While much has been written about how to choose navigation software, how to buy the onboard computer that runs it is a topic that is too often ignored.

Thankfully, purchasing a computer is something most of us have done, and buying one for the boat is much like buying one for your home or office. You want a fast machine with plenty of processing power, memory and storage for files.

Of course, there are some special needs to address and some traps to avoid. But if you adhere to the guidelines that follow and do some comparison shopping, you should be able to find an extremely capable machine for $1,200 to $1,500 – and dodge some major problems in the balance.

Like all marine purchases, the equation starts with assessing your needs. For our purposes, we will assume that the primary goal is to run software that can view electronic charts, either to plan trips, navigate or both.

You may want to do other things – access email, keep a log, check out web sites or watch DVDs – and a computer can facilitate all of that. But let's assume for now that navigation is the primary objective.

BUY A NEW MACHINE

The first important piece of advice is that you should commit to buying a new machine, unless you have a computer available that was purchased in the last three months. Done properly, this strategy will give you the latest technology and minimize the amount of time spent troubleshooting.

A laptop on board has become a common sight.While it may seem thrifty to rehabilitate an old machine and press it into service, or buy a used one on eBay, this is often a false economy. Computer technology changes fast and modern navigation software is demanding. Upgrading or buying used may be cheaper than buying a new machine, but that savings can quickly be offset by the amount of time spent troubleshooting the installation.

A better strategy is to spend that time shopping for a bargain on a new machine, which will almost always be better matched to the task. You can then take that old machine and use it to read email and play DVDs, protecting your new navigation computer from viruses and other problems associated with heavy Internet use.

There are, of course, boaters out there with a technology background who are capable of making magic with old hardware. The rest of us should buy new.

CUSTOM ORDERS

The second important piece of advice is that you should order your new machine – whether laptop or desktop – directly from a manufacturer such as Dell or Lenovo, and have it built according to your specifications. While this may sound like an expensive custom solution, that is usually not the case. Computers are commonly purchased on a custom basis, either by phone or online, and the prices are competitive with off-the-shelf models.

The benefits are simple: you get exactly what you want and avoid some things you don't.

When ordering a machine, you generally start by selecting a base model and then adding upgrades on an a la carte basis. For example, an IBM ThinkPad T61 currently costs $964 for a machine with 1 gigabyte of RAM. But for another $80, the same machine can be bought with 2 gigabytes of RAM.

Start by shopping online and identifying models you like. There are literally dozens of web sites you can visit to read primers, reviews, tips and recommendations. CNET.com, ConsumerReports.org, Epinions.com, Gizmodo.com, PCWorld.com and About.com are just a few. Much of this reading is worth your time. Just realize that many of these sites are proffering information about the latest and greatest for a tech-savvy audience – not for boaters. You may not need everything you read.

When you have it narrowed down to two or three machines, call one of the companies or go to its web site and get an quote with the options you want. The company will generally email you an estimate that is good for several days; to buy, you either click a link or call with an order number. You can repeat the process to comparison shop, and then choose your best deal and execute the transaction.

If you want to see the machine in action before you buy, you can test one at a local store. But make sure you are trying the exact model you want – and try to avoid buying it there. Machines offered by retail chains like Best Buy, Circuit City and Staples certainly can get the job done, but they are often loaded with unnecessary features and trial software – commonly called bloatware – that can slow your computer and cause compatibility issues. A custom machine will eliminate all of that – just be sure to ask that the computer be delivered clean.

Off-the-shelf machines also come as preconfigured packages that make it tougher to get exactly what you want. The a la carte approach is far more flexible, and you only pay for what you need. Order your machine. It's what the pros do.

Buying a new machine and ordering in on a custom basis can avoid a great deal of troubleshooting. LAPTOP VERSUS DESKTOP

While this issue can be a big one on land, that is usually not the case onboard a boat. You almost certainly want a laptop.

Laptops are a bit more expensive than desktops, but they are competitive in terms of features and they have become the industry standard when it comes to onboard machines. The ability to go portable and use the machine anywhere trumps almost any argument against it. With the right battery and some attention to charging, a laptop will allow you to do navigation work in the saloon, stateroom or at multiple helm stations. You can also take it home to plan your voyages, or use it aboard a charter or a friend's boat.

Laptops can be difficult to mount, leaving most boaters to simply use them on the nearest flat surface. But there are solutions for those who insist on a hard installation. Companies like RAM Mounting Systems make special hardware designed to hold a laptop in place at the helm (see link). Laptops also have ports to add an external screen and mouse, which can be mounted at the helm while the computer sits out of the way.

Of course, there are some boaters who may benefit from desktop machines, particularly those with large vessels who have opted for expensive PC-based navigation electronics.

Desktop machines do offer more flexibility to work on the computer, adding upgrades or fixing broken parts. While most laptops are closed systems, with components packed tight in the factory to achieve portability, desktop machines are designed to be manipulated by their owners. Manufacturers assume the user will "crack the case" in order to add a graphics card, a modem or some other component. The result is that desktop machines have wiring and expansion bays to accommodate additional drives and other upgrades – and room to work within the machine – that can be extremely helpful in some applications.

But for most boaters who want to connect a computer to a GPS and a few other instruments, then plan trips and navigate using standard electronic charting software, a laptop is the best solution.

MAC VERSUS PC

There are entire tomes to be read about the advantages and disadvantages of owning an Apple versus a PC and this debate is apt to continue long into the future. What is important to remember when buying an onboard computer is that everything that is true on land is also true at sea.

A Mac is an elegant, easy-to-use machine that is generally more stable than Windows-based machines and has little trouble with computer viruses (the bad guys don't write viruses to attack the Mac's operating system).

It also has a smaller support network and far fewer software offerings to choose from. For example, if you own a Mac, there are only two major navigation software packages available: NavimaQ and MacENC. If you own a PC, there are perhaps a dozen. Similarly, you can get a PC fixed almost anyplace you go, but finding an Apple store may be more difficult.

If you are weighing this decision, you might let familiarity be your guide. If you are already a Mac person, then taking a Mac onboard probably makes sense. It's a great piece of gear and you'll spare yourself the learning curve. Similarly, if you are a PC person, you may want to stick with the PC. Even if you have an interest in switching platforms, your boat is probably not the place to do so.

If you use both and you are in a quandary, go with the PC. You'll have more options, more support and you'll be in line with what most boaters are using.

BRAND NAMES

Let's assume, for the time being, that you are now in the market for a new laptop, a PC that you will be buying on a custom basis.

One of the first questions you will confront is whether to buy a marinized computer. Companies such as Marine Computer Systems, Argonaut, AR Engineering and Group Mobile offer machines that are built for marine use. Desktop models offer soldered wiring and watertight connections in a very small unit. Laptops have ruggedized casings that are designed to absorb shock. This is all good stuff – if you can afford it. The truth is that a marinized or hardened laptop can cost thousands of dollars more than a normal machine, and many electronics experts say they are simply not worth the expense.

If you decide to go this route, your strategy will not change much. You will still be buying a new machine on a custom basis according to specifications you supply. The difference is that you will be dealing with a company that knows boats – and spending a lot more. However, unless you have some special circumstances, there is no need to incur such expense. An equally good strategy is to buy a solid, everyday laptop and take good care of it.

There is, of course, the question of which brand to buy. Here you will get much advice, because everyone seems to have something they favor and something they disdain. The reality is that brand names matter far less when it comes to computers than they do in the rest of the boating world. If you have a favorite brand that has served you well, then stick with it. If you had a bad experience that caused you to shy away from a particular brand, then respect that too.

If you don't have either of these experiences to draw upon, then let your research be your guide. If you find the right combination of features for the right price, then don't spend time worrying whether it is or is not a Dell. If it's a common brand – Dell, Gateway, IBM, Lenovo, Toshiba, Sony, HP and a few others – you should be fine.

THE RIGHT STUFF

The reality is that the utility of your computer will rise and fall on the components within it, particularly the CPU or central processing unit, which allows the computer to run its applications, and the amount of RAM or random access memory, which allows it to store programs and images for ready use. Other components that play a role include hard drive(s) that store information; a graphics card that processes images quickly; USB and other ports that allow connection to outside devices; and the screen everything displays upon.

Modern navigation software is graphics heavy, drawing upon raster and vector charts, topographic maps, satellite images, photos, and bathymetrics. What you are looking for is a machine that can process all this at speeds that will accommodate smooth usage, without having to wait for files to open and features to work.

What follows are some guidelines for various components. They are not hard and fast rules. Rather, they are parameters that should help you shop. Note that these suggestions apply only to PCs; different parameters apply to the Mac.

While technology is constantly changing, a well-appointed machine costing $1,200 to $1,500 will have a 2.0 gigahertz, dual-core processor by Intel or AMD. A dual core processor is actually two processor units working in parallel and it has become the standard in CPU technology. You can buy faster processors, but a dual core in the neighborhood of two gigahertz should serve you well without breaking the bank.

Another concern is the operating system. While this is technically software, it is traditionally purchased with the computer and pre-loaded at the factory for a new machine. Unless you are using a Mac, you will be running Microsoft's Windows (many technical pros prefer Linux, but there are no mainstream navigation programs currently offered for Linux). The latest version of Windows, which was released in 2007, is called Vista and this is what you will find on almost all new store-bought PCs.

For a navigation computer, this can be a problem. Because Vista is relatively new, not all navigation programs are compatible. They will be eventually. This is Microsoft's new platform and almost all programs will eventually support it. However, you can expect quirks for the next year or so as software manufacturers make the change. The best strategy is to order your machine with Windows XP Pro. All mainstream navigation programs run on XP and you can later upgrade to Vista yourself, with an easy, single-disk installation.

You will want to spend the extra money it takes to get 2 gigabytes of RAM, which is enough memory to insure that programs operate smoothly.

GRAPHICS AND SCREEN

A video card can be one of the most confusing components of a computer, but choosing the right one can have a dramatic impact on performance, particularly when working with graphically intensive applications like navigation software. Many times your choice of brand and power will be limited by your computer's manufacturer, which will traditionally offer "good", "better", and "best" options. Video cards on the lower end of the scale usually include an integrated graphics processor that shares your system's memory. If you can, go with a video card with dedicated memory, and the more memory the better. The high-end cards cost more and consume more power, but offer much higher performance.

In terms of screen real estate, bigger is better. Buy a computer with the largest screen you can find because it will be more than occupied by charts and other applications. On most medium-priced laptops, you can expect a 15-inch screen and you should consider this the minimum. Many laptops now sport 17-inch screens, and a few even go up to 20-plus inches, if you're willing to pay for them.

Storage, meaning the size of the computer's hard drive(s), is less important than it once was, because external drives are now large and affordable. However, externals may be slower than the machine's native drives, and so you want as much storage as you can afford built into the machine. A laptop with 80 gigabytes is sufficient, and 100 gigs or more is preferable. Another factor is the speed of the drive(s), which is measured in revolutions per minute. Drives of 4,500 RPM are acceptable, but 7,200 RPM is better.

Additional drives, such as a CD or DVD drive, are often debated by users on land because they add weight to a machine. For an onboard computer, however, a DVD drive is worth the weight. You will want a DVD drive because many navigation programs and charts load from DVDs. Again, you could add an external drive later, but it's better to get it built in, if you can.

One thing that is easy to forget is the number and type of ports. Virtually all machines come with several USB ports; an Ethernet port for high-speed Internet access; and connections for an external monitor and mouse. But if you require more ports, or something special, make sure it is included on your machine. For example, you might want a Flash card reader or you may have an Internet air card in the older PCMCIA Card format. If you want to make use of these devices, make sure that your machine has the ports built in.

A USB air card provides easy Internet Access.BATTERIES AND PERIPHERALS

Battery life is another parameter that deserves your attention. This is one area in which reviews can be helpful, especially those that actually test the machines. Pay attention to reviews that track real performance, not just the manufacturer's claims.

If battery life is important to you, meaning you plan to use the computer for long amounts of time without AC power, then consider buying a larger battery and using the stock battery that came with the machine as a spare.

There are also some peripherals that are best bought separately, because they will be cheaper.

Be sure you buy security software, such as Norton or McAfee, as soon as you start using your machine, to protect against viruses. You can also run programs like Ad-Aware and Spybot, which protect your computer in different ways. Both have free versions, as well as more full-featured applications that require payment (see links).

In order to take advantage of most navigation software, you will want an external mouse with a scrolling wheel, which you can buy in a wired or wireless configuration. If you plan to use your computer for real-time navigation aboard your boat, you will need a GPS that plugs into a USB port. Two reliable units are the GlobalSat BU-353 or the Garmin GPS 18.

You may also want an air card, which you can get through mobile providers such as Cingular or Verizon. These devices plug into a USB port and function like a cell phone to provide high-speed Internet access. Finally, be sure to buy a padded case for your machine – it's worth the money.

Glen Justice is the Editor of Mad Mariner.