dive computer - view of a newbie

[herman]

The tables are always a good backup. As you can see from my other post, computers do die and and can ruin a otherwise good dive. I personally use Oceanic computers. They give me all of the information I need in an easy to read display at a reasonable cost. They don't have some of the fancy stuff but I don't care for that kind of stuff anyway. I am doing a Nitrox class now, guess what, more tables.

 

[jobowker]

I have the Oceanic Data 100. It's fairly simple, only has one button, and shows me everything I want to know. The tissue loading graph gives me an idea of homw much nitrogen I'm theoretically absorbing. It goes from green to yellow to red (no deco limit). It displays my current depth, max depth, and time remaining. The ascent meter at the bottom shows if I'm ascending too fast. The graphs are easy to read. The batteries are user replaceable. There are plenty of more complicated and expensive computers out there, but this one works for me.

 

[scubakat]

I have the Data 100 too, I like it, but the only thing it doesn't record (that I like to know) is the water temperture.

As far as computers vs. tables... I like to log my dives as I go & compare the resulting bottom times between computer & table. (scubanerdy?).

Let's see what the YMCA table says about the profile in question...

50' for 30 min makes you a 'E'.
1:30 surface interval takes you back to a 'D'
leaving 29 minutes for another dive to 50'.

So... say you went on that 29 minute dive to 50'. When you are done you've hit the max time for a 50' dive and are now a J diver. Now you've got to take a long surface interval if you want to keep diving deeper than 40'.

If you did make that 2nd dive for 30 minutes then you have exceeded the ymca table's no-deco limit. And you are done for the day...

Interesting what a difference a minute can make...

-kate

 

[jobowker]

My spg contains a thermometer, so not havig temp in my computer wsn't a big deal. ONe nice thing about the computer is that it can recalculate for multilevel dives. A perfect example of this was one of my dives a couple of weeks ago. I descended the anchor line, and teh anchor was at 62 feet. I started swimming towards the isalnd, and spent the majority of my time (maybe 45 minutes) between 25-30 feet. I was still well within no deco limits when I surfaced, but on the dive tables, you base it on 70 feet (max depth rounded up) for 45 minutes. In cases like this, thee is a big difference between what the tables say and what my computer says. Even though they are based on similiar algorithms, when you are looking at the dive tables, you are basing it on the entire dive at your max depth. This doesn't mean that computer are more accurate, it just means that they can constantly recalculate based on how many minutes at each depth, rather than basing the whole dive on max depth. The time that you noticed the most difference is in examles like the one I just mentioned, where you average depth is a lot less than your max depth.