horizontal decent

[cadet diver]

What is the advantage of doing horizontal decents like shown on 5th dimension's webpage?

http://www.fifthd.com/divestore/classes/tech.html

[NetDoc]

10) You get the see the dive site unfold below you.

9) You are already in the proper attitude when you arrive at the bottom.

8) It slows my depth defying descents a tad (students can keep up).

7) Greater stability as I descend.

6) I have greater mobility to turn.

5) It's easier for my buddies to track me as I descend.

4) It's easier and quicker to equalize my eustachion tubes.

3) It keeps me from getting vertigo.

2) Makes it easier to spot items of interest on the bottom on descent.

1) It's fun playing "skydiver"!!!

[divrnr]

Netdoc, I agree especially #1!!! Do a horizontal decent in clear water to 120fsw! Awesome:bounce:

[jonnythan]

NetDoc once bubbled...
10) You get the see the dive site unfold below you.

9) You are already in the proper attitude when you arrive at the bottom.

8) It slows my depth defying descents a tad (students can keep up).

7) Greater stability as I descend.

6) I have greater mobility to turn.

5) It's easier for my buddies to track me as I descend.

4) It's easier and quicker to equalize my eustachion tubes.

3) It keeps me from getting vertigo.

2) Makes it easier to spot items of interest on the bottom on descent.

1) It's fun playing "skydiver"!!!

You left out "keeps me from running into the bottom with my fins and silting out the site immediately" ;)

[jbd]

to see what I'm descending to even if its just my depth guage. When I get to the depth I want if I'm horizontal then I'm ready to take off in whatever direction I wish to go.

Also when I watch people do feet first descents(and this used to happen to me) it seems as though the resistance from the fins would tend to push the diver over backwards which results in all kind of arm and leg motion to remain vertical. Burns up a bunch of air for no useful reason. I eventually was able to descend feet first but then my feet would be near the bottom and stuff would get stirred up just getting into a horizontal position to start off.

Now my weights are placed so that when I leave the surface I automatically rotate to a horizontal attitude without any effort on my part what so ever. Just seems to make diving so much easier.

[Scubaroo]

Expanding on NetDoc's point 7 (great list BTW), if you do a vertical descent, the drag on your fins can force your feet and legs to rise in front of you, and you end up descending butt first - and crashing into the seafloor is a no no - especially if there are sea urchins about!!! Not to mention it screws the visibility and looks terrible.

Plus you risk descending tank first onto another diver's head - seen it before, especially when boat diving. Horizontal descents let you see where you're going and stay off the bottom.

[jbd]

when I started typing my response there were no responses. I guess I type slow;)

[cadet diver]

Is there any safety reason not to do a head first decent finning the way down? I like to drop to depth as fast as possible to not waste air.

[Spectre]

NetDoc once bubbled...
1) It's fun playing "skydiver"!!!

I always feel like that scene in Mission Impossible where the descent is aborted inches before touching the floor! [I think it was mission impossible... ] :)

To add one... much easier to stay on your mark when descending in current.

[Scubaroo]

It's not a race! Plus if you descend too quickly, what happens if you have trouble equalising? Horizontal descents allow you to "flare out" your arms and legs to arrest your descent rate, so you can stop and prevent ear damage if equalisation is difficult. The air saved during a "power descent" versus a horizontal descent would be insignificant compared to air you can save elsewhere on the dive through other things like streamlining, trim, bouyancy control, etc.

[Divesherpa]

Hey Cadet,
Head first kicking is only necessary in very strong current while drifting to hit a wreck. I descend like that anytime the surface is ripping unless I'm doing the superman off a descent line.

[AquaTec]

any thoughts on the speed of descent

30 ft/min ~ 100 + ft/min

include pro or cons with your thoughts

posissioning, NetDoc nailed it

[Jonathan]

head first and kicking is also useful when you drop something like a torch - yes experience talking, not advisable though!!

"Sky Diving" in a ripping current is the best, especially on a long drop in good viz....

[cadet diver]

I have finned to 200 without a problem before. I am not sure I see any reason not to, as long as your buddy is with you, why not?

[NetDoc]

and NAUI uses it as their max as well. 75fpm!!!

While there are no reasons given, I have heard that the onset of narcosis can be premature on a quick descent. I have no data or study to prove this, as I have only heard it from one doctor. Also the effects of inertia will be present, possibly driving you into the bottom if you try to slow at the last minute.

While I have gone considerably faster than this on occasion (free descent in a ripping current trying to find a wreck) I do not see the need to "conserve air" by consuming it. Relaxed ALWAYS saves more air than excersize. You would probably conserve more air by chilling out and letting gravity do it's thing, than by exerting yourself to hasten things along. Less work ALWAYS means more air!!!

[cadet diver]

Well at least its worth knowing and using various techniques, thanks for answering my questions. I will probably still race to the bottom when not leading dives, but I will definately give this horizontal decent business a try.

[Jonathan]

my chase for a torch the problem was I was pushing it to catch the torch so ended up hyper ventilating - took a while to get myself back together after that....

[Cave Diver]

Jonathan once bubbled...
my chase for a torch the problem was I was pushing it to catch the torch so ended up hyper ventilating - took a while to get myself back together after that....

Did you at least catch it? Or did you get yourself all worked up over nothing?

[AquaTec]

NetDoc once bubbled...
and NAUI uses it as their max as well. 75fpm!!!

While there are no reasons given, I have heard that the onset of narcosis can be premature on a quick descent. I have no data or study to prove this, as I have only heard it from one doctor. Also the effects of inertia will be present, possibly driving you into the bottom if you try to slow at the last minute.

I can attest to the onset of narcosis with a rapid descent.
say on a 200 ft dive on air [i know, i know, don't start the air thing] at about 75 - 100 feet per minute narcosis hits my like a sledge hammer at 180 feet, [shallower is not a problem]
how ever a rapid descent does not bother my buddy at all.

now if we descend slow and steady i can stay quite a while with out having any obviouse symtoms of narcosis, however with my buddy the longer he stays at dapth the worse he gets.

the inertia thing could also be a factor if there is a bottom. i do some blue water diving, [dives where you are in the middle of the ocean and there is no bottom] this diving is for a specific reason and we descend fairly quickly - about 100 feet/ min. as timing is of the essence

in one perticular case i was to meet my buddy at 300 feet, he was on a rebreather, and went early to perform his task, i then descended down as the videoagrapher, my plan was to shoot to the bottom and start hitting the brakes when i saw his lights as i was videoing on the way down. well guess what, he was hanging out there with out his light on, just drifting along with the line, well i blew right by him. seeing him i hit the brakes and it took me about 50 feet to stop. if there had been a bottom i would have been planted deep in it. [wel not really, as i would have used a different plan]. now i mount a depth gauge onto the video housing for refference.

[diverberr]

AquaTec once bubbled...
any thoughts on the speed of descent

30 ft/min ~ 100 + ft/min

include pro or cons with your thoughts

posissioning, NetDoc nailed it


I usually descend about 100' per minute. It gets me on the wreck quickly. And I can still do it while staying horizontal. I stop at around 20' on the way down to do my equipment check, then a fast descent to the wreck.

I will however, use a slower descent rate when doing deep air dives, to avoid a rapid onset of narcosis.

And I definitely have to agree with Netdoc's top ten list.

[Lost Yooper]

I used to fly down the line all the time on air, well inexcess of 100'/min. What happens is that you'll take one (maybe two) long continuous breath all the way down, which feels kinda cool, but allows CO2 to build up badly and you get nailed by the highly narcotic CO2.

CO2 is bad stuff, and it's narcotic effects are not talked about a lot.

Mike

[Divesherpa]

Yoop,
I'm not a huge air fan, but I see why you are so anti-air.
You have not always been very knowledgeable about diving. I haven't either.
Glad we lived through it.

Cheers and safe (non air) diving