Feeling like a blimp
- Thread starter jehle
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I will add something that kept nagging at me. Most people replying here are nestors and there's a problem with nestors - they forgot how it is to be a noobie. 
I am a noobie and therefore I remember very well what happens then.
One of the things that affected one of us horribly in the first 5 hours was the fins.
My wife had a set of fins she kept from our "fire extinguisher tank filled with air on the back" days. They served her very well in the OC days and the profile and time/speeds we were doing.
I was using the stiff version of Quattros and wasn't affected.
During the second MOD1 course dive our instructor told her "you need to change your fins, you're slapping your own heels and you're out of control half of the time".
The problem with "resort dipper" fins is that they're soft and optimised for low energy slow speed movement.
What it means is typically they store a lot of elastic energy for later in the stroke (which is going to bite you on the CCR) and have a very shallow limit on hard output.
Because of high drag and high mass - you put up to triple energy into a stroke when diving with a CCR.
That puts soft/resort fins way out of their zone and not only will make you lose energy by inefficiency - it will confuse and destabilise you by releasing it later and when you don't need it.
I think you had plenty enough muscle power to chase the kids on bikes - but it's possible the fins were "failing" you.
The best fins we have are S-Tek, but they're absurdly expensive (I still feel bad about getting them as a gift).
Any proper "rocket" tec fins should make a huge difference in both handling and speed (if you don't have them already).
Try proper stiff tec fins out, you may be surprised.
Just my 5 cents.
I am a noobie and therefore I remember very well what happens then. One of the things that affected one of us horribly in the first 5 hours was the fins.
My wife had a set of fins she kept from our "fire extinguisher tank filled with air on the back" days. They served her very well in the OC days and the profile and time/speeds we were doing.
I was using the stiff version of Quattros and wasn't affected.
During the second MOD1 course dive our instructor told her "you need to change your fins, you're slapping your own heels and you're out of control half of the time".
The problem with "resort dipper" fins is that they're soft and optimised for low energy slow speed movement.
What it means is typically they store a lot of elastic energy for later in the stroke (which is going to bite you on the CCR) and have a very shallow limit on hard output.
Because of high drag and high mass - you put up to triple energy into a stroke when diving with a CCR.
That puts soft/resort fins way out of their zone and not only will make you lose energy by inefficiency - it will confuse and destabilise you by releasing it later and when you don't need it.
I think you had plenty enough muscle power to chase the kids on bikes - but it's possible the fins were "failing" you.
The best fins we have are S-Tek, but they're absurdly expensive (I still feel bad about getting them as a gift).
Any proper "rocket" tec fins should make a huge difference in both handling and speed (if you don't have them already).
Try proper stiff tec fins out, you may be surprised.
Just my 5 cents.
Oh - and fins or no fins - don't chase kids on bikes - you're riding a limo.
mr_v
Contributor
Too much to unpack here. What does your trim look like? Pics? Videos? What kick do you use?
Why? I'm not a CCR diver, but I have noticed several decent/good divers go from diving flat on OC to a knee down trim on CC, and it's rare to see a CCR diver with "good trim". Why is that? I would think that having good trim would be just as important, if not more, on CC with increased drag etc. Also as one of the ways you make small depth adjustments is simply swimming up/down since you can't use the lungs. And if the trim even affects the ability to use fundamental techniques such as backfinning, what's the justification for the knee-down trim? Is it just that much harder to trim out that people give up? Are there any reasons why knee down trim would be advantageous? It's a genuine question, since I don't know...
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It's not a streamlining thing.
Because the position of the CL mandates that you keep it close to the hydrostatic depth of your lungs. Some units force you to "wheelie" torso up - so the CL is then at the same depth as your lungs. In flat trim it will be above your lungs and easy to exhale, but harder to inhale. The Revo, the RB80 and the SF2 are all units that tend to promote a torso up position in particular. The knees naturally end up dropping when your torso is 15-20 degrees or more from truly prone.
DiveLikeAMuppet
Contributor
Many things.
Some of the problem is just skill and quality of training - I know few people who dive AP Inspo in good trim, most don’t because the the unit is tricky to trim and training is sh*t, at least in the UK (AP is the chosen unit of the local club system, which killed most commercial training with predictable results).
Some divers just stop caring.
Part of the problem is work of breathing - you don’t want extreme 0 degrees flat trim with back mounted counterlungs. You don’t want absolutely flat trim with OC anyway due to situational awareness, e.g. “cave” trim would be 15 degrees. Also if you go head-down, a lot of the goop / lung butter in the loop and lungs flows back to your DSV/BOV. In cold water, you drool quite a lot.
I tend to dive my JJ at about 15-30 degrees up (probably closer to 15, so maybe too flat for CCR) in stock configuration. I also predominantly use my drysuit for buoyancy on CCR. That works … mostly, with acceptable work of breathing, finning technique etc.
Generally absolutely no issues with backfinning at depth or in overhead. The config becomes a bit unstable at shallow stops after deep dives - you might have pretty floaty deep bailouts, a considerable gas bubble in the suit with thick undergarments, loop volume might not be optimal because you are off gassing into the loop. In my case, I tend(ed) to end up somewhat head down on the shallowest stop, 5 to -5 degrees with some gas in my feet, when I started diving CCR. Backfinning would pull me ever so slightly up, which would expand all the gas in the loop and suit even more, making me even more unstable and head down … I’m now considerably more aware of the various gas bubbles so backfinning is less of a problem but it’s still not as “agile” as OC.
DiveLikeAMuppet
Contributor
By sidemount you mean widemount CCRs like Kiss or Gemini? Because true sidemounts like Liberty or FX CCRs are actually really sensitive to trim.
With chest mount you probably don’t want to be super flat either if diving with back mounted dil.
Widemount units have their own issues for cold water, especially deeper.
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