Dive Computer vs Dive Watch

[freewillie]

I would recommend a watch and depth gauge over a computer. Not just to save money but to reduce your dependency on something that can quit on you if the battery fails. The other problem with computers is while they can give you more bottom time it is at the expense of reducing your safety margins. To avoid carrying tables with me I used permanent ink to write the no decompression limits on the arm of my wet suit

A dive computer would increase the margin of safety since they calculate your bottom time and nitrogen loading on actual depths dived even at multiple levels. The dive to this depth and calculate NDL time is less accurate since it assumes all your time is spent at a single depth. A dive computer would calculate that you spend 'x' time at 65 feet and when you ascend to 45 feet you get the extra time instead of assuming you are still at 65 feet.

As for the battery failing, they can't fail in a watch too? I have a watch that has been sitting in my drawer for over 6 months because I'm too lazy to take it and get the battery changed. Since the battery is dead it doesn't tell time. If you are concerned about the battery dying on your dive computer pay attention to the battery indicator or change the batteries before your big vacation.

Besides, how much space can the tables take up? I generally keep a set in the dive bag just to have on hand. They are good practice to dive plan especially when with my daughter to get a ballpark for how long we expect to dive. The actual dive is timed by how fast we use our air. Since we are 65 ft or shallower we will run out of air before we flirt with NDL's.

---------- Post added May 15th, 2012 at 02:28 PM ----------

I just did some dives with my newly cert. daughter who trained on dive tables. When she saw how much more time was gained diving with a computer vs. the tables all she could think about was getting her own dive computer.

My newly certified daughter will get my old computer as a hand me down. That gives me an excuse with the wife to go out and get a new one.

 

[3D diver]

It depends on the kind of diving you'll be doing and who you'll be doing it with.

I've been shore diving since '81 and bought my first computer a few weeks ago.

Two dives a day, 50 feet or less, with aluminum 80's---who needs a computer? Depth guage, watch/bottom timer & knowledge of the tables is all I've ever needed.

My most recent dive was different though---3 planned dives, high volume steel tanks, >70ft anticipated depths and buddies with all the latest bells and whistles. So I pony-ed up and joined the 21st century. I got a few more minutes bottom time, was able to dive the same profile as my buddies, and got a thermometer too!

 

[dmeeve]

Also + 1 on dive computer. In addition to many of the benefits already mentioned, I enjoy looking at my dive profile on my pc.

I would recommend a watch and depth gauge over a computer. Not just to save money but to reduce your dependency on something that can quit on you if the battery fails

Can't the battery on your watch fail? Spring on a wound watch?

If you do not rely on the computer to do your thinking for you then you will be paying more attention to your gauges

My computer doesn't "think" for me, it calculates and displays useful information. Like a watch, gauge or table.

 

[mala]

If you do not rely on the computer to do your thinking for you then you will be paying more attention to your gauges. When the dive profile called for it I would carry tables.

rich
i carry a bottom timer ,wet notes and a computer(2 sometimes)

one gives me some information and one gives me all the information.

go figure.


welcome to the 21st century.

x

 

[Rich Keller]

A dive computer would increase the margin of safety since they calculate your bottom time and nitrogen loading on actual depths dived even at multiple levels. The dive to this depth and calculate NDL time is less accurate since it assumes all your time is spent at a single depth. A dive computer would calculate that you spend 'x' time at 65 feet and when you ascend to 45 feet you get the extra time instead of assuming you are still at 65 feet.

As for the battery failing, they can't fail in a watch too? I have a watch that has been sitting in my drawer for over 6 months because I'm too lazy to take it and get the battery changed. Since the battery is dead it doesn't tell time. If you are concerned about the battery dying on your dive computer pay attention to the battery indicator or change the batteries before your big vacation.

Besides, how much space can the tables take up? I generally keep a set in the dive bag just to have on hand. They are good practice to dive plan especially when with my daughter to get a ballpark for how long we expect to dive. The actual dive is timed by how fast we use our air. Since we are 65 ft or shallower we will run out of air before we flirt with NDL's.

---------- Post added May 15th, 2012 at 02:28 PM ----------


My newly certified daughter will get my old computer as a hand me down. That gives me an excuse with the wife to go out and get a new one.

I am not saying a computer is less accurate, it is more accurate then the tables, that in my opinion is the problem. The computer will give you a more accurate nitrogen loading reading for a particular body type then tables designed to calculate your whole dive as if it were done at your maximum depth for that body type. This will reduce your margin for error as it is bringing you closer to the real limits. A computer can only be calibrated to one body type and if you are not that body type then you are reducing those limits even further. When I go out on a charter boat I am not seeing too many people that I would consider to be in shape, me included, and I have never seen a dive computer marketed to a 50+ out of shape guy or your daughter. Watch batteries fail too, I use a self winding watch myself, but anything can fail. My point is the watch and depth gauge are far less likely to fail then a computer. A good rule of thumb when I started diving, back when you had to avoid being stepped on by a dinosaur on your way to the water, was that if you stayed at or above 60' with a 72 cu/ft tank you would run out of air before you could get into any decompression problems.

 

[Rogersea]

First, I will preface my response with I am providing you "my"personal opinion.

IVO the fact that you are thinking of purchasing a $30 divewatch to safely track your bottom time(BT). I would consider another sport. The device you choose to track your BT is one of the fundamental devices which allow to dive safely,if you are going to be soooooo cheap that you are not willing to get aresonably good one as your primary BTer, it is my experience that you willadopt that mentality in every safety related decision.

If on the other hand you will consider purchasing a higherquality timing device, then there is nothing wrong with using a watch andtables. In this scenario I wouldrecommend using the eRDPml which is a calculator like device which allows to veryeasily plan multi level dives and helps extend your BT. I would also invest in a standard set of tables.


It was not my intent to harsh or a smart ess. I am just being as straight forward as I can be on this important issue.
Cheers,
Roger

 

[TMHeimer]

It all gets back to both watch/tables and computer are good so why not have both? I had my $54 watch crap out on me once at 70' (freak thing, something got caught and pulled out the time setting button). My $30 watch has worked for years. When the watch did stop I signalled my buddy and we ended the dive. If it had happened when diving solo, I am almost never deeper than 30' anyway--so it depends on what type of diving you are doing. On deeper dives I have both--one may fail... The eRDPml IMO has very limited use, other than a tool to understand the model. Unless you actually plan to stay at 100' for 7 mins., 70' for 14 mins. and 50' for 21 mins., it is pretty useless. For gradual ascending dives or dives to this level or that for 2 mins., then up 3' for 5 mins. just follow the computer.

 

[Jim Lapenta]

Dive computers do not make dives safer. Unless the user actually understands the info they're seeing and makes use of it. Many new divers actually take computers and use them to make their dives more dangerous and increase their risk of a deco problem. New computer users will fly their computers right up to the limits in the false belief that they are being safe. Tables for newer divers are much safer. The scenario of seeing something 15 or 20 feet below your PLANNED depth for a properly trained, disciplined diver is going to be observed from that 15 or 20 feet away or they will have PLANNED for such a contingency and have a contingency plan on a slate or in their wetnotes, Having such backup plans is common practice for tech divers. It is not hard, it takes no more time than any good plan, and is just good practice.

You can also use tables for multilevel dives as easily as any electronic gizmo once shown how and you don't have to worry about getting them wet, dropping them in the water, even setting a tank down on them. You can even run them over with your car and they will still work.

 

[cloudflint]

For the cost of a decent watch that I knew wouldn't fail on me or give time incorrectly I was able to buy a low end computer that did the same thing with the advantage of having a depth gauge built into it too! Though I did end up with my Comp plus dive watch and depth gauge just so I had all my gauges backed up.

 

[Rogersea]

You can also use tables for multilevel dives as easily as any electronic gizmo once shown how and you don't have to worry about getting them wet, dropping them in the water, even setting a tank down on them. You can even run them over with your car and they will still work.

This is true. I had been doing this since 86 once I read the old "Decompression in Depth" booklet. But I no longer teach this method.

Cheers
Roger