that I had switched to.

 

[Joyinthewater]

Great info and suggestions! Thanks everyone!
I never thought a ought fins. Mine are really old, from 20 yrs ago.
So I'll look into that too.

---------- Post added December 29th, 2014 at 01:25 AM ----------

Cam bands are the band around the tank?
Thanks for great info!

 

[decompression]

Great info and suggestions! Thanks everyone!
I never thought a ought fins. Mine are really old, from 20 yrs ago.
So I'll look into that too.

---------- Post added December 29th, 2014 at 01:25 AM ----------

Cam bands are the band around the tank?
Thanks for great info!

Yes, cam bands are the ones around the tank.


Sent from my iPhone using Tapatalk

 

[Diver0001]

So I've been diving in cold water with a 7ml quite a bit.
I have a trip to Fiji scheduled and I'm super excited.
but I'm noticing that I'm missing the wet suit buoyancy affecting my trim, crazy as that sounds. I really like a horizontal trim in the water with my legs slightly higher than my head. Without the neoprene, if I am resting and still, my legs sink.
Not a huge deal but I'm wondering if anyone else has run into this and found a solution?
Thanks!

Let me build on the responses already made and lay this out perhaps a bit more fully.

Achieving neutral buoyancy AND your desired trim, which is usually stable and horizontal when at rest, is a question of a few interconnected elements:

1) having the right amount of weight
2) where you attach the weight
3) your body position in the water
4) your breathing

Regarding #1. In your OW course you learned how to establish how much weight you need. This will change as you gain experience (or gain/lose weight) and it will change with every modification you make to your gear configuration. It also changes due to salt content in the water, etc. It is a skill that all divers should master and apply regularly. I've been diving for 30 years and when I go somewhere new or change my gear, I still do a buoyancy check. Learn it, master it, practice it, apply it.

The reason this is so important is because if you don't have enough weight you will obviously struggle to stay under water and if you have too much then you will need to compensate with air in your BCD, which will cause an air bubble surrounding your upper body to pull your upper body up.... and therefore your legs will sink. Your problem, therefore, could be as simple as having more weight than you need. Think of air in your BCD as "pulling up"

Regarding #2. WHERE you attach the weight to your kit has an impact on whether or not you will tilt forward or backward. It's like fulcrum. The more towards your head the weight is, the more your head will be "pushed down". Likewise the more towards your feet the weight is attached, the more your feet will be "pushed down". There are several places on your kit that you can attach what we call 'trim weights', which are weights of +/- 1kg that are there to have the effect of balancing your fulcrum. I just drew the attached picture. Please forgive me, I have the artistic talent of an ape. If someone can make this picture look right, please by all means use it.



The idea is that you can attach trim weights to several places
- ankles,
- waist
- bcd pockets
- the tank
- the cam-band
- the tank neck
- trim pockets in your bcd. usually these are on the back of the bcd behind the shoulders

With the following comments:
- ankles should be avoided imo because attaching weights to your ankles makes swimming heavier.
- the waist and bcd pockets are where most of your weight will go. If your feet are going down it could mean that you have too much weight here. If you WANT your feet to go down you could consider adding an extra kg here
- there are after-market pockets you can buy to attach weights to the cam band. Don't just attach the weight to the actual cam-band. This could cause issues with securing the tank properly.
- if you attach a weight to the tank (other than the cam band) then use a *separate* cam-band and pockets (shops sell these). NEVER use a weightbelt for this. It will fall off.
- also moving the tank up and down (higher/lower) will affect your trim
- the tank neck is possible but you seldom see it. IF you decide to do this, use an ankle weight and wrap it around the valve. In my experience this is seldom necessary.
- gear can also have intrinsic bouyancy (positive or negative) a good example of this is fins. Some sink, some float. You can use this to your advantage.

One thing that is really important to remember here is taht trim weights are often not ditchable. The majority of your weight should still be on your waist or in the BCD pockets so you can ditch it if necessary.

Regarding #3. Your body position is something you can control to some extent. For example, you can extend your arms out in front of you to bring your upper body down. The position of your head also matters. Where you look is generally where you will go (the body follows the head). If you look up, your feet will tend to sink. If you look down, they may feel more neutral. Of course you can only play with this to a certain limit. Your back is also important. If you "hole" your back (gut out), the position will cause your hips to sink because your back is attached to your pelvis and your head. We use this with drysuit diving a lot to get back to balanced if the feet start to float away. Likewise, holding your back straight or rounded will affect your position. You can use this to make "fine" adjustments as you go. You'll soon realize that "perfect buoyancy" is akin to driving a car in a perfectly straight line. You need to make constant fine adjustments, just like you can't let go of the steering wheel while you're driving. Moreover, just like driving, it becomes fully automated (you don't have to think about it anymore) as you gain experience.

Regarding #4. As you breathe in and breathe out you will go up and down the water column, of course. What breathing in also does is make your upper body more buoyant until you breathe out again. The reason a lot of new(ish) divers need more weight in general and may have more challenges with heavy feet is *can* be related to keeping more air in the lungs than is necessary. The more you relax, the less air you will be keeping in your lungs (as a general rule) and this will affect your buoyancy and trim. What I tell my OW students is that every time they breathe out they should release the tension their muscles and relax into the "zen" feeling of diving. This means diving slow, trusting the gear and pushing boundaries slowly.

I hope this post will help you put it all together and give you a context that you can use to understand the big picture.

Good luck.

R..

 

[Joyinthewater]

R,
Thank you so much! I am fascinated by Bouyancy and have read several articles and this is so
much more helpful info! I really appreciate you taking time to explain (and draw!) it all out for me.
Im very glad I asked this question now because I've learned a lot. I'm saving a copy if your answer to study. It's hard because I live in Utah so most of my diving is in a 7ml with an occasional freshwater warm dive. Hard to practice for Fiji. But I feel like by using the principles you've explained and continuing to work, I'll keep improving and I'm sure I will have a fantastic time in Fiji. Thank you!!!

 

[Cosimo_Zaretti]

So I've been diving in cold water with a 7ml quite a bit.
I have a trip to Fiji scheduled and I'm super excited.
but I'm noticing that I'm missing the wet suit buoyancy affecting my trim, crazy as that sounds. I really like a horizontal trim in the water with my legs slightly higher than my head. Without the neoprene, if I am resting and still, my legs sink.
Not a huge deal but I'm wondering if anyone else has run into this and found a solution?
Thanks!

Not just you. I recently spend a week diving in Thailand and really struggled for trim. I kept finding myself floating head up and was having to concentrate to hold a hover with my fins off the reef. I took over my usual BC, boots and fins, only variable was wearing my 3mm suit. As soon as I got back to Sydney I went out in my 7mm and it felt great. I had a nice heavy steel cylinder (why does every operator in SE Asia use AL80s?), and my arms and legs were just a little bit bouyant. All the weight was distributed where I wanted it allowing my legs to just float up nicely behind me for a much easier kick.

 

[AfterDark]

IMO it just means that you have a lot of leg muscle. Fat floats muscle doesn't and the better developed and stronger the muscle the more it weighs by volume. Put some kid floaties on your ankles

For years I couldn't float my legs would drag me to the bottom of a 10' pool if I held my breath that long. I got a pass on that part of the swim test after doing just that to demonstrate that I wasn't capable of floating because my legs were negative. Time will take care of your problem it did for me!