Dive computer necessary?

[Paulmal]

Computers are not necessary, but helps alot for personal comfort factor. I have done trust me dives in the tropics and other locations where I knew the dives would not be anywhere near the NDL or if we got close we spent so much time at 20' that we could clear twice the deco obligation.

I would recommend the Scubapro Aladin 2g. It is a 2 gas nitric computer so you can grow into it and if you desire to do tec dives in the future it has a gauge mode with average depth that is resettable and a one touch resettable stopwatch for tracking deco stops.
Or if money is no option the just get a shearwater predator, it will do more that most tec divers can as it is set up for Oc, SCR, and CCR. All through trimix.

Safe Diving
Paulmal

 

[peterbj7]

most dive operations plan their dives using the Recreational Dive Planner by PADI and that is perfectly safe and practical

I thought this statement misleading. I know no dive shop which ever refers to the RDP. Most local dives are conducted from the experience of the dive leader, who sometimes doesn't use a computer at all. Most dives are not specifically planned, though in effect they are because most dive leaders know what works.

On practicality, the RDP is sometimes perfectly practicable, but there are many local dives for which one couldn't reasonably be used. The physical profile followed would when translated to the RDP result in a very short dive, unnecessarily short as the use of acomputer demonstrates.

I have been quite surprised on occasion when diving with my Stinger, which is a moderately conservative computer but not especially so when used on gentle dives, how often I would have gone substantially into deco had I not moved well above the group, and that is when the dive leader is himself using a computer. The apparent liberalism of some computers when worn by others is strange.

 

[Bubba1]

You obviously don't dive with us

 

[peterbj7]

Very true!

 

[CarlosCabanas]

The apparent liberalism of some computers when worn by others is strange.

There is definitely a huge difference with brands of computers and how liberal they are. The aeris computers we use at Tranquility Bay give about 10 minutes more dive time on the average profile we are doing on a second dive compared to the Suunto. We have had a couple of guests put their computers into deco while our Dive masters computer was still several minutes away from deco. Evidently just because you are wearing the latest computer does not actually mean you know how to read it!

Cheers,
Carlos

Note: This is not to say don't buy a Suunto, actually the extra conservatism is probably a good thing and I just got a Suunto myself!

 

[cbm32]

... with just one or two exceptions!

You won't be able to dive on tables here as all dives are done as group dives and you won't be in control of your profile. I strongly recommend you get your own computer, learn it thoroughly, and use it on every dive. If you find you're going too close to deco you can always follow the group from shallower.

I would agree with this completely. When I first started diving I would have though, "If I just stay with the group I dont need to spend the money for a computer. That would be a waste". But, I got a chance to buy a decent used wrist mount computer off from ebay at a great price, and so I did. What I found was something I should have known. Even if you "stay with the group" you are still not quite diving the same dive. As little as a few minutes just deeper than the group or shallower than the group changes things. Several dives I thought I was staying with the group only to check and see that I was nearing my NDL because I had spent some time deeper looking at something. So I had to go up several feet and mirror the group for the rest of the dive. Another time I thought we were all pretty much doing the same dive but low and behold three members of the group (including the DM) ended up getting locked out by their computers and had to sit out the next days dives.

So, save yourself some aggravation/anxiety and get a computer.

 

[diverrex]

My first 14 dives were at Belize with no computer. The DM said "just always stay a little above me". It was after doing those dives and trying to make sense of the multi level profile against tables that I quickly realized I was doing trust me dives and had to get a computer to avoid doing that.

 

[Tigerman]

At wich point youre STILL doing trust me dives, only that you now trust your own computer rather than the DMs..

Doing it should be fine, but computers does vary with regards to algorithms and conservatism, so knowing whats going on and having an idea if the profile the computer let you do is sane is not a bad thing.
My computer for example has variable ascent rates - somthing many computers dont and as such I might end up with a much faster, or slower ascent profile than whoever I dive with, or I can ignore what the computer tell me and go by other things..

 

[diverrex]

At wich point youre STILL doing trust me dives, only that you now trust your own computer rather than the DMs..

Doing it should be fine, but computers does vary with regards to algorithms and conservatism, so knowing whats going on and having an idea if the profile the computer let you do is sane is not a bad thing.
My computer for example has variable ascent rates - somthing many computers dont and as such I might end up with a much faster, or slower ascent profile than whoever I dive with, or I can ignore what the computer tell me and go by other things..

True, no different than "trusting" tables is a trust me dive, however knowing that tables probably have more conservatism built in than computers. I would much rather trust a dive computer than a DM.

 

[jlevine]

I just got back from Belize and had a wonderful time. I used my computer throughout this trip as I do for pretty much every trip. The divemaster also had a computer. He asked everyone without a computer to stay above and behind him. It was quite interesting to see some computerless folks dive deeper than the DM on both the first and second dives without appearing to think about it while both the DM and I were watching our NDL. My computer is certainly conservative (Suunto Cobra 1st Gen) but I really am surprised that someone didn't get bent. To the original poster, as others have said you can buy a computer for a couple hundred US$. If you can afford it, it's very well worth it. If not, I suggest renting one.