Do I really need a computer?

[TMHeimer]

The Wheel hasn't been part of OW course for years. I may have seen one once. Wonder how difficult it is to use. Another interesting gadget is the Nav Finder.....too much work.

 

[The Chairman]

Do people even go diving these days without one?

Rarely... moreover, I won't dive with you if you don't have one. There are a lot of people like me!

 

[boulderjohn]

The first place I dived after certification was in Cozumel, and I learned that if you want to have a clue what you are doing, you can't do it with tables. You are required by law to follow a DM, and with a DM leading the dives, ALL the dives will be multi-level dives, and you will be off the charts after the first one. After my first dive in Cozumel, I whipped out my tables to log the dives and realized that, according to the tables, I should have been on my way to the chamber. The other divers on the boat were amused. they told me my tables would make a decent Frisbee.

So, if you want to follow the DM like a mindless sheep and just trust the DM to keep you safe, no, you don't need a computer. I sure don't want to dive like that, though.

 

[Hoag]

I remember one day in particular that demonstrated the usefulness of a computer. Admittedly, this is an extreme example, but it is a real life dive day.

Dive 1: Great Blue Hole in Belize
Depth: 130 feet
Bottom Time: 45 minutes

Surface Interval: about 45 minutes

Dive 2: Reef @ Great Blue Hole
Depth: 60 feet
Bottom Time: 55 minutes

Surface Interval 1+30 (over lunch)

Dive 3:
Depth: 50 feet
Bottom Time: 55 minutes

Surface Interval: about 1 hour

Dive 4:
Depth: 50 feet
Bottom Time: 45 minutes

If you went by the tables, a dive day like this would be reckless at best, and possibly fatal. However, on the dive in the Great Blue Hole, we were at the max depth for only a few minutes before we started to ascend. The second dive, was similar in that I was only at max depth for a couple minutes before I came back up into the shallow reef system surrounding the Great Blue Hole and actually spent most of the dive at about 30 feet. I had similar profiles on the remaining two (afternoon) dives. The dive computer based my NDL on my actual profile. The tables, however would only take into account the max depth, the bottom times, and the surface intervals.

By keeping an eye on our computers, we were not only able to do a dive day like the one above, but we were able to do it and stay well below our NDL all day.

 

[dirkadirk]

Rarely... moreover, I won't dive with you if you don't have one. There are a lot of people like me!

I'm of a similar mind - however if I do get buddied up, I damn well expect to see you doing your gas calcs and dive planning, and then briefing me accordingly as to your turn around pressures and timings, deco depths and timings. I have called a dive before it started because my insta-buddy didn't think any of that was necessary and was just gonna go to half a cylinder and then come back. I wasn't popular, but the dive op did reschedule a dive for me later in the week to make up for me missing that one, which was pretty decent of them to be honest.

 

[TMHeimer]

Since we all knew it would come back to computers vs. tables (when hasn't it?), I'll say it depends. Since the OP mentioned Cozumel, I figured multi level and probably drift dives, thus recommended computer for such. If your typical charter day is like mine---2 tank dive, first to 90', second to 60'--I'll be on the bottom the whole allotted time(s) collecting shells---you can do fine with tables. Doing such square profiles will not send you off the charts, and tables will probably match up reasonably with what the computer says. But, I take the computer too of course. Depends on the type of diving.

 

[cneal]

The Wheel hasn't been part of OW course for years. I may have seen one once. Wonder how difficult it is to use. Another interesting gadget is the Nav Finder.....too much work.

I keep a wheel in my log book. The only use it has had in many years is to be pulled out to get a horrified expression from instructors. If you didn't take the PADI Multi-level Diving specialty you won't know how to use it.

 

[Kevo88]

I keep a wheel in my log book. The only use it has had in many years is to be pulled out to get a horrified expression from instructors. If you didn't take the PADI Multi-level Diving specialty you won't know how to use it.

PADI's newer eRDPml that you download when doing the e learning is a pretty easy way to plan multilevel dives. I'm still in the computer camp, but it is a useful planning device for basic dives.

 

[CT-Rich]

If you are going to spend several thousand dollars on dive trip, why would you limit your diving by relying on using tables that only approximate your dives? If you follow the DM, you lose the ability to use your own judgement about the deco limits. Neither of those seem like good options when you could buy or rent a computer for next to nothing.

My guess is you will get to the resort and either feel like an idiot after the first day because you losing so much bottom time or you will simply start making trust me dives and hoping no one notices you doing no planning at all. Neither makes you look good or makes the trip more enjoyable.

Would you take a case of beer on a boat and hope there was a bottle opener and ice?

 

[TMHeimer]

PADI's newer eRDPml that you download when doing the e learning is a pretty easy way to plan multilevel dives. I'm still in the computer camp, but it is a useful planning device for basic dives.

I feel it may be useful to get a general idea of your plan. I mentioned in another thread somewhere that you have to have a pretty good idea of how much time you'll spend at each depth, which means probably knowing the site from past experience. If you decide to stay at one level a bit longer or shorter your plan will not be accurate. So, you'd just follow your computer. It wouldn't be a practical way to plan a wall dive or anywhere you just gradually ascend from your initial deep depth. But it is an interesting toy to play with and to get a knowledge of multi-level diving.