Read the following article and let me know what you guys think.
http://www.scubadiving.com/training/basic-skills/2006/10/deepest-dive-first-not-anymore
I put lots of faith in my dive computer and do my best to follow everything it tells me to do, but it would be nice if I could dive reverse dive profiles comfortably. Say, hit the 60 and then move out deeper to 100’ if the vis sucks at the 60.
14’ Pamlico 140 Angler w/ rudder
Kayak, SCUBA, or both.
Dan also did a study several years ago and came to the conclusion that it was ok. We dive shallow dives first all the time. Some think that it might even be a better way to dive all together.
You still retain better bottom time doing the deepest dives first. Ideally, you manage your gas to go from HIGHEST partial pressure of 02 to lowest to keep your bottom time long. If you have the mix to make every dive to exactly 1.4-1.65pp02, then the depth changes don’t matter at all. It just so happens that (as most of us do) we have three bottles blended at 34-32%, and do the dives in 110’ first, followed by dives in 60-70’, it works works better than the other way around since the PP02 of your shallow dives is so much less than the deep ones. If you did dive 1 to 60’, breathing 44%ish (puts you at 1.38pp02), then followed it with two dives in 111’ (each breathing 32% - so again, 1.40pp02), then doing the shallow dive first won’t make a difference. Unfortunately, medical grade breathing oxygen is expensive, and that would just about double the cost of your back gas just to dive the 60 first? Not worth it to me! Solution: get a re-breather.
If you have multiple experienced divers then just alternate bouncing to limit your no2 exposure. If the bounce diver hits bottom and feels like the others should dive then throw a lift bag as a notice to drop. Use this method for finding viz or fish. You can cover a lot of ground and find new productive spots in a quick and efficient manner.
Stephen Goldfinch
“Sleep When You’re Dead!”
Also,
If you’re not already, get trained in advanced nitrox and dive with deco tanks. Switching from 30% to 50 to 75% can seriously decrease your deco obligations. Most of this will do away with the worries of where to start and where to finish.
Stephen Goldfinch
“Sleep When You’re Dead!”
quote:
Originally posted by yellabirdIf you have multiple experienced divers then just alternate bouncing to limit your no2 exposure. If the bounce diver hits bottom and feels like the others should dive then throw a lift bag as a notice to drop. Use this method for finding viz or fish. You can cover a lot of ground and find new productive spots in a quick and efficient manner.
Stephen Goldfinch
“Sleep When You’re Dead!”
We have an underwater weighted camera on 150’ of cable that sends an infrared video feed to a TV in the cabin. This helps us out with checking out the viz in shallow.
14’ Pamlico 140 Angler w/ rudder
Kayak, SCUBA, or both.
We’ve tried the cameras but never get the results we’re looking for. You just can’t get a good perspective. There’s no substitute for a set of human eyes.
Stephen Goldfinch
“Sleep When You’re Dead!”