Ascending and Descending in Horizontal Trim

ae3753

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• Nov 17, 2009

• #1

New divers often have a difficult time ascending and descending (and holding stops during ascents and descents). Most of the issue is with buoyancy control, however body position plays an important part.

I feel that the vertical body position, as taught by many OW courses, makes ascents and descents more difficult. To provide an alternate viewpoint, I wrote an article comparing horizontal vs vertical body position for ascents and descents.

Not an original idea (as I was taught horizontal body position by my OW instructor), but this discussion of body position is often missing in OW texts.

How to ascend and descend

Thanks for reading.

 

Blackwood

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• Nov 17, 2009

• #2

Your articles are great, Don. Thanks for sharing.

How do you make your graphics?

 

crd_kats

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• Nov 17, 2009

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Thank you for sharing. Your dedication to instruction is commendable. It makes learning much more fun when the instructor is excited to teach.

 

Ben_ca

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• Nov 17, 2009

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Don,
Another great article. An add-on if I may. A lot of new divers are not sure about the speed of the descent... so a note to mention that you should be able to arrest your descent with relative ease (Advanced diver within 1-2 ft, new diver 4-5 ft?) if you need to. Most problems I've witnessed (ear block, reverse block ect) happened on ascent or descent so a quick pause or stop if need be would be helpful.

Thanks again for helping out our future dive buddies... Keep them coming.

Ben

 

Gombessa

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• Nov 17, 2009

• #5

Don, great article and well-illustrated to boot!

Another thing I would add (and it's easy to get lost in the minutia) about vertical trim on ascents is that you're limited in your ability to descend, since any finning will bring you upwards. From a horizontal profile, you can easily tilt up or down to kick and start moving in whatever direction you need.

 

OP

ae3753

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• Nov 18, 2009

• #6

Thanks for the reading, the feedback, and the additions. They are much appreciated, and will improve the article. I hope to add dissenting opinions too, but that'll have to come later.

Marc, as for the graphics, I made them in Photoshop. I'm not a professional, but if you have an idea for something, drop me a line.

 

ShakaZulu

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• Nov 18, 2009

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Oh, and a BP/W makes is required equipment to ascent/descent horizontally

 

C

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• Nov 18, 2009

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Thanks for the great article, once again! :cool3:

 

fnfalman

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• Nov 18, 2009

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I think that PADI wanted to teach vertical descension because supposedly the diver can equalize easier with the Eustachian (spelling?) tube straightened out and upwardly pointed.

I personally think that vertical descension is stupid because you can't see where you're going, not to mention going down too fast because of lesser hydrodynamic drag. Sure, equalize first and then turn to horizontal body position.

However, I do feel that vertical ascension, at least from the safety stop depth to surface, is a good idea because you can easily turn 360 and look to make sure you're not going to bang into anything. Do a safety stop or deco stop with horizontal body position then as you make the final ascension, turn yourself vertically and go up while looking around to make sure that you're clear to surface.

 

MXGratefulDiver

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• Nov 18, 2009

• #10

fnfalman:

I think that PADI wanted to teach vertical descension because supposedly the diver can equalize easier with the Eustachian (spelling?) tube straightened out and upwardly pointed.

I personally think that vertical descension is stupid because you can't see where you're going, not to mention going down too fast because of lesser hydrodynamic drag. Sure, equalize first and then turn to horizontal body position.

However, I do feel that vertical ascension, at least from the safety stop depth to surface, is a good idea because you can easily turn 360 and look to make sure you're not going to bang into anything. Do a safety stop or deco stop with horizontal body position then as you make the final ascension, turn yourself vertically and go up while looking around to make sure that you're clear to surface.

Click to expand...

I believe that vertical ascents/descents are taught primarily because that's the orientation that we are most familiar with (spending virtually our entire waking life that way), and it's one less thing that a new diver has to get used to. That doesn't make it the best way, but given the "fast track" approach to learning how to dive it's one of many trade-offs (like kneeling on the bottom) that are made in order to get people in the water as quickly as possible.

Effective adaptation to a weightless environment takes time ... and time is the one thing you don't get a whole lot of in most scuba classes.

... Bob (Grateful Diver)