darksquid:
Down in Costa Rica earlier this year I met two women who dive w/o a watch or dive computer. They both use SPGs exclusively -- when out of/low on air, they ascend. I was shocked because we were doing repetitive and multiday dives to serious depths (80-90'). They seemed TOTALLY unconcerned and said they don't even consult their tables.
I haven't been diving that much, so I have no idea if this is common or I just randomly met two wreckless people at once (and btw they didn't know each other prior to us diving together, so it's not like they were a 'deluded buddy team').
What do the more experienced folks here think -- you see this much?
Well, I guess it comes down to SAC rate. Mine is good enough that I would need at least a BT to make sure I did not hit my NDL. Jupiter is an example of a site where the profile is flat, and I could dive with a BT, but I'd want to make sure I did not exceed 40 minutes on Nitrox 36.
Diving is a risk. Anything that minimizes that risk is IMO essential equipment. If I were diving shallow reefs all the time, I'd not worry much as the NDL's are so huge that you will get kicked off the boat if you can sip air, so some sort of BT is necessary so you don't exceed the maximum dive plan.
I can think of no logical reason NOT to have at LEAST a BT even if it's nothing more than a watch. I use a computer and a Citizen Aquamaster. That can act as my primary and backup BT, and depth guage, as well as the computer functions that provide multi-level dive tables measured during the dive. I still don't completely trust the computer, and make sure I know how long I want to be at depth.
I check the dive tables for whatever mix I'm diving. If doing a flat profile it's easy. Without a depth guage, and BT, I'm not sure how one is safe to dive a location unless they have done it many times in the past and know the site well.
IMO based on what you have stated, I would NOT say these are examples of *safe* divers. I've dove with a lot of people, including a lot of SB folks, and they all use computers even if they use them in gauge mode. Uncle Pug is an exception (but I have not dove with him). He however does use guages other than an SPG.
