How often do you actually need a computer?

[Skeeter1097]

I dive mostly in the Palm Beach's, Fl area. Most divers that I know get grate bottom time. Most can go Deco on a 80cf. on most dives. We do 2 tank dives most of the time and 70to 100 dives a year. 50% of the dives we would go Deco if we did not have computers.
Think of it this way 755 of the dives that we where only on the yellow. If you where diving tables you my have goon Deco.
What gas are you breathing in order to dive 100 ft for 2.5 hrs and not go deco. The ndl well not me.

 

[sea nmf]

When I do boat dives here, I use it on the deep dives and to watch the SI data. But I don't need it. I use my computer mostly for gauge data; time, depth. The tables would work fine for dive planning as well as a watch. But the computer makes it more convenient.

 

[TSandM]

It's a great question, Gray!

I know that a great many dives I do locally are profiles I could do in my sleep. I could probably tell you what the no-deco time on any of my computers would be at each point in the dive, and I know the normal flow through the dive stays within limits. Other sites (like Edmonds) are places where you will get cold or bored LONG before you hit deco limits, even on air.

When I have gone to unfamiliar places, the dives have often been guided, and the guides shape the profile to keep the divers out of deco. This was the case, for example, in Cozumel, which is a place where you COULD run into deco pretty easily, given the readily accessible depths.

The dives I can think of where, if I were a computer-following person, I would have needed one, are Waterman's Wall (where the top of the wall is between 50 and 80 fsw, depending on where you hit it, and it goes down from there), the Saanich Inlet cloud sponge dives, and Sares Head (a fairly sheer wall down to about the 200 foot range).

But I dive big tanks and have a small woman's gas consumption. Bigger people with smaller tanks wouldn't even run into issues in those places, because gas would limit more than deco.

 

[gcbryan]

I dive mostly in the Palm Beach's, Fl area. Most divers that I know get grate bottom time. Most can go Deco on a 80cf. on most dives. We do 2 tank dives most of the time and 70to 100 dives a year. 50% of the dives we would go Deco if we did not have computers.
Think of it this way 755 of the dives that we where only on the yellow. If you where diving tables you my have goon Deco.
What gas are you breathing in order to dive 100 ft for 2.5 hrs and not go deco. The ndl well not me.

I think he mistyped when he wrote 100 ft...he either meant 10 ft or it makes no sense to me either.

 

[gcbryan]

It's a great question, Gray!

I know that a great many dives I do locally are profiles I could do in my sleep. I could probably tell you what the no-deco time on any of my computers would be at each point in the dive, and I know the normal flow through the dive stays within limits. Other sites (like Edmonds) are places where you will get cold or bored LONG before you hit deco limits, even on air.

When I have gone to unfamiliar places, the dives have often been guided, and the guides shape the profile to keep the divers out of deco. This was the case, for example, in Cozumel, which is a place where you COULD run into deco pretty easily, given the readily accessible depths.

The dives I can think of where, if I were a computer-following person, I would have needed one, are Waterman's Wall (where the top of the wall is between 50 and 80 fsw, depending on where you hit it, and it goes down from there), the Saanich Inlet cloud sponge dives, and Sares Head (a fairly sheer wall down to about the 200 foot range).

But I dive big tanks and have a small woman's gas consumption. Bigger people with smaller tanks wouldn't even run into issues in those places, because gas would limit more than deco.

Yes, around here most of the walls would require depth info at the least but other than a few wrecks that's about it.

 

[Eric Sedletzky]

I lost my computer several years ago when my buddy flipped over my kayak and it went plop into the ocean. After that I didn't have money to replace it so a friend of mine that owns a dive shop traded me a bottom timer for a plate.
Anyway, I don't miss the computer. It was nice while I had it but I never got close to the NDL's on it except for once on a deep dive in Socal on Farnsworth Banks. I over stayed my welcome at 110 feet by one minute according to the Suunto Vyper so I headed up. At 60 feet I wanted to begin doing deep stops but the computer wanted me up at 15 feet. I ignored the computer and stuck with doing stops every 10 feet till I got to 10 feet then I was going to use the remainder of my air and call it good. When I got to 15 feet the computer wanted me there for 15 minutes or something crazy because the algorithm didn't allow for deep stops. I almost got rid of it then but the next kayak adventure took care of that.

More recently doing dives with my bottom timer, I was on a trip to the Channel Islands and we were doing 6 dives a day. I was using the provided 32% Nitrox and was depth averaging and religiously doing a series of stops on each dive. I sat down and did some table math and realized that my figuring was darn near spot on and I didn't get anywhere near deco.

Where I normally dive in Northern California we just do dives typically in the 50 to 80 foot range and sometimes shore dives that never get deeper than 30 to 40 feet. 2 dives up here in all the heavy gear and you're spent. So I don't see a need to replace my computer.

It's also amazing how good you can get when you are forced to pay attention and think about what you are doing with depth and time. I think it's good mental exercise rather than blindly following what the computer tells you to do.

 

[gcbryan]

One thing I've always enjoyed doing is trying to guess my depth and time just before I look at the computer and then confirming whether I was close or not. The same goes for my spg. I know that this is nothing new and that many people do this but I find it helpful.

Depth is hard to guess unless you have other clues so jumping off a boat in open water with no other clues you aren't going to guess depth but at sites with other features you will have clues.

Due to our sometimes limited viability I use a compass on most dives but sometimes I'll navigate just using natural features just to see how well I can do without the compass. In most cases I'd rather have a compass than a depth gauge (luckily I have both!) but when I can't detect depth at all then I'd rather have the depth gauge than the compass.

 

[SurDo2]

You never need a computer.

 

[ucfdiver]

What gas are you breathing in order to dive 100 ft for 2.5 hrs and not go deco. The ndl well not me.

32% bottom mix, 100% deco mix. Wasn't implying this was a NDL dive, we certainly had to pay the price of deco boredom on that one. I was just saying that for those types of dives, or for 30 minute reef dives, I haven't needed a computer, and typically I get just as long, if not longer bottom times than my computer using buddies. I've noticed by using min deco tables DIR-diver.com - Using the min deco table that on repetitive dives, the minimum deco really extends the amount of time I can spend, and often by dive 3 I'll be much cleaner than those using a computer and doing a 2 minute safety stop.

50% of the dives we would go Deco if we did not have computers.
Think of it this way 755 of the dives that we where only on the yellow. If you where diving tables you my have goon Deco.

Only because you're not depth averaging using a bottom timer. All your computer is doing, is taking multiple samples and keeping track of tissue loading at various depths, you can do the same using some of the tables out there, or a ratio deco theory.

Although, I will admit, I don't have the computer specialty, nor do I have AOW....so maybe I should stay out of this area of the board

 

[psychocabbage]

My computer handles my depth and time so for me its needed on every dive. I dont ever wear a watch so the only way I know the time is from the computer.