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6 reasons to own a dive computer

Updated: Mar 3, 2023

During my years as an instructor, I realized that only a very low percentage of divers think it's important to have a dive computer.

Many of them take the course with their instructor, who teaches them how to use the tables, but when they get certified and go diving they think that if they go with a guide, they don't need it.

If you are certified as a diver, you must know how to plan your dives.

With dive tables, you must make a plan before you start your first dive of the day, and you must take a depth gauge and a watch into the water to follow that plan.

Otherwise, you should take a dive computer with you.

In the end, it is the diver's responsibility to plan the dive and know that he/she is within the time and depth limits to avoid decompression sickness.

Ultimately, a dive computer is the best way to dive safely, and I will tell you why.


2.1. Safety.


But first… What is a dive computer?

It's a little gadget you can wear on your wrist, giving you the information your dive tables should give you.

And yes, I'm talking about those dive tables that you learned to use in your beginner's course and that you've never used again.

Am I wrong?

Let me explain it to you without going into too much detail…

Both the tables and the computer help you to stay within your time and depth limits when you dive to avoid decompression sickness.

But you know what?

A computer has many more benefits, and I'm going to explain them to you so you run out and buy one as soon as you finish reading this post and never think of entering the water again without one.

The 6 reasons to own a dive computer.

1. Safety.

It is inconceivable that you go diving without knowing how deep you are going, how long you are going to stay, and if you exceed your allowed bottom time limit.

Why? Because you may be at risk of suffering from decompression sickness. I can promise you that this is not a joke.😱

It's no good to go diving with a buddy or a guide who carries one.

Why not? Because he does one dive and you do another.

It doesn't matter if you are buddies, and you go together. His computer records his dive, not yours.

You need to have the information you need to know that you are within the safe limit and reduce the risk.

2. Accuracy.

This is something you don't get by using dive tables.

With dive tables, you plan for a margin, and you have to dive within that margin. So you lose dive time.

The computer tells you how deep you are and how long you have been there. It calculates the allowed bottom time according to these parameters.

In other words, it calculates your dive meter by meter and minute by minute.

This way you get the most out of your dive without exceeding your limit and without having to make a decompression stop.

Remember that you should always make the safety stop at 5 meters for 3 minutes unless you don't have air to do it, or it is not safe because of the conditions.

Always keep in mind that we also depend on air consumption.

So no matter how much the computer tells you that you can stay longer. If the pressure gauge on the cylinder says no, it means no, and vice versa.

3. information.

Apart from depth and dive time, a basic computer gives you other very important and very useful data.

Water temperature. 🥶

You know why you are getting cold.

You can record this in your dive book for future reference and know which suit to wear for example.

Ascent rate.

Knowing if you are ascending too fast on a dive is crucial.

You will no longer have to use the obsolete methods of the past.

No more ascending with the smallest bubbles, or calculating your speed with a watch and depth gauge.

The computer warns you with an audible alarm and a graph, so you don't over speed and ascend from your dive safely.

Allowed bottom time.

This data, on almost all computers, is the largest number you will find on the display.

It reflects the time in minutes that counts down faster or slower depending on whether you are deeper or shallower, respectively.

If this time reaches 0, this is when you will have to make a Decompression stop, because it means that you have exceeded your time and depth limits.

Safety stops.

Whether you make deep stops that you can schedule in advance or the mandatory safety stop.

The dive computer marks your stop (deep stop or safety stop) when you reach the corresponding depth and discounts the necessary time so that you know when you can safely continue to surface.

Decompression stop.

If you have exceeded the allowed bottom time, then this is when you must make the decompression stop.

And yes, your computer tells you that you have to make a decompression stop. It tells you how deep you have to make it and for how long.

Whether you have enough air to make the decompression stop is your problem, not the computers.

Surface interval.

This a very important and useful piece of information.

It is the time you spend on the surface between dives that will determine how long you will be able to stay on the next dive.

As you know, the longer you are on the surface, the more nitrogen you release and the longer you will be able to spend on the next dive at a given depth.

4. Nitrox.

Nitrox or Enriched Air is air with a higher percentage of oxygen, and other factors must be considered when diving with it.

Enriched air extends the allowed bottom time at a certain depth.

But be careful because it also limits the maximum depth depending on the oxygen percentage in your cylinder.

If you have a computer, all you have to do is enter the exact percentage of oxygen you have in the air in your tank.

The dive computer will calculate all the parameters so that you don't exceed the time or depth.

Otherwise, you would have to use Nitrox tables or do the calculation with tedious formulas.

5. Dive log.

All computers save your dive data so you have it all recorded.

Save all the dive data and the vast majority of computers have a device to download it and carry your dive book on your computer or your phone.

This way you don't have to run after the guide to get the data.

You only have to know where you have dived, and the rest you record yourself.

6. Comfort.

I'm sure you've reached this point on your own with everything I've just told you.

You put the dive computer on your wrist and go diving.

You make your dive following the parameters that it gives you, and that's it. Nothing more to do.

And if you like to plan your dives before you get in the water, you can do that too.

On the other hand, imagine going on a diving trip to the Maldives.

A super trip, live aboard to do 3 or 4 dives a day.

To be able to make them you will need to dive with Nitrox, and if you don't have a dive computer it will be very complicated and tedious.

You would have to plan the dives with tables or formulas.

With the dive computer, you just enter the percentage of oxygen you have in the tank, go for a dive, and follow what the dive computer tells you. Super easy.

I hope you find this information useful and that you see that having a dive computer is very important. You shouldn't dive without one.

You can borrow or sometimes rent one, but if you are serious about diving, it is much better to have one.

It is the first thing I would recommend you to buy along with a good dive mask.

Renting a dive computer means that another diver may have used it the day before, and it will count the residual nitrogen from the dives made with it to you, assuming there are dive computers available for rent.

It is an expensive piece of equipment and very easy to lose. That's why many centers don't have them.

In this post, I am talking about recreational dive computers.

As always, if we are talking about technical diving, it is a different story.

Having a computer that can be used for that kind of dive is more than mandatory. We are talking about much more complex models, with many more features and much more expensive ones.

Did I convince you about the importance of a dive computer?

Do you have any other reason why it is important to have one?

Tell me about it.

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