Descent difficulty, even overweighted

[Bubba_in_cali]

Hello, there. I have difficulty descending, and I have been trying to solve this problem with my scuba instructor. My next dive with her will be the PADI buoyancy course, but I would like to solve this newbie problem before doing that, if possible.

Here is my situation:

• body weight 165 lbs
• aluminum 80 cu ft tank
• soft lead weights, 22 lbs
• vest-style BCD
• 7mm wetsuit, Henderson Greenprene
• open water, Pacific Ocean, Casino Point, Catalina Island

When I attempt to descend, I deflate the BC and I exhale. My head will submerge, but just a couple of feet below the surface my legs float up, either putting me in a sitting position or in a prone position. I am unable to keep my legs below my body. As soon as my legs float up, my descent stops.

At that point, I usually grab a buoy line and descend hand-over-hand. But even during this process, my legs insist on putting me in a sitting position instead of a standing position. I want to be able to cross my ankles and just sink, like everybody else.

Hmm, actually there is something that I forgot to do on my last few dives: I forgot to remove air in the legs of the suit before entering the water. I may have had a fold in the suit near the ankles. Maybe that's why I had trouble descending.

What say you, please? Is leg buoyancy a known property of Henderson Greenprene, or am I making a common mistake somewhere here?

Thank you for your help.

-Bubba

 

[tomfcrist]

Honestly, I don’t see the problem. You should be in the prone position while diving. Decending, Ascending, swimming…all prone.

 

[J-Vo]

Are you saying your legs are out in front like sitting on the floor?

This is not lite legs, lite legs would pull you head down with feet up. I think this is due to you leaning backward and the tank is pulling you further.

Make an effort to lean forward and belly down in the proper dive position. Then hold that exhaled breath a bit longer and only take small breaths until you get 10-15' down. Your probably inhaling a big breath just after submerging and bobing back to the surface.

Additionally, new divers typically have no idea how much gas is still in their BC. In the belly down (sky diver)position it's easy to go a little head down and use that butt dump on your BC.

 

[UofMI_Divegeek]

If only the head descends and you immediately ascend, then you are under-weighted.

I have never heard of this feet rising issue. But, since I am not a fan of ankle weights, my first suggestion would be to use non-buoyant fins.

I usually set student buoyancy with student directly in front of me, so they can be controlled if initially too heavy.

For fresh water in standard wet suit start with 10-12% body weight. Salt water would be slightly more weight. (This is typically less weight than ideal, but best to start light and add weight)

Try this to set your buoyancy:
Have ~ 500 psig in your tank
Place regulator in mouth
Deflate BCD ... make sure it is totally deflated
Add or subtract weight until you float at eye level
At this point, exhalation results in descent and inhalation results in ascent

If weight is set at end of the dive with ~ 500 psig, then at the start of the dive with a full tank you will be slightly heavy and should sink on exhalation.

It is best to descend feet first as the pressure differential across the head assists in equalizing middle ear pressure.

 

[dmaziuk]

At 165 what's your waist size? More specifically, an average wetsuit is tailored for a beer pouch, if you don't have one, you'll likely have an air bubble there. Have you tried pulling on the neck seal to let the water in and the air bubble out? (When vertical on the surface, before you you go down.)

 

[Wibble]

If you can descend the first three feet, you’re not underweighted.

If the tide is running and the anchor/shot line is pulling away from you, you will need to go down hand over hand, the current will pull you flat. You release at the bottom where the current is weaker, or you’re tucked in behind the wreck/reef.

 

[VikingDives]

Hello, there. I have difficulty descending, and I have been trying to solve this problem with my scuba instructor. My next dive with her will be the PADI buoyancy course, but I would like to solve this newbie problem before doing that, if possible.

Here is my situation:

• body weight 165 lbs
• aluminum 80 cu ft tank
• soft lead weights, 22 lbs
• vest-style BCD
• 7mm wetsuit, Henderson Greenprene
• open water, Pacific Ocean, Casino Point, Catalina Island

When I attempt to descend, I deflate the BC and I exhale. My head will submerge, but just a couple of feet below the surface my legs float up, either putting me in a sitting position or in a prone position. I am unable to keep my legs below my body. As soon as my legs float up, my descent stops.

At that point, I usually grab a buoy line and descend hand-over-hand. But even during this process, my legs insist on putting me in a sitting position instead of a standing position. I want to be able to cross my ankles and just sink, like everybody else.

Hmm, actually there is something that I forgot to do on my last few dives: I forgot to remove air in the legs of the suit before entering the water. I may have had a fold in the suit near the ankles. Maybe that's why I had trouble descending.

What say you, please? Is leg buoyancy a known property of Henderson Greenprene, or am I making a common mistake somewhere here?

Thank you for your help.

-Bubba

The problem isn't you, it's your instructor. You shouldn't have been certified without being able to control yourself underwater.

There are a bunch of UTD instructors in California. Find one and take an essentials or an extreme scuba makeover. I'm pretty sure one of those can be done in your current kit.

 

[scubaozy]

1. You have to keep your posture, just like you would keep it at the surface. Do not allow your self to become a jelly. In vertical position, your legs should be heavier because they are deeper, tense your leg muscles enough and control your posture.
2. Breathing out means, fully deflating your lungs for 30 seconds
3. Do not inhale until you descent to 10-15 feet, if you must, you breath in but back out immediately, this way you will continue being negatively buoyant
4. After you manage first few feet, your suit will compress, you will be heavy enough
5. Slowly transition from vertical to horizontal, without kicking, if you kick even slightly vertical, you will go back to point one. Transition should be done with posture control.

 

[Angelo Farina]

Honestly, I don’t see the problem. You should be in the prone position while diving. Decending, Ascending, swimming…all prone.

Well, I often descend swimming head down, and ascend swimming head up. As a previous free diver, this looks normal to me.
If descending the legs stay up, that is just perfect: the optimal attitude for swimming down using a good kick...
This insistence of always staying horizontal is quite disturbing to me: one should stay in the position which minimizes drag , allowing to swim with minimum effort.
If you are swimming horizontally, then of course your body should be horizontal. But when swimming up or down, the body should be vertical, either head up or head down.
In my view a BCD is not an elevator, it is just a device to be used for correcting gross buoyancy variations due to the suit compressing with depth and the tank becoming lighter when empty.
Going down or up should be done swimming, while keeping an almost neutral buoyancy thanks to the BCD (or using a low-compressible suit and proper weighting, which makes the usage of the BCD substantially superfluous).

 

[PR_SMITH]

If you have to remove the air from the legs of your wetsuit, then suit is far too big, and allows air to be trapped there. The wetsuit should be a snug fit.