ending a dive

[Thalassamania]

What you do, how you do it and with whom is your decision, all I can tell you is that I do practice free ascents, not on stressful dives and generally not to the surface, but to twenty feet, or so.

 

[sambolino44]

Sounds interesting. I'd like to know more. What depth are you starting from? Does this simulate an out of gas situation? In other words, do you refrain from inhaling until you stabilize at 20 ft? What rate are you ascending at? Is this in a wet suit or a dry suit? Is your BC empty for this? Are you doing this with a buddy? Thanks.

 

[Thalassamania]

Sounds interesting. I'd like to know more. What depth are you starting from? Does this simulate an out of gas situation? In other words, do you refrain from inhaling until you stabilize at 20 ft? What rate are you ascending at? Is this in a wet suit or a dry suit? Is your BC empty for this? Are you doing this with a buddy? Thanks.

Typically in the range of 60 to 120 feet. It simulates not having gas, why you don't have gas is rather irrelevant to what you have to do. I have a buddy, I ascent at 60 FPM to 20 feet, suit doesn't matter ... it's easier in a dry suit. With a dry suit the BC (If I am wearing one) is empty, if I am in a wet suit I usually swim up will the BC takes over and then I use a BC Siphon Technique to control my ascent to 20 feet.

 

[rx7diver]

My buddy and I did some tests to see how far away we could get from each other, simulate running out of air (exhale and pretend you cannot inhale), and get to our buddy, get their attention (the buddy was expecting this), and do an air share. We were very surprised how close we had to be to each other to successfully carry this out without resorting to inhaling from our (supposedly empty) rig. Very surprised. It was a LOT closer than what we thought was a safe distance. I think most divers would also be very surprised at how close you have to be to your buddy for this to work out.

Sambolino,

My open water training (NAUI, 1986) left me with the opposite impression: Even if you're NOT very near your buddy, you have more time than you would think to navigate back to him/her, signal out-of-air, and commence buddy breathing (i.e., passing a single 2nd stage back and forth between the buddy pair). One of our required open water skills reinforced this. Here's the description:

A buddy pair in full cold water gear descends along the slope (northern Arkansas lake, horizontal vis ~20 feet) to ~30 ffw with the instructor and a TA. The instructor signals for one of the divers to remain where he is (the TA remains as well) and for the other diver to lazily swim away along the bottom as might sometimes happen during a real dive. The instructor remains above the swimming diver, out of eyesight. At some point, after the diver has exhaled, the instructor reaches down and removes the swimming diver's mask and 2nd stage, suddenly and without apology. At this point, the swimming diver turns his dive, navigates (using the slope contour) back to his buddy, signals out-of-air, and commences buddy breathing.

At the point the instructor removes the swimming diver's mask and 2nd stage, the instructor dangles his octopus reg in front of the swimming diver. If the swimming diver accepts the dangling reg and breathes off of it, he fails the skill. He now must pass the skill *twice*! Passing the skill is required in order to be certified by the instructor.

The instructor removes the swimming diver's mask and 2nd stage when the swimming diver is ~75 feet (the length of a 25 yd pool) away from his buddy.

The buddy pair is fully briefed about the skill before the skill commences.

I have never heard of a diver NOT passing this skill!


BTW, the divers are well-prepared for this open water skill. Before being allowed to participate in the open water practicum, they must have already passed a pool skill (called the "Underwater Circuit"), which consists of two tanks wearing regs placed at each end of a 25 yd pool, two divers breathing off of the two regs, and a third diver crawling from one tank to the other. When the crawling diver reaches the diver breathing on the tank, he signals out-of-air and begins breathing off the tank while the diver who gave up his tank begins crawling back to the other end of the pool. This "round-robin" circuit continues until each diver has completed 10 lengths.

The divers wear fins and weight belt, but no mask and snorkel. The divers must crawl very slowly and constantly bubble, for each length is supposed to simulate a free ascent from 75 ffw. If a diver—any diver in the trio—completes a length—any single length—in less than 1:15 (simulating a 60 fpm free ascent), then the entire skill must start anew. If any diver fails to bubble sufficiently, then the entire skill must start anew. If any diver surfaces prematurely to breath surface air, the entire skill must start anew. If any diver hyperventilates when breathing off the tank, the entire skill must start anew. A TA Swims directly above the crawling diver for the entire skill.

Needless to say, this is a very long skill, requiring the better part of an hour to complete. Sometimes other TA's must replace emptied tanks with fresh ones during the skill.

By the time the skill is over, the student divers have a real appreciation of just how slow 60 fpm actually is. And for how incredibly far one can travel once one has lost his air supply.


A lot of this stuff is made so much easier with thorough training.

Safe Diving,

rx7diver

 

[Thalassamania]

That's not atypical of early training, and, as you note, was not a big problem for a prepared student.