Trim Problem

[mikemill]

B.S. ankle weights are for the people that never learned to dive a drysuit the correct way. Not only do they tire you out faster they aren't necessary. Focus your additional weight around your center of gravity (waist) and adjust your tank, the rest you can correct with body positioning and practice. I went through being "foot" light when I first started diving doubles. It was resolved with a 4lb tail weight on the bottom band bolt and readjusting my body positioning. I don't know what gear your diving but a weighted STA might be the answer instead of ankle weights.

Ankle weights are an equipment solution to a training problem.

What is the difference between ankle weights and "heavier" fins?

Soakedlontra: I also dive force fins which I absolutely love. During my Essentials class with Don (ae3753) I also tried a pair of paddles and didn't like them. During the same class the floatly feet issue got me also and I did resort to ankle weights. By the end I didn't need them but they were a great interim solution.

Things that I have found help:
Frog kicking. While the FF isn't the best at it I have found that it does it adequately well for the speed I want to go. If I need speed I switch to flutter and then go back to frog. The frog kick just seems to keep me in better trim.

Really do look at your undergarments. I came to realize that I wasn't wearing enough under my drysuit and I ended up keeping too much air in the suit to keep warm. More air means more expansion in that one or two foot ascent when you get out of trim. I have added more undergarments and am having a much easier time.

 

[MXGratefulDiver]

Ankle weights are an equipment solution to a training problem.

Not necessarily. I am not a big fan of ankle weights ... but I have had a couple students (one in particular) who benefitted from their use.

Sorry Street Doctor ... I'm not a big fan of dogma either. Everybody's different, and although I think there are almost always better alternatives, I have found them to be a viable solution in some (rare) cases.

... Bob (Grateful Diver)

 

[Soakedlontra]

What is the difference between ankle weights and "heavier" fins?

Soakedlontra: I also dive force fins which I absolutely love. During my Essentials class with Don (ae3753) I also tried a pair of paddles and didn't like them. During the same class the floatly feet issue got me also and I did resort to ankle weights. By the end I didn't need them but they were a great interim solution.

Things that I have found help:
Frog kicking. While the FF isn't the best at it I have found that it does it adequately well for the speed I want to go. If I need speed I switch to flutter and then go back to frog. The frog kick just seems to keep me in better trim.

Really do look at your undergarments. I came to realize that I wasn't wearing enough under my drysuit and I ended up keeping too much air in the suit to keep warm. More air means more expansion in that one or two foot ascent when you get out of trim. I have added more undergarments and am having a much easier time.

I have never had a big problem in frog kicking. Do I do it in the way that it is 'supposed' to be? I don't know. The only thing I know is that I can move forward and I feel stable. (Back kicking is still a headache for me but I haven't practiced it that much either so I shouldn't complain).

The fundamental problem is not finning but standing still horizontal, neutrally buoyant. The ankle weights seem to help me, right now, to achieve that.But this is not the end of the story. I have more adjustment to do with the weights and get a better understanding on how this bloody air in the dry suit works and interacts witht the undergarment. For instance a couple of days ago even if I was wearing the supposedly super warm Whites MK3 I was COLD throughout the dive (max depth 37fsw!!!.)

When I switched diving dry it seemed that I had stepped into 'hell'! At first nothing seemed to be working any more. After 52 dives I feel I am slowly moving from hell to purgatory...

 

[TSandM]

Remember that staying warm in a drysuit is in part related to how much gas you run in the suit. If you are diving very squeezed (as a lot of us did when we started with a dry suit, to make managing buoyancy a little easier) the undergarment is compressed and doesn't insulate nearly as well. As you gain facility with the suit and can run a little more gas in it safely, it will be warmer.

But the other thing is that, as you get better, you move a lot less, and you get colder! And you're like me -- you have almost no "native insulation". I've learned the principles of maximizing thermal units: Do not waste any thermal units on shore. No wandering around in a T-shirt and jeans until you're chilled. I go to the dive site IN my undergarments unless the weather is just plain hot. If the wind is blowing, I add a hat and a windbreaking coat OVER the undergarments until I've reached the point where I can put on my drysuit -- and even then, the coat may go over the drysuit. No thermal units left on shore!

Minimize in-water time before diving. Don't lose thermal units in the shallows. Do the dive plan and the gear checks that you can do on land. Don't get in the water and wait for anybody -- be the last one wet.

Wear a thick, well-fitted hood. It makes a difference. I dove a Harvey's hood for the first two years that, in retrospect, didn't fit very well. But I didn't know how a hood was supposed to fit. The one I have now lets in so little water that I'm sometimes a couple minutes into the dive before I feel the first trickle of cold on my scalp.

Keep your feet and hands warm. Good insulation on the feet, and dry gloves. Don't lose thermal units through your extremities.

Fix any and all leaks promptly. Being wet is the worst waste of thermal units!

Argon makes a difference. I'm sorry, the papers say it doesn't, but I've done my own experiments and even if it's a placebo effect, it's worth $3 a dive to me to get it.

And even with all that, Puget Sound is cold. My dives are rarely NDL limited, almost never gas limited, but quite often limited by running out of thermal units (I don't dive thirds on them, though!)

 

[boulderjohn]

But the other thing is that, as you get better, you move a lot less, and you get colder!

This has been on my mind recently.

I read a study that suggested a factor in DCS on deco dives may be related to this. During the working portion of a dive, you are active and relatively warm. Your blood is circulating freely, and you are very efficient in the process of on-gassing. During decompression stops the protocol is to be relatively motionless, staring at your teammates as time passes slowly. You are not active, and you are getting cold. Your circulation is compromised, and you become inefficient at off-gassing.

Thus, the last time I did deco stops, I started swimming around, mostly just to keep things circulating. Fortunately, I had told the team ahead of time what I was doing so they weren't wondering, and a couple did the same.

 

[Soakedlontra]

Remember that staying warm in a drysuit is in part related to how much gas you run in the suit. If you are diving very squeezed (as a lot of us did when we started with a dry suit, to make managing buoyancy a little easier) the undergarment is compressed and doesn't insulate nearly as well. As you gain facility with the suit and can run a little more gas in it safely, it will be warmer.

But the other thing is that, as you get better, you move a lot less, and you get colder! And you're like me -- you have almost no "native insulation". I've learned the principles of maximizing thermal units: Do not waste any thermal units on shore. No wandering around in a T-shirt and jeans until you're chilled. I go to the dive site IN my undergarments unless the weather is just plain hot. If the wind is blowing, I add a hat and a windbreaking coat OVER the undergarments until I've reached the point where I can put on my drysuit -- and even then, the coat may go over the drysuit. No thermal units left on shore!

Minimize in-water time before diving. Don't lose thermal units in the shallows. Do the dive plan and the gear checks that you can do on land. Don't get in the water and wait for anybody -- be the last one wet.

Wear a thick, well-fitted hood. It makes a difference. I dove a Harvey's hood for the first two years that, in retrospect, didn't fit very well. But I didn't know how a hood was supposed to fit. The one I have now lets in so little water that I'm sometimes a couple minutes into the dive before I feel the first trickle of cold on my scalp.

Keep your feet and hands warm. Good insulation on the feet, and dry gloves. Don't lose thermal units through your extremities.

Fix any and all leaks promptly. Being wet is the worst waste of thermal units!

Argon makes a difference. I'm sorry, the papers say it doesn't, but I've done my own experiments and even if it's a placebo effect, it's worth $3 a dive to me to get it.

And even with all that, Puget Sound is cold. My dives are rarely NDL limited, almost never gas limited, but quite often limited by running out of thermal units (I don't dive thirds on them, though!)

I know I go off the topic a bit. I usually get overheated in the Whites MK3. Now that the air temperature is going down is not as bad. The feet and hands are still cold. I haven't yet experienced a dive when I felt them warm (so much warm dry suit diving!). I have to keep experiment with different liners and maybe switch to already insulated dry gloves and with other kind of socks...Never ending battle!

I am beginning to think that maybe a shell dry suit with detached rock boots is not suitable for me!

 

[Bubbletrubble]

I read a study that suggested a factor in DCS on deco dives may be related to this. During the working portion of a dive, you are active and relatively warm. Your blood is circulating freely, and you are very efficient in the process of on-gassing. During decompression stops the protocol is to be relatively motionless, staring at your teammates as time passes slowly. You are not active, and you are getting cold. Your circulation is compromised, and you become inefficient at off-gassing.

Thus, the last time I did deco stops, I started swimming around, mostly just to keep things circulating. Fortunately, I had told the team ahead of time what I was doing so they weren't wondering, and a couple did the same.

@boulderjohn: At the risk of a thread hi-jack...Have you read this commentary on the relationship between exercise and DCS? It makes reference to a primary article showing that a 40 min workout scheduled 24 hrs prior to diving decreases bubble load, possibly by mitigating bubble nucleation. I found the authors' discussion of the potential involvement of nitric oxide in DCS pathogenesis very interesting, too.

Dervay et al. showed that exercise prior to decompression increased venous gas emboli (VGE). Interestingly, as the interval between exercise and decompression lengthened, VGE decreased. After taking a look at the methodology used in this study, you might want to re-evaluate your exertion level during deco stops.

Based on what I've read, you probably shouldn't be purposefully exerting yourself too much during or after a dive since doing so could increase bubble load. Just be sure to do a reasonably good workout 24 hrs before.

 

[TSandM]

A shell suit with detached boots is not suitable for what reason?

If you're thinking about getting cold, I tried a compressed neoprene suit and it didn't make much difference, but it was a lot harder to get in and out of, and dried very slowly.

If it's the trim issue, that is solvable either way, and what you are using on your feet makes very little difference.

 

[boulderjohn]

@boulderjohn:

Based on what I've read, you probably shouldn't be purposefully exerting yourself too much during or after a dive since doing so could increase bubble load. Just be sure to do a reasonably good workout 24 hrs before.

Thanks. I am not talking about vigorous exercise, though. I am talking about gentle finning, just enough to keep things going.

 

[Bubbletrubble]

Thanks. I am not talking about vigorous exercise, though. I am talking about gentle finning, just enough to keep things going.

Ah. OK. Then the abstract from this study would seem to support your practices.