The dive computer can be considered one of the most important pieces of equipment after the regulator of course. But in recent years the days of RDP tables have fallen by the waist side and dive computers have become a standard and almost essential piece of equipment. With that being said there are a lot of different options for dive computers and choices that you as a diver must make to have the computer fit your style of diving. In order to cover what I find are the important features of dive computers we will disregard brands, most brands make all of the styles of computers I will be discussing and will have minor differences in user interface, and algorithms, they will all have the same functions for the most part. In order to cover the topic of computers I will break it down into multiple considerations; price, style, and features.
PRICE: This is usually the first consideration that a diver must make, what price range you are able to afford will vastly narrow or widen your options in computers both in style, features and functions. There is a pretty wide range of prices for dive computers with your entry level computers starting around $300 and your high end computers reaching up to $1500 and plenty of options in between. With the lower cost computers you will usually get a very simplistic design, 1-2 button navigation, basic settings that can be adjusted by the user, and the basic digital display. The high end computers it is very common to have a full color display, bluetooth interface to adjust settings and download dive data, rechargeable batteries, air integration, and a variety of different user customizable settings. Keep in mind that the cheap computer and expensive computer will both provide you with the same information while diving, depth, time, no deco, max depth, temp, etc… Another thing to be aware of is with brands the expensive computer will be using the same algorithm for determining no deco time as the cheap computer.
Styles of computers: There are two basic styles of dive computers and in each of those styles there are sub categories that will affect the price of the dive computer. Every diver will have their preference, and these include Console and wrist.
Console Computers: For these computers you have the option of standard console with a puck and air integrated console.
- Standard Console with a puck: This type of computer is the most commonly encountered in rental departments in dive shops. These are usually entry level pricing about $400-500 because you are getting a pressure gauge with the computer. The configuration includes, a pressure gauge inside of a rubber or plastic boot with a removable puck dive computer, and possibly a compass. These are a standard configuration with the dive computer being completely removable from the unit, they are essential 3 parts, pressure gauge, computer and compass held together in a housing. This is nice to have everything you need in one central location, it is attached to your regulator via the pressure gauge so you can’t forget it and is easy for new divers to get acquainted with the location of pertinent information while diving.
- Air integrated Console: These generally fall into the higher end price of dive computers, $700 and up generally. Like in the name the computer has air integration so there is no more traditional pressure gauge, it is now a digital readout. This make air pressure much easier to interpret than a traditional gauge, with a fairly exact number given. Another added feature of air integrated computers are estimated air consumption. These computers in addition to your no deco time will factor in how quickly you are consuming air and give you a countdown of how much time before you consume all of your air. While this is not a necessary feature it is nice to have that information especially when navigating or making your turn to head back to the shore or boat. The biggest downside to air integrated dive computers is if the battery dies or computer fails the diver has no way of knowing what their air pressure is, this is very uncommon and the computers are very reliable, some divers will have a back up pressure gauge on their regulator for piece of mind.
Wrist Computers: these are popular options for divers that may not be ready to purchase their regulator yet or don’t plan on purchasing a regulator and want a personal computer for travel, there are 3 styles, puck, wrist watch, and Air integrated/Transmitter.
- The puck: this is the cheapest version of a dive computer that can be purchased from any brand, usually in the $300-400 range this is the same puck as the console computer but instead in a wrist boot. A diver could if they wanted to purchase a puck in a console and a separate wrist boot and switch the computer back and forth depending on their diving situation. These are good for divers that want a computer but not all the other stuff ideal for travel and people that don’t want to deal with the regulator. These are very simple 1-2 button navigation through menus and very good option for a diver on a budget.
- The wrist watch: these are dive computers that double as a digital watch, they are generally not much bigger than your standard digital watch, and many are very subtle and fashionable. These types of computers have a wide range of prices because they can vary from very simple to very technical, entry level dive watch computers start around $400 and the high end computers can reach up to $1500 like the Garmin MK2i. Some of these computers are capable of being air integrated using a transmitter, and some are just a smaller more compact version of a puck. If you are a person that likes to ware a watch this may be a consideration offering many different styles and price ranges, many these days will also have changeable wrist straps to customize to the user.
- Air integrated/transmitter: These tend to be the higher priced computers because they have the most features packed into them, keep in mind many of these computers can function as a normal computer without the transmitter, but will the transmitter will allow for air pressure to be displayed on the computer. It is also common for these computers to have full color displays making them very easy to read while diving. There has also been an increase in computers in this category to have rechargeable batteries given that the color displays tend to use more energy than the standard digital displays. Like I said for the wrist watch style there are computers that are small and compact like watches in this category and there are also large blocky computers with large displays in this category, while the wrist watches tend to be slightly higher priced because it is the same tech in a smaller frame. Keep in mind with air integrated wrist computers they do not generally come with the transmitter, that usually has to be purchased separately and the standard price for a transmitter is $400, and they are brand specific, so make sure if you do not purchase them together you get the correct one for your computer.
Features: this is something that at this point in time most computers will share a lot of features as technology improves. Many common features to consider and check weather these features are important to your style of diving.
- Nitrox: This is a very common features and almost all modern computers are Nitrox compatible, usually up to 40%, some higher end computers that are dual purpose, recreational and tech diving will be compatible up to 100%. These will adjust algorithms for higher concentrations of Nitrox. NOTE: no computer that I am aware of will test the air for Nitrox, the diver must test the air separately to get oxygen concentration and enter that amount into the computer manually.
- Dual Algorithms: most dive computers use a single algorithm designated by the brand manufacture, some are more conservative than others reducing the no decompression limit. Some dive computers (Oceanic in all computers and Suunto in select computers) allow the user to chose between more conservative or liberal algorithms depending on their diving style. This is not usually a feature that matters that much but if you find your computer is giving you significantly more or less bottom time than your buddy it might be a feature to consider.
- Display: this is a feature that tends to change with age. As divers get older finding a display that is easily readable becomes more important. Large, or color displays tend to be more important for divers as they progress in age, these features tend to increase the price in computers with color displays on the higher end and larger displays in the mid range.
- Navigation buttons: this is a personal priority of mine, especially after helping students with very basic computers. Dive computers with have from 1 to 4 buttons to navigate the menus and settings. With single button computers you press the button to advance the menu and hold the button to select. This can be tiresome when changing settings and if you miss a setting you have to cycle completely back around. Two button navigations are more common in newer computers and have an advance and select button reducing the likely hood of accidentally skipping the setting you want. Three button computers are generally higher end computers that have advance, select and back buttons making navigation very easy. Most 4 button computers are wrist watch style with the 4th being a backlight, and some computers like the Oceanic ProPlusX, and the Atomic Cobalt that have more elaborate menus.
- Alarms: the amount of alarms a computer has will depend largely on how much integration it has, it is common for basic non integrated to have depth, time, and no deco alarms. While an integrated computer will also have air pressure alarms and time remaining alarms. All of these can be turned off and adjusted for personal preference.
- Battery: this is a feature that many don’t think of until its time to change the battery. There are 3 different types of computers when it comes to battery, user changeable, manufacture change and rechargeable. Most high end computers will be rechargeable, while more basic computers are now more commonly user changeable especially the puck computers. Many of the wrist watch computers are manufacture battery change and will often require pressure testing after the battery is changed. Be aware of the method your computer will be and if it is user changeable make sure you have the right battery as a spare, most puck computers use the CR2450 coin computers, this is the most common.
- Digital Compass: this is something that is usually only found in higher end computers that have the intention of simulating the traditional compass and reduce the need for additional equipment. Digital compasses are fairly accurate, but usually need to be calibrated before hand and if you haven’t will be less useful. I find this to be a nice feature but despite having it on a couple of my computers past and current I don’t generally find myself using it and prefer to rely on a more traditional compass.
I hope this is useful for any divers considering purchasing a computer, weather it is a replacement for an old outdated computer or their first computer. Computers are very important pieces of equipment that I believe all divers should have.