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@tursiops ' reply might have gotten lost in the follow-up discussion about weights, but it bears repeating. The biggest concern with a fast descent rate would be some sort of barotrauma.When I get in the water, I tend to dump all my wing gas and exhale and descend pretty fast. When I get to depth I add gas to the wing and level off. We always worry about rate of ascent for obvious reasons but is there an unsafe descent rate? The only thing I can think of is maybe higher chance of narcosis?
Definitely something to touch on in the pre-dive discussion.You fast descenders: don't leave us behind!
The tables are ALL designed with a certain descent rate. Navy and NOAA tables say not faster than 75 fsw/min (otherwise you'd be at depth and accumulating N2 sooner -- thus longer -- than the tables were designed for). The PADI/DSAT RDP is based on 60 ft/min.I'm curious about the assumption of a certain descent rate and impact on bottom time calculations. It doesn't make sense to me. What if you don't descend to your deepest depth immediately? It seems like the computer would dynamically adjust it's calculations based on your actions in real time as opposed to making assumptions.
Yes, it's not an issue with a functional computer on your wrist.It seems like the computer would dynamically adjust it's calculations based on your actions in real time as opposed to making assumptions.
Yes, for computer users, the computer will adjust, but it can still be an issue. When planning a technical dive, you preplan how much gas you will need, and you carry an appropriate amount (with reserve). In the example I used, you would use more gas than planned on the deepest part of the dive, and you will use more on deco because of your longer deco times. You should have more than enough in your planned reserve, but if you have an emergency that requires that reserve, you may not have enough.Yes, it's not an issue with a functional computer on your wrist.
Those who use tables or pre-planned profiles (even as backup) need to consider any deviation from the various assumptions. Some differences make the plan more conservative, others (like a faster descent rate or a slower ascent when in deco) make it worse.