Diving for 2 minutes to 20 feet or 10 feet and coming to the surface

[scubadude223]

No problem, I will try to limit my times doing it.

I can't find a profile on my style of diving.

thanks for the information regarding it.

 

[Doc]

...I just don't know what is safe if I don't do it.

Everything is safe if you don't do it. Easy breezy!

 

[JarrodS]

@ The OP risk is in the numbers...

I believe someone tried to represent it before... when ascending in scuba you are at a greater risk to lung over-expansion injury. Normally when diving you do one ascent and you take your time and do it properly... if you are doing multiple ascents in rapid succession you increase your risk, can become complacent etc.

Complacency is the main risk as I see it. There is no way I would trust myself to do 50-100 ascents over the course of a few hours without screwing up one of them. It only takes one mistake and there are no do-overs.

 

[charlier]

I rarely suggest additional training, but take a freediving class. With depths to 7m of less, with static and dynamic apnea training and proper free dive technique, you should be able to greatly increase your bottom collecting time. Understanding the relations between surface interval and freediving time, you will also be able to safely freedive within a conservative window.

I would freedive that profile, and do it all day every day for infinity. The danger of scuba is lung expansion or embolism, not DCS.

 

[Eric Sedletzky]

I used to this type of diving in Lake Tahoe years ago. I would snorkel along pushing my kayak from behind scanning the bottom. When I saw something of interest I would grab my 30 CF pony with a sling handle and hand hold it and go down to check out what I saw. I've found all sorts of crap, golf balls, tons of fishing gear, sun glasses, cell phones, digital cameras, antique bottles. Depths were never more than 30 feet but normally 15 or 20 feet. As long as you're breathing the whole time and only staying a minute or two I don't see the problem. I also don't see where it would be much different in nitrogen uptake at those very short dive times from freediving. BTW, Freedivers have been known to get bent, it can happen and it's not just a breathing gas at depth phenomenon.
Taboe is also at 6225' elevation so I made sure not to do a lot of that type of activity with the complications of less surface pressure....just to be safe

 

[descent]

... knew a guy who got pretty seriously bent (decompression sickness) when doing commercial inspection of a seawall. They were stupid, they swam up and down like 1 to 25 feet, over and over in cold water for three tanks.. He woke up partially paralyzed. theoretically you can dive all you want between zero and 33 feet, but in reality.. you might want to be a little careful. ...

An infiltration profile is like that. A peek, then a fairly strenuous swim down at 20'-25', then another spy hop. Repeat all day. In shallower parts of the harbor, it's a great way to get a shopping cart in the face.

I never heard of anyone getting bent doing this, not even a joint niggle. I can see how exercise + cold while scanning an entire freaking breakwater in one afternoon might do it.

I do remember that after awhile, lots of people ran into problems clearing or with their sinuses. I saw a couple of king-sized bloody noses. Some dick would always yell "Put a tourniquet around his neck!"

 

[FinnMom]

You should also read about microbubbles and how they create seeds for bubbles to more easily form on subsequent dives. These microbubble seeds also cause the bubbles that form on later dives to be larger than those formed when no/fewer microbubbles were present. Reference: if I remember Deco for Divers correctly.

Ever used one of those home soda making machines? You add gas to the water and everything is just fine. Then when you add some flavoring it provides a seed for bubble formation. Bubbles start to form like crazy as more gas starts to come out of solution. Add flavoring a bit too fast and your mixture will bubble up, out of the bottle and all over everywhere. That's how seeds for bubble formation work.

 

[Eric Sedletzky]

You should also read about microbubbles and how they create seeds for bubbles to more easily form on subsequent dives. These microbubble seeds also cause the bubbles that form on later dives to be larger than those formed when no/fewer microbubbles were present. Reference: if I remember Deco for Divers correctly.

Ever used one of those home soda making machines? You add gas to the water and everything is just fine. Then when you add some flavoring it provides a seed for bubble formation. Bubbles start to form like crazy as more gas starts to come out of solution. Add flavoring a bit too fast and your mixture will bubble up, out of the bottle and all over everywhere. That's how seeds for bubble formation work.

I guess that would be like coming up after a dive then drinking Kool-Aid

 

[Kca3131]

The no deco tables don't start until 35 feet, so you don't need to worry about your nitrogen as long as you haven't been doing other dives within 24 hours. It is safe to come up and down slowly many times as along as you don't hold your breath. However, that isn't the way we plan dives, and why do you need to keep coming up if you are on SCUBA? Just bring a bag to collect.

 

[Jim-SAR]

No problem, I will try to limit my times doing it.

I can't find a profile on my style of diving.

thanks for the information regarding it.

You can't find a profile, because it's commonly called a "saw tooth profile", or a "bounce dive", and they aren't recommended by any agency that I know of. Many people in this thread have answered your question about the risks/safety, and have provided possible alternative methods for accomplishing your tasks, but it seems like you're looking for more information for some reason. Here are some links for you to use/read.

NOAA Diving Manual - Chapter-2 Physics (Downloadable PDF)

NOAA Diving Manual - Chapter-3 Physiology (Downloadable PDF)

Why We Do Not Bounce Dive After Diving in the WKPP



Dive Safe :diver:

---------- Post added July 29th, 2015 at 11:26 AM ----------
(removed duplicate post)