Reasons to take a propulsion/trim/buoyancy class...

[TSandM]

I think you're right; the diver who is perfectly horizontal cannot compensate for not being neutral by swimming up or down. But that also means that the horizontal diver will instantly be AWARE of not being neutral, whereas the head-up diver can swim around negative and not know it, unless he tries to stop.

Trim and buoyancy are intertwined -- UNLESS you are motionless.

 

[dfx]

I've found that if you kick hard enough, neither trim nor buoyancy matter much, you can steer yourself any way you want. It's part of the reason why new divers always seem to be in a hurry to get somewhere, because as soon as they stop kicking, they start going up, down, sideways, etc... This also means that you can be perfectly neutral but totally out of trim, and still swim horizontally, while not being aware of anything being wrong.

 

[guruboy]

Give me two pool sessions if you're a non-diver or one if you're a diver. You won't be perfect, but you'll have the tools to get mostly there in another 10-20 dives.

I've been wanting to visit Key Largo. Might try to take you up on that when I go!

 

[mikeycanuk]

Reminds me of the DM in-training at Rockport last week here in Ontario. What a goof, not sure on the DM instruction but I would have thought buoyancy would have been a requirement . Needless to say this a-hole was burning though air twice the rate we were and was severely over weighted (doggy paddle). Should be in a PADI vid. Both times he was on the instructors octo in no time. I must note he was diving to get hours (for the DM?)/fun. We were doing our Advanced so we got shortchanged, me and my son both surfaced with over 1000psi. I did catch a conversation between him and our instructor, the DM-in training added something like an extra 10lbs but the instructor couldn't get a reason out of him. He also purged 100psi out of my reg thinking it was his (I was next to him on the boat-same regs), he moved our bags, showed up late to the initial briefing, took my gloves which looked nothing like his, crashed into my wife on the surface and just a general goof. The next day they put him with another group and they did something later to upset him but never learned what it was. The group leader put him behind and above the group to learn to watch/practice or whatever part of the DM course he needed to learn. I think someone gave him a pony bottle but this dude needed a hooka system. I half expected him to drown and go missing. no joke.

If this taught me one lesson is that divers like this exist. Given that a live-aboard is too high a risk to take, unless it's just the 3 of us. At least on land we could always decamp to another dive-op!

 

[The Chairman]

The three components: breath control, trim, and amount of weight/air in the BCD all pretty much have to be in place for any one of the three to work in motion.

Well, duh! Of course all three have to be addressed, but you have to get the foundation right (trim) before you build the house. If trim is the foundation then neutral buoyancy is the structure and the weight is the material used to build the house. If you get the foundation right from the start, then everything else becomes far, far easier. Everything. If you build the house first (weight and buoyancy) and then try to get the foundation right, it's going to take a lot, lot longer with all sorts of frustration as you wig wag back and forth. It's just not that hard to do this from the beginning, though I understand that some instructors want to be lazy about it. The first half hour/hour in the pool is all about getting students trimmed out. Once they are are trim, they can stop without having to scull or fuss with their BC. Now all they have to do is to slightly adjust their trim or breathing to go up or down without touching their BC. I suppose you could get the cart before the horse, but why? It's far easier to do it the right way.

But neutral buoyancy can be worked on while the trim is still in process.

You mean like this? That horse looks pretty neutral to me. I bet that's the equine version of the Buddha hover!

Getting them horizontal is great positively buoyant on the surface, but it has the prerequisite of already being neutral once under water, otherwise they are doing pushups to stay off the bottom too often.

Your sentence doesn't make all that much sense. Let me address the part I do understand. My students are allowed to hold themselves off the bottom with one finger. I ask them to pretend to look for a dead spot on the reef and to support themselves with just the one finger on the right hand, while they get their buoyancy set gently with the left hand. Fins, arms, hands, bodies and knees simply aren't allowed on the bottom. They get to use one finger at a time and they get ten chances. No fin pivots for my students either. We work from the top down and not the traditional from the bottom up.

 

[TSandM]

This also means that you can be perfectly neutral but totally out of trim, and still swim horizontally, while not being aware of anything being wrong.

I don't understand this at all. If you are perfectly neutral and out of trim, and you kick, you're going to change depth, depending on whether your fins are aimed up or down. If you are NOT neutral, you can swim with your fins aimed down (or up) and have your net displacement be horizontal, but if you stop kicking, you will sink (or rise). And if you are neutral, why would you be aware of anything being "wrong"? (I'm confused.)

 

[guruboy]

Maybe they like swimming sideways?

 

[aeweems12]

I've been wanting to visit Key Largo. Might try to take you up on that when I go!

Best course you will ever invest in guruboy!

 

[The Chairman]

Best course you will ever invest in guruboy!

Wow! Thanks for the more than kind words! I should point out though, that you did all the work.

 

[FloridaPhil]

Can't wait for my course with NetDoc in Key Largo later this month. As a newly certified diver this is exactly what was looking for. The PADI OW course just about paid lip service to buoyancy and propulsion and trim were not even discussed! So glad I found this thread. Makes total sense.

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