Tigerman
Contributor
In the pic on your profile, your hips does seem to be lower than your shoulders...
And your hip being slightly lower than your shoulder does not mean your knees cant be bent upwards.
First Dry Dive...air in legs......
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And your hip being slightly lower than your shoulder does not mean your knees cant be bent upwards.
I only dive in a drysuit, be it in 80 degree water or 40 degree water...and this is how I dive in my drysuits.
1) Use your BC for buoyancy and use the drysuit to offset squeeze. Your drysuit should be snug around you, but not to where it hurts. The goal is to keep the air volume to a minimum.
Using your drysuit only for buoyancy is not practical as you will have a much larger volume of air to contend with and this is what you dont want...although you will be a tad warmer.
2) Ankle weights and changing your position to a more head up stance in the water are all common techniques/equipment for the new drysuit diver...but with more experience you will find you don't need to do this.
If air went to your feet and this caused you to float up something is not right. You should be able to position yourself anyway in the water column and not cause a runaway ascent. Sounds like you were positive to begin with and probably with too much air in the drysuit....when above 20 feet this could be an issue like you experienced.
I went through the same headaches the first 0-30 dives on my drysuit...experience is everything as long as you strive to become better. In the end, do what makes you more comfortable.
J
1) Use your BC for buoyancy and use the drysuit to offset squeeze. Your drysuit should be snug around you, but not to where it hurts. The goal is to keep the air volume to a minimum.
Using your drysuit only for buoyancy is not practical as you will have a much larger volume of air to contend with and this is what you dont want...although you will be a tad warmer.
2) Ankle weights and changing your position to a more head up stance in the water are all common techniques/equipment for the new drysuit diver...but with more experience you will find you don't need to do this.
If air went to your feet and this caused you to float up something is not right. You should be able to position yourself anyway in the water column and not cause a runaway ascent. Sounds like you were positive to begin with and probably with too much air in the drysuit....when above 20 feet this could be an issue like you experienced.
I went through the same headaches the first 0-30 dives on my drysuit...experience is everything as long as you strive to become better. In the end, do what makes you more comfortable.
J
Jet Fins work as a counter-balance somewhat to a backplate. Without a BP you probably wouldn't like the effect that Jet Fins have. I say this only because before I switched to a BP (and Jet Fins) I tried Jet Fins and didn't like them because they dragged my feet down. Once I got a BP I tried them again and didn't have that problem.
I personally think there are much better solutions than ankle weights. Proper fitting boots or fin keepers as a temp solution are better in my opinion.
Wanna sell the Slipstreams? PM me if want to part with them and they're XL!
Seriously... :blinking:
Not a difficult concept at all. The concept that DOES appear to be difficult to grasp is that Jets fins are "gear that happens to be negatively buoyant" which is different than "weight." If you need heavier fins, I have no problem swapping Slipstreams out for Jets if it helps trim you out.
What I do think is problematic is allowing a fixable problem ("air in the legs") to continue unabated. If it's a skill/experience issue fix it by diving and proper instruction. If it's a drysuit design/cut issue get a new suit that fits better, or if that's not an option fix it with gaiters.
However you go about it: Treat the problem, not the symptom.
Just one little additional thought: Your profile lists a weight-integrated BC. I don't know how you're distributing your weight, but an integrated BC that puts your weight in just the right place for horizontal trim while diving wet may hold the weight too far up your body when diving dry. (You're adding an additional bubble spread all the way to your feet, after all.)
If you have all your weight in the BC, and if the BC holds the weight above the level a weight belt would hold it, moving weight (some, all, whatever) to a weight belt may redistribute your weight to better match your buoyancy. It's just another variable you can toss at the simple physics (as opposed to the rabid philosophies) of trim.
And just because this thread, like many others, reminds me of it so, I now direct your attention to one of my favorite stories... about popovers. (By the Great Doctor, I predict you will enjoy it.)
If you have all your weight in the BC, and if the BC holds the weight above the level a weight belt would hold it, moving weight (some, all, whatever) to a weight belt may redistribute your weight to better match your buoyancy. It's just another variable you can toss at the simple physics (as opposed to the rabid philosophies) of trim.
And just because this thread, like many others, reminds me of it so, I now direct your attention to one of my favorite stories... about popovers. (By the Great Doctor, I predict you will enjoy it.)
cinder4320
Contributor
Yep...not in trim, not horizontal at all. I'm also in open water colorful gear, a wetsuit, and not using a long hose nor backplate/wing in that picture. Its an old picture. If I dove like that now I wouldn't be in a cave!
That was a horrible picture! Thanks for the reminder that the old gear config., bad trim, pics still exist.
Miranda
Josh, you're an excellent observer and reporter, and there's plenty of good advice in this thread to try.
After a few more drysuit dives, I'm sure you'll solve the "problem"!
Aside from practicing a bit more, I'd recommend you get your weighting at least up to the minimum. (The minimum needed to be neutral with an empty tank and empty bcd.)
Then see what trim issues you still might have. My guess is they will become less prominent, as you will have more weight on and more air in the torso to start with and your swimming trim won't be "fins up, head down", since you won't need to fin against positive buoyancy. You'll have some normal shifting of air, but it's usually quite manageable.
If you still have a problem, try other things. You will find a combination that works better, and it won't take long!
I tend to look at such problems more broadly and that seems to open up more solutions to consider.
The OP's trim issue might have multiple causes including:
- air shifting too quickly into the legs (baggy suit, thin insulation, porous insulation)
- not enough air remaining in the torso (same causes as above, plus tight bcd straps or possibly tight torso fit or underweighting and insufficient air in the suit)
- the shifting air finds a large pocket in the legs (suit fit)
- weight-trim issues (light fins, location of weight belt and/or tank, etc)
- underweighting leading to a head-down finning position which allows time for a large amount of air to shift
I just love when Reason trumps Dogma!
Thank you again!
For the OP, let me just tell you there is probably more than one way to deal with your issue.
I say that because unlike most drysuit divers, I:
- use only my drysuit for buoyancy control, hence have more air in the suit
- wear about 5 lbs of "excess" lead
- wear ankle weights
- wear extra insulation, including a fleece chest pad
- wear significantly more lead as a result
In fact, to snap a photo or probe under a rock, I can up-end vertically, hold that position for quite a while, then return easily to normal trim.
Although it's blasphemous, my apparently non-standard configuration and techniques work well. There must be something wrong....
I'm confident you'll find several solutions to choose from.
Dave C
While I generally stick with using only the suit for bouyancy control, that is because I use a clx 450 and am therefor only compensating for the compression of the airspace in the suit. In a 6.5 neo suit you will neet to compensate for the internal space and the material compression. This could result in an excessively large air bubble in the suit (which will, by necessity get larger as you go deeper), so with this type of suit I would recommend the equalize suit for comfort use BC for bouyancy method. This will reduce the size of the bubble in the suit, and may solve the problem all by itself. A slight change in body positioning may also help. While staying in good overall horizontal trim, drop the knees slightly below the centerline of the body then raise the feet slightly above the centerline. This generally prevents air from going past the knees.
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