The passing of Dave Shaw really effected me, one of the most obvious things to me after watching the footage was the laboured breathing which was mentioned briefly by Don Shirley on his commentary of the dive. Ever since first watching the dive in 2019 I said to myself yes the breathing is laboured but I need to know more about the intricacies. This lecture (made complete sense) and has left me feeling a lot better of the cause. Thank you!

this is the kind of stuff that saves lives.

I have stopped diving my LP85 twin set on long bottom swims in a DrySuit and heavy fins in cold water. At 128 feet down on air and reaching a small speed boat wreck I had rapid heart rate and light headedness overcome me. I stayed calm and everything was fine. However, that is a lot of weight to swim 170 yards to see a small boat or anything else. Glad to find this lecture. Learned so much. On a dive like that you go very , very slow, or better yet just go down a line at rest.

I had a CO2 hit recently, and I found my way here researching that terrifying experience. Thanks for the informative and enlightening video. No more exercise at depth for me!

I've had to rescue a dive buddy who got hit hard by CO2 narcosis. We were diving a reef that's in one of the channels in one of the atolls in the Maldives, the current was several knots, and the reef was down at 30 meters. We got dropped off a bit away from the reef and had to fight current to get to it. I went deeper, down to the bottom, near 40 meters, to get under the worst of the current, and made it to the reef without exerting myself too badly, my buddy though, she just power kicked herself to the reef at 30 meters, but when she got there she was out of it, totally dazed, couldn't think, just held on to the reef. I notified the dive master that she had a problem, and called the dive, and in so doing got dragged away by the current, since I let go of the reef to make the sign. I shoot off like a rocket, at this point the current is at least 5-6 knots, and some of it was down current at one point, to the point where I had to fully inflate my BCD to not get sucked down, and then vent it when I get out of the downcurrent. I see that the dive master has left my buddy, but she's still out of it, so I had to swim back down to my buddy and grab her, and assist her ascent. She didn't recovered her faculties until she was at the surface and the reg was out of her mouth. Both me and my buddy are and were scuba instructors, and the dive master screwed up badly on another dive after this as well(he'd swam off at a brisker pace than we cared to go, and just left us behind, boat took an hour and a half to find the two of us at the surface after), tried to blame us, and got fired when we complained.

Depth snobbery accurate and also illuminates dangerous peer pressure in diving.

Thank you for an excellent lecture!

very interesting and informative video! can't believe nobody else commented on this video. thank you DAN and Dr. Simon Mitchell. we need more research like this if we are going to try to overcome issues with CO2, WOB, etc.

Incredible Presentation

this is so good!

Thank you for sharing these lectures. They are incredibly well put together, and I'm learning a lot. I've read that Shaw had a gas density of about 10g/L on his fatal dive. If correct, do you know if there's a reason why the gas was so dense? Logistics?

Excellent explanation Thanks

Thank you, very interesting, informative, and clearly presented material. Would be interested to know why it got downvoted by the people that did so. (As in, did they disagree with the material or some other reason?)

so we need BiPAP for deep dives? what about commercial divers who go deep to do work?