FPDocMatt
Contributor
A few people today were swimming during the surface interval. One person dropped something and swam to the bottom to get it. It was probably 15 feet. He wanted to know how deep it was, so swam back to the boat and picked up his computer.
Someone on the boat said that's not a good idea, because the computer will think he's done another dive. That is, the computer won't realize he wasn't breathing from a high-pressure tank.
I thought this made sense. But then someone said it's also not a good idea to free dive during the surface interval, because you will take on more nitrogen.
Since you're not breathing air at a higher pressure than one atmosphere, I wondered how you would take on more nitrogen. He replied that the higher pressure at that depth will cause you to absorb more nitrogen from that breath than you would if you had held your breath for the same amount of time at the surface.
This also makes sense, but it's not as clear to me.
So I asked, "Do you mean a free diver can get the bends?" He said no, because you're only down there for 5 minutes or less.
Anyway, it sort of makes sense, but I'm still confused. Any clarifying insights would be appreciated.
Someone on the boat said that's not a good idea, because the computer will think he's done another dive. That is, the computer won't realize he wasn't breathing from a high-pressure tank.
I thought this made sense. But then someone said it's also not a good idea to free dive during the surface interval, because you will take on more nitrogen.
Since you're not breathing air at a higher pressure than one atmosphere, I wondered how you would take on more nitrogen. He replied that the higher pressure at that depth will cause you to absorb more nitrogen from that breath than you would if you had held your breath for the same amount of time at the surface.
This also makes sense, but it's not as clear to me.
So I asked, "Do you mean a free diver can get the bends?" He said no, because you're only down there for 5 minutes or less.
Anyway, it sort of makes sense, but I'm still confused. Any clarifying insights would be appreciated.