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View Full Version : Is it heresey to dive without a computer?



Steve Scuba
10-18-2007, 16:40
Ok, so my friend and I are getting into diving, but we aren't rich doctors and lawyers (got that from another post), and we're trying to get good gear that won't kill our bank accounts.

So we put our heads together and figured that we could put together a decent regulator package with analogue gauges, and save quite a bit of dough.

The idea would be to buy such a regulator setup now, then maybe a BCD in a few months (perhaps with Christmas gift cards), and sort of add gear as we go, renting what we didn't have in the mean time. If we feel cash heavy in the future, a nice non-AI wristmount computer could be in the cards.

But even the training manuals for the dive course sort of blow off the idea of diving without a computer as a ridiculous idea. Seems to me that a good SPG and depth gauge along with monitoing and planning is the way it's been done for decades, and should still work well. And, as an added bonus, we sharpen those planning and monitoring skills as beginning divers, and don't immediately start depending on the computer to tell us what to do.

What do you think? Heresey, stupidity, overly cheap, or not?

cshel
10-18-2007, 16:50
Yes, you can dive without a computer. The big difference is going to be in your bottom times. When you dive by the charts, your whole dive is counted as your max depth. It is very rigid and one dimensional. With a computer, it constantly recalculates your status. I don't know any divers who immediately go to X feet and stays exactly at that depth and then back to the surface. You usually got up and down, investigating different things.

Now, if you and your buddy only dive together, you might not notice anything. If you dive with someone who does have a computer, they will have to come up because of you... and they will not wish to dive with you often in the future.

datamunk
10-18-2007, 16:53
Computers are a tool, not a replacement for tables. You still need to know how to work your tables and plan and what not.

What you are doing makes sense. Dive gear IS expensive, and a lot of people either cant afford to buy the best up front, or can and arent really enthrawled with that idea.

I am still slowly acquiring my gear to this day, 7 years after certification. I'm a young college student slowly makin it happen. A good idea is get a good job at a dive shop, theres lots of benefits of it, as a part time thing. For example, i know aqualung does a 6 and 6 deal where, you sell 6 regulators or ocmputers and 6 bc's , you get somethin for free (worth the average oft he items at cost). so, i ended up with a cobra and atx100 for total spent of aobut $125. i moved from the area and figured i wouldnt be diving much so instead of lettin my gear sit around dry i sold it to friends (made a good bit of cash) but now i regret it ;P

plus u get a discount (maybe im not supposed to tell people about the incentives program, whatev)

anyway, do it at your own pace. computers do make diving much more enjoyable for me, especially if its air integrated. but now im down to a lil computer for bottom time depth and temp and thats it, so back to old school :(

RoadRacer1978
10-18-2007, 17:03
If so, I'm a heritic...

As Cshel stated a computer will give you much more botom time what what is called a multilevel dive. (not staying at max depth the entire time). The computer will recalculate you depth and NDL throughout the dive and give you credit for not being at you max depth as you hover around at shallower depths.

With tables you are going to calculate you dive at max depth plus total bottom time. So if you were say divin off of a boat. You decend down to you max depth and stay there until your ascent then a computer would be of no real advantage to bottom time.

So there are definate advantages to having a computer. That does not mean you have to have a computer to dive. IF you and your buddy are both using tables then that is great. You can dive and that is what is important. If you are using tables and your buddy is using a computer, he may get a little frusterated with you on repetive dives. Since you are goverened by the most consertvative limits you would have alot less bottom time on multiple multi level dives and his dives would be cut much shorter.

I am planning on getting a computer when I can afford it. For now I am happy to just be diving. Don't feel like you have to purchase a computer just to dive.

Kingpatzer
10-18-2007, 17:52
My first piece of gear was a used cheap comp - -- very glad I went that route. But no, they're not essential, just really useful.

CaptainRon
10-18-2007, 18:20
ST has a good package for $399. Add your 10% on top of that and that would be the way to go. You might not have all the bells and whistles, but you will be diving!:smiley20: You can always upgrade later as finances allow. Anytime you upgrade, you will then have a piece of backup gear.

NitroWill
10-18-2007, 18:34
Honestly, I would recommend getting a BC first. The reason being, not all dive shops will have a good quality bc that will fit you correctly and comfortably. Also, each bc is different and its good to know your gear.

On the other hand, in general most rental regs will be about the same - as long as you rent from a trustworthy shop there wont be much any difference and obviously there isnt really a "wrong fit"

In terms of computer - they arent really necessary. I dove 4 years and hundreds of dives without a computer. Yes, they are a good tool to have - but no - definitely not necessary.

BobbyWombat
10-18-2007, 19:35
If you dive square profiles, and your buddy dives tables too.....getting a computer later may be the right answer for you. Certainly nothing 'wrong' with going that way.

For multilevel diving (shore diving many times), a computer really maximizes your time underwater.

Compudude in another post had a some good comments on a similar subject, which I will attempt to paraphrase:

Basically diving is very time consuming above water, all for precious few minutes below water. Computers maximize those precious few minutes.

That said, consider the type of diving you intend to do. Maybe getting the DC first is the right move for you (it was for me). Maybe getting a reg or a BC first is the right choice for you.

picxie
10-18-2007, 20:18
A computer was my very last purchase. I learnt to dive years ago but only really got into it again about 12 months ago. Decided to get my own gear but have been diving for a year without a computer. Have only just recently purchased one (wrist) and did my first diving with it last week. It is handy, but not essential. I still log my dives and use the tables. So yes, if you are trying to save some money then a computer can be left till last :)

Splitlip
10-18-2007, 20:32
If money is an issue, a computer is the last thing you "have to " purchase for the reasons others have said. God has already given you a pretty good one.

And when you do purchase a computer, you should continue to plan your dives.

Aussie
10-18-2007, 20:34
It is not Heresey until you expect the "Spainish Inquisition".

http://www.youtube.com/watch?v=P1iBbBL1040&mode=related&search=

Aussie:smiley2:

Splitlip
10-18-2007, 20:52
Great stuff.
Thanks for sharing.
(I'm a fan.)

bperrybap
10-18-2007, 20:54
Just some things to consider.

The price difference between a full analog setup
and a SPG+Air-only computer isn't as much as you might think.
Remember, when you have the computer you don't need
the depth gauge.

There are a few really nice Air-Only computers out there
for about $150. (Aeris XR-1, Oceanic Veo 100)

A 2 gauge SPG + depth gauge is around $110 to $150.

There are a couple of nice Air-only consoles with a SPG
and computer for $199.

For $15-$20 more you should be able to get a wrist boot
and move the computer from the console to your wrist with
the Oceanic Veo 100 model.

Thats only a $50-90 difference to swap the analog depth gauge
for a computer.

These models are basically the same as the higher end
Aeris/Oceanic models but limited to Air (no nitrox),
no PC downloading, 12 instead of 24 dive logbook and no audio alarms.

ScubaToys also has some great packages that combine
reg/octo/console & computer for some savings as well.

--- bill

Steve Scuba
10-19-2007, 00:06
It is not Heresey until you expect the "Spainish Inquisition".

http://www.youtube.com/watch?v=P1iBbBL1040&mode=related&search=

Aussie:smiley2:

Nobody expects the Spanish Inquisition! My favorite Flying Circus Episode!

BuzzGA
10-19-2007, 01:23
I got certified as a teen in the mid-80's and got my first computer last year. A good fitting BCD and a reg set up that is good for you would be my first priorities

danielh03
10-19-2007, 01:52
As already stated, you can really increase your BT/NDL with one. So if you are on a live abord, or chartered trip, you can make the most of your diving with one. If you want to dive tables, you might consider renting a computer when you feel its needed.

cummings66
10-19-2007, 07:36
If you want more bottom time and don't want to buy a computer, look for a wheel. It can give you times nearly equal to a computer if you plan the dives right.

A computer is more useful for diving areas you don't know, but if you know an area or keep track of depths you can reverse figurea dive with a wheel and gain times. It's really useful though for planning multilevel dives, very similar to a computer but it's not real time.

For what it's worth, some dive ops require computers. That's the only reason I bought my first one.

Zenagirl
10-19-2007, 07:42
Personally, I can't imagine diving without my computer. The minute I got one it felt like the diving world opened up and my dive times nearly doubled. With as cheap as you can get one now, for me it's a "must have" item.

YMMV

Steve Scuba
10-19-2007, 09:24
All very good advice. I think after reading all of this, and hearing other testimonials from some divers that I work with, I think that the wisest course of action at this point would be to seek a package with an inexpensive computer set-up. Thanks to bperrybap and others for bringing that to my attention... it really wasn't as much savings as I thought.

Stopped by the LDS yesterday to pick up my rental gear for my final OW certification dives this weekend, and found that the savings between analogue gagues and the reg set with a VEO100 was only $100 bucks. Seems like that might be the way to go, then in a year or so after some savings I can convert to that new Wisdom 2 that I saw that made me drool a little.

Lone Frogman
10-19-2007, 11:35
I dove over twenty five years without a computer. Never seen the need. Now I have two, because I'm so lazy I don't dive with out one any more. No tables, no timer, no depth gauge and I can down load all my dives.

MSilvia
10-19-2007, 11:53
I just flooded my basic Genesis Resource computer recently, and don't think replacing it is a high priority for me. Generally speaking, most of my dives don't benefit much from having it.

Most of my dives are local, and they're either shore dives or chartered wreck dives. If shore dives, I'm likely doing two dives to 40 fsw or less, and bottom time is hardly an issue. I'd run out of gas long before hitting NDL on the second dive, so knowing my depth and time are really almost unimportant on those dives... turn pressure is what sets the limits there.

If I'm doing a wreck dive, I can pretty much count on staying close to the planned depth if it's a scouting/sightseeing dive, and I can be more specific about m y planning if it's a wreck I'm familiar with. I can use tables (or cut my own using vPlanner), and not really miss out compared to other divers using a computer. In fact, I occasionally will plan a boat dive with a mix and deco schedule that lets me get a lot more bottom time than folks doing an NDL dive on a computer.

The only times I find a computer to be really useful is when I'm diving a site with a lot of terrain variation at moderate depth, or planning a multi-level NDL dive. My bottom timer does the job just fine for most applications.

webwidejosh
10-19-2007, 12:53
If so, I'm a heritic...

As Cshel stated a computer will give you much more botom time what what is called a multilevel dive. (not staying at max depth the entire time). The computer will recalculate you depth and NDL throughout the dive and give you credit for not being at you max depth as you hover around at shallower depths.

With tables you are going to calculate you dive at max depth plus total bottom time. So if you were say divin off of a boat. You decend down to you max depth and stay there until your ascent then a computer would be of no real advantage to bottom time.

So there are definate advantages to having a computer. That does not mean you have to have a computer to dive. IF you and your buddy are both using tables then that is great. You can dive and that is what is important. If you are using tables and your buddy is using a computer, he may get a little frusterated with you on repetive dives. Since you are goverened by the most consertvative limits you would have alot less bottom time on multiple multi level dives and his dives would be cut much shorter.

I am planning on getting a computer when I can afford it. For now I am happy to just be diving. Don't feel like you have to purchase a computer just to dive.

Have you tried ebay? I got a Suunto Vyper a tad over $200.

CompuDude
10-19-2007, 13:32
The issue has been covered to death, but my personal recommendation for people looking to buy their first gear is to buy a BC first.

The reason is simple: Buoyancy is the single most crucial skill for new divers to master. That is complicated by rental BCs in various states of repair and in various styles and configurations. Get your own BC and you can start dialing in your buoyancy and trim, and get a good feel just where everything is on your body... a huge advantage.

Second is exposure protection, for the same reason as the BC: Consistent buoyancy compared to well-used rental gear. Wetsuits also are often a relatively smaller purchase compared to the next big thing, regs. Note: local environmental considerations can change this one a bit, of course... if local water dictate a cheap shorty vs. a thick high end 7mm vs. a drysuit, this may have to wait a while, or may be barely worthy of thinking about.

Some prefer to buy regs first, but I personally feel as long as you have a shop you can trust, regulators all pretty much work the same way: Insert in mouth and breath. So I say buy regs third, or after the buoyancy-related purchases are done with.

The LAST thing you should buy (unless you buy it at the same time as the regs, in a package for instance) is the computer.

Ok, the real last thing is tanks, but you get the idea.

There's my recommendations, built over 20 years of buying and selling gear, and helping others do the same.

RoadRacer1978
10-19-2007, 13:43
If so, I'm a heritic...

As Cshel stated a computer will give you much more botom time what what is called a multilevel dive. (not staying at max depth the entire time). The computer will recalculate you depth and NDL throughout the dive and give you credit for not being at you max depth as you hover around at shallower depths.

With tables you are going to calculate you dive at max depth plus total bottom time. So if you were say divin off of a boat. You decend down to you max depth and stay there until your ascent then a computer would be of no real advantage to bottom time.

So there are definate advantages to having a computer. That does not mean you have to have a computer to dive. IF you and your buddy are both using tables then that is great. You can dive and that is what is important. If you are using tables and your buddy is using a computer, he may get a little frusterated with you on repetive dives. Since you are goverened by the most consertvative limits you would have alot less bottom time on multiple multi level dives and his dives would be cut much shorter.

I am planning on getting a computer when I can afford it. For now I am happy to just be diving. Don't feel like you have to purchase a computer just to dive.

Have you tried ebay? I got a Suunto Vyper a tad over $200.

$200 is not even close to the computer I want. Probably going AI most likely Oceanic VT pro or VT3. Saving for the computer I want, no need setteling for something less.

mitsuguy
10-19-2007, 14:45
I bought wetsuit and computer first... Not a big fan of using a rental wetsuit, but I will if I have to... Computer - well, ST had a awesome deal on a wrist mount Atmos 2 that I couldnt pass up... Now, I have my own BCD, so the only thing I lack when diving is a reg setup... that will be coming within the next couple weeks...

I agree with the buy the BC prior to regulator as well... You will gain a lot by being more comfortable in your own gear - and as was said already - for the most part, a regulator is a regulator, they all work pretty much the same, and the comfort you gain by having your own bc is more than the comfort you would gain by having your own regulator... (plus, depending on BC, its cheaper than a regulator setup anyways)

reeldive
10-19-2007, 15:20
I dive a computer and a bottom timer and depth gage as a backup. It has saved a dive for me when my Sherwood profile died a depth about mid dive ie 20 min into a 70 ' dive on a the liberty ship off PC. was able to enjoy another 20 min of diveing because I had my depth gage and bottom timer.
1st dive of the day 70' = 40min BT My air is usually down to time to leave by then any way. Got out my tables during the SI and was able to do a second dive for 25 min on the same wreck after lunch Wouldn't leave home witout my tables! my computer used to give me about 35 min on simalar profile an SI in the past.

Splitlip
10-19-2007, 17:14
All very good advice. I think after reading all of this, and hearing other testimonials from some divers that I work with, I think that the wisest course of action at this point would be to seek a package with an inexpensive computer set-up. Thanks to bperrybap and others for bringing that to my attention... it really wasn't as much savings as I thought.

Stopped by the LDS yesterday to pick up my rental gear for my final OW certification dives this weekend, and found that the savings between analogue gagues and the reg set with a VEO100 was only $100 bucks. Seems like that might be the way to go, then in a year or so after some savings I can convert to that new Wisdom 2 that I saw that made me drool a little.

Since you have decided to go that way, then I would suggest a Nitrox computer.
You'll likely be diving notrox sooner then later and if you are stuck holding an air computer you will be kicking yourself. Air computers are pretty hard to sell used.
And with tables, calculating your NDL's for air is easier than doing it for Nitrox. A nitrox computer will serve you better tomorrow than an air computer will serve you today.

hoop
10-19-2007, 21:40
I'm going to have to chime in here... Lots of good advice. BUT, here's my take on things.... Get your BC first..... Buoyancy is key.. Then Reg..... Then thermal protection. Keep diving your charts, but just realize that the charts are a GUIDELINE only..... And an antiquated guideline at that.... I dive lakes a lot. Guess what? When I dive a lake to say, 60ft, I'm not going to STAY at 60ft, because of rocks, obstacles, etc.... I may wanna see something a little lower, or up higher... Guess what? You just blew your dive profile.... It's useless. (if you follow that profile) This is where a computer comes in handy... It is constantly re-evaluating the profile. This is where the computer is essential to me.... I might catch some flak for this, but let's face it: Who follows their profile to a T? I sure as hell don't. If there is a fish I wanna look at 10ft lower than my profile, I'm gonna go look at him.... I"m not trying to tell you to be a rogue diver, but there realistically has to be some flexibility in your profile..... I would have a general idea as to how long I can stay at what depth, but that doesn't dictate my dive... Just my .02 YMMV

Krakenn
10-19-2007, 22:04
Computers are great and provide an added level of safety and recreational enjoyment to a dive.

But as all the others have sstated the best option if you have a cash flow problem is to get yourself some good Analogues and use your tables.

The only problem i ever encountered was one dive operator would not let my wife dive on a Wreck on the basis that she did not have a computer.

i later brought a Airlab for her but it still irritated me about the operator, which i never used again on that wreck btw.

All the best see you down there. -

Kraks

chace_nicole
10-20-2007, 00:20
I bought wetsuit and computer first... Not a big fan of using a rental wetsuit, but I will if I have to... Computer - well, ST had a awesome deal on a wrist mount Atmos 2 that I couldnt pass up... Now, I have my own BCD, so the only thing I lack when diving is a reg setup... that will be coming within the next couple weeks...

I agree with the buy the BC prior to regulator as well... You will gain a lot by being more comfortable in your own gear - and as was said already - for the most part, a regulator is a regulator, they all work pretty much the same, and the comfort you gain by having your own bc is more than the comfort you would gain by having your own regulator... (plus, depending on BC, its cheaper than a regulator setup anyways)

Hey I was looking at the atmos 2, wishing there was a wrist mount..didn't see it online. Guess I will have to give ST a call..please post link anyone if I just missed it.
~Thanks

deepdiver47
10-20-2007, 09:32
I agree, if you are starting out and cash is an issue then you can put it down on your list.

Personally, I have 2, a primary and a backup and would feel naked without having one (I design computers for a living. The best thing about them is that after the dive you download the data to a program and it gives you a great start on your logbook.

kyfriedchipper
10-23-2007, 02:17
always good to check the tables and then have your computer for backup - as somebody told me in this forum: "two is one and one is none"

BobArnold8265
10-23-2007, 12:08
I think it's a bit safer to dive with a computer. You don't have to memorize your bottom time and it does a better job of measuring your nitrogen absorbsion. However, it is not an absolute requirement. Although computers can be expensive, you can find a good used one for pretty cheap. I just bought a used Vyper on eBay as a back-up for about 1/3 of what a new one would cost. Just something to consider.

bversteegh
10-27-2007, 23:41
I think you are making a wise choice. Like lots of others on this post - I dove for almost 20 years before my first computer - I would never go back. Probably not a big deal if you mainly do a single dive with your friend - but I would never do a multi-day trip with repetitive dives on tables.

Also, watch ebay or used gear forums - lots of people are now nitrox certified - so lots of good air only computers on the market for a pretty good discount....

ScubaJenn81
10-28-2007, 08:00
I have yet to dive with a computer, I can not justify the expense right now, but then again, no one I dive with has one either. I think that is a huge factor, as others have already stated.

nathan
10-30-2007, 09:15
I think it really depends on what you and your friend plan on doing.

If you plan on going out on your own with the two of you then using the tables no problem.

If you plan on like going with others and doign one dive. Sure No problem.

If you plan on going out and doing say two dives with a long surface interval in a day, no problem.

If you plan on say going on a dive boat and diving 3-4 dives consecutive days in a row, then you need a computer.

The reason why I say you need one is you will quickly discover even with a computer if you figure out your dives with traditional tables before your last dive of the day the tables will tell you no more diving! But your computer will tell you have plently of bottom time left to do one more dive.

This has to do with multi-level diving. Your computer is taking in account that you were at different depths during your dive for different amounts of time, where your tables aren't and most newly certified divers are going to be using the tables with their maximum depth.

Obviously if you can't afford computers no big deal, you can always rent 'em for a trip.

I think alot of the high-end dive boats want to see an advanced card (for depth), and a computer (for multi-level dive profiles).

I'm just saying your computer will typically allow you to dive more then your tables if you are just doing max depth & bottom time, and if your at a resort planning on doing a ton of diving, or on a boat, your dive tables will obviously not match the computers accuracy for a multi-level profile.

-Nathan

RonFrank
10-30-2007, 09:29
The Aeris Atoms II is a GREAT computer. Mine has been rock solid for years, and I've replaced the battery once.

It came in wrist mount versions, but this computer was discontinued when the XR series was released.

I would not hesitate to purchase a used Atmos II on Ebay from a seller with good feedback. You can likely get them for under $200, but I've not looked.

I purchased mine for about $200 when they were just out from an out of business dive shop. So keep your eyes out for deals, they are out there, but you have to be watching.

RonFrank
10-30-2007, 10:08
It really depends a lot upon your profile as to if a Computer is necessary for Max bottom time, and multi-day diving.

If you were diving Jupiter, FL which has a relatively flat profile at 80feet, than having a computer does not provide much additional BT because it's a flat profile.

If you are diving shallow reefs in the 14~40foot depth, a computer does not do much as the dives are shallow, the NDL times are in the hours, and again the profiles are relatively flat.

If you were diving Coz over a week, that's a horse of a different color. Most diving there starts deep, and the profile is one long slow ascent. It's next to impossible for anyone to predetermine the exact depths and times, and take advantage of the potential BT that a computer is going to award you for that type of diving. Some OPs require a computer for these types of dives.

Calculating the NDL over multi dive days, and repetitive dive days using flat profiles, or even the wheel is going to severely penalize you, and significantly reduce your BT.

So the answer is, sure diving without a computer is possible, and can be safe. But a computer is IMO one of the first equipment purchases that should be made. They do more than just calculate NDL. They monitor your ascent rate, and can warn divers when they break limits that can be set prior to the dive.

For example, when I dive a wreck with the sand at 140 feet, and the deck at around 100' I generally set my depth alarm to 120'. If I go below that preset depth, I get an alarm which is good because I've planned not to exceed that depth. If we have modified our plan slightly due to diving conditions and we are seeing something cool, I can ignore the alarm but it's still nice to have the ability to alarm on things like ascent rate, max depth, time, and gas in the case of an AI computer.