How Much Reliance on Dive Shop Planning?

[Lorenzoid]

There is an oddball device available from a few manufacturers that is basically a combined timer and depth gauge. Once upon a time people diving tables might have gone for these, but nowadays I'm not sure why anyone would buy one instead of a dive computer (or if for backup purposes, a SECOND dive computer). Essentially, the mechanical and electronic parts are the same as those of a dive computer. It seems to me that the difference between one of these devices and a dive computer is little more than software. If one accepts that they need to know their depth and time on every dive, they might as well buy a dive computer rather than something else.

 

[boulderjohn]

Yes, I'm aware that computers can do many things and have many benefits. But aside from extending your bottom time, which can also be read as "reducing your safety factors", I think the primary reason for computers is from the shops and boat operators who say "DIVE COMPUTER REQUIRED" when they are booking classes or dives. Honest, there's no other reason than making profitable repeat sales and service. Safety is NOT their prime consideration.

The first time I ever ran into a shop that required computers was in Cozumel, and I would argue that this was not the case. My first trip after certification a couple decades ago was in Cozumel, and I foolishly tried to use my newly-learned tables on the dive. When a DM (which is required by law there) leads a multi-level dive in Cozumel, you will completely violate the tables and be left in the dark as to your diving. If you don't have a computer, you have two choices: put blind trust in the DM not tl lead you astray or not dive. You do have a third choice, actually--you can hire a private DM to lead the dive for you, and that DM will be questioning your sanity throughout the dive.

I am sure that dive operation and all others like it require computers so that they can have their DMs lead the dives that all their paying customers want to dive and not be limited by someone who has to stick to table limits.

 

[ronscuba]

Gee, Mike, let me say first that I appreciate your clarifying up front that you don't want to be snarky, and that I didn't read your message as snarky at all. See, if I wanted to be snarky (and I don't!) I'd point out that you need only have said "I do not think" and let it at that.(VBG)

Yes, I'm aware that computers can do many things and have many benefits. But aside from extending your bottom time, which can also be read as "reducing your safety factors", I think the primary reason for computers is from the shops and boat operators who say "DIVE COMPUTER REQUIRED" when they are booking classes or dives. Honest, there's no other reason than making profitable repeat sales and service. Safety is NOT their prime consideration.

Yes, a computer is a nice way to figure out saturation and safety for a "Gee, I was at fifty feet for...and then seventy feet for...and hey, how'd I get to 90 feet? How long have I been here?" but the tables still *suffice* for a safe dive, even if it isn't a "maximum" profile. I don't want maximum profiles, I'll accept a little less dive time and err on the side of safety.

And in exchange for that, I save the money up front. The annual o-ring changes. And have no worry about mixing electronics and seawater and aw shucks, I'd have to abort the dive if the damn thing flooded?

The computer can help coach my ascent rate. That's got real value to me. But all this fuss with numbers and what George Carlin (RIP) called "MORE STUFF" ? Nah. I go diving to get away from all that.

OK, so a dive computer is not for you.

What kind of diving do you do and where ? Do you have a regular dive buddy that also does not use a dive computer ? Do you dive from a boat with a dive master leading a group ? If so, do you ask the DM the max depth before the dive and plan/end your dive according to tables and surface with your buddy ? Nothing wrong with this, but I don't think it happens too often.

What do you think about PADI doing OW classes with dive computers instead of tables ? If you had a new diver friend or relative would you tell them to insist on doing the class with tables ?

 

[BoltSnap]

If you're only diving infrequently, it might be more effective to rent one. Or at least, start that way, to get an idea how you like different computers.

You rent one for few days and you bought one but don't own it and have to return it at the end of your dive vacation.

 

[RandomGuy1]

Richie-
Good point but aren't the rechargeable ones limited to the more expensive computers, designed for heavier use? And don't they still recommend changing seals (for those that have them) on a regular basis, to maintain water resistance?

Honestly I couldn't tell which computers have these features as far as cheap computers go. My experience has been as follows: I dove a vyper air for almost 2 years and had the battery changed by my lDS, total cost $16. I now dive a shearwater which no one would consider a cheap computer, but it is easily changed with a quarter and a AA battery, and takes a standard oring that everyone should have in their kit. my backup computer is a nitek q which charges via usb. So reality is I have had one of each style of charging / battery, and my personal preference is for the shearwater's ease of changing battery, but I'm not going to recommend that expensive of a computer to someone in the OP's situation. My least favorite style of battery / charging has to be the nitek because I hate having to charge it every 10 dives or so.

 

[dmaziuk]

The annual o-ring changes.

Ever tried diving yoke regs?

 

[CT-Rich]

I haven't read the entire thread, but here is my $.02. Planning a dive is different than diving the plan. A computer will give you real time data about where you are compared with the NDL. You can safely plan a dive going right upto the line, 80' for 35 minutes followed by a 1 hour surface interval will allow 24 minutes at 50'. You know what limits are, in theory, but a dive computer will tell you much more accurately what you really have done and, importantly, where the line is... I had a dive table in my BCD pocket for years and it never once told me how close I was to hitting deco. Bad conditions cut dives short and setting an anchor can lengthen a a surface interval. A computer will record everything in real time and show you how close to deco you are based on what you actually did.

I was trained in the pre-PDC era and the computer just takes all the human error out of tracking your dive. It starts when you splash, times the dive, tracks depth, surface interval repetitive dive groups, everything. You just need to know how to use it and read it correctly. It isn't a substitute for planning, but idiot proofs your dives. I can't tell you how many time I forgot to set the bevel on my watch or forgot to note when we got back in the boat.

A dive computer is one the few pieces you should buy early, understand thoroughly, use often. This was the sliced bread of diving technology....

 

[doctormike]

A dive computer is one the few pieces you should buy early, understand thoroughly, use often. This was the sliced bread of diving technology....

Yeah, gotta say I don't know WHY there is pushback against such a great innovation. Sure you CAN dive just fine without a computer. But given the advantages and the minimal costs in the context of scuba diving as an expensive hobby to begin with, I have no idea why you would want to.

 

[CT-Rich]

Second, I've heard DAN speakers and read publications, and maybe I've missed it. The use of dive computers does not seem to have lowered the incidence of decompression sickness. The tables (any of them, because there are different sets now) still seem to work just as well. With no moving parts to break. And no repeated maintenance costs.

The only part of the tables that can fail is the soft meaty part. If you think a diver out of the water on a pitching boat with blue lips is going to have a zero failure rate reading a tiny plastic card with perfect lucidity and fidelity, you haven't tried it.

Yes, I'm aware that computers can do many things and have many benefits. But aside from extending your bottom time, which can also be read as "reducing your safety factors", I think the primary reason for computers is from the shops and boat operators who say "DIVE COMPUTER REQUIRED" when they are booking classes or dives. Honest, there's no other reason than making profitable repeat sales and service. Safety is NOT their prime consideration.

I am calling BS on this, saying "reducing safety factors" in quotes as if a PDC is just inviting you into trouble is ridiculous. It's like saying condoms just encourage you more sex by "preventing" STDs. Of course it does. The computer shows you where the approximate line for the NDL is. It won't stop you from crossing it, but at least you can see it better.

The reason boats require Computers is multi-fold. First it makes the diver responsible for her own safety, because, lets face it, the lawyer for Dead Jenny's family is going ask why did you let her die? You had the computer, it's your responsibility. Second, I don't know where she's been. If the DM takes her on a trust me dive, not knowing that she was doing a deep wall dive at 11 PM and is now getting on board for a three tank day, Dead Jenny's family will again look at the dive operator.

Profitability is alway important, and part of that is LIABILITY.

 

[2airishuman]

Yeah, that's a design flaw. Better to get a rechargeable computer or one that lets you replace the AA battery any where in the world with a quarter in about two minutes. Although those computers are probably more expensive, so you probably don't save much by doing that.

The computers that use AA batteries are physically larger.

I change the battery myself every year on my relatively small Oceanic Geo 2.0. It costs $20 for the battery and o-ring. It is not a significant part of my annual diving budget.