While many different smartphones will work aboard a boat, there are certain features that can significantly increase function and make things run more smoothly.

We consider them requirements, and so we compiled a list that can act as a primer on how to buy a smartphone for marine applications. If you are looking to purchase a new phone, we suggest you consider the list while comparison shopping. If you already have a phone, it may help you decide whether to keep it or look for a new one.

• Sunlight Visible Screen. When on your boat you will often find that you want to use your smartphone outdoors, so it is very important that the screen be visible in direct sunlight. If you are considering a specific smartphone, be sure to take it outside and test it. We have gotten more than a few funny looks when doing contortions to shade the screen while on our dinghy with an inadequate screen.
• GPS Connectivity. To use your smartphone as a navigation device requires connection to a GPS. We prefer a smartphone that has the GPS built in, and in fact this is becoming more and more common. It's one less device to mess with, to charge up and to worry about dropping overboard. The alternative is to connect an external GPS via Bluetooth. We have actually done this for several years with our various devices and it works quite well. One warning: not all Bluetooth interfaces or smartphones will connect to a GPS. Make sure that the Bluetooth on the smartphone you are considering has SPP (Serial Port Profile) support.
• Tethering Capabilities. Being able to tether your smartphone to your laptop to facilitate an Internet connection is a great capability. It can save you money and works quite well. We would not consider a smartphone that did not support tethering, but if you regularly use an aircard then tethering may not be important to you. (For a story on tethering, see link.)
• Touchscreen. We believe a touchscreen is the most intuitive way to interact with a smartphone. This is particularly true if you want to run a navigation program. Interacting with the maps and charts directly on the screen is simpler, and many programs, such as TomTom, Pathaway and our own ActiveCaptain Mobile require a touchscreen.
• External Antenna Connection. One extremely useful upgrade is to connect an external antenna and amplifier to your phone. Smartphones with external antenna jacks make the connection to an amplifier better and make full amplification possible. There are ways to amplify a smartphone with a cradle, but this will cause you to lose some signal strength.
• Keyboard. Keyboard preferences are a very individual thing. They can be based on many factors: past experience, typing abilities, finger size and how much typing you plan to do. Jeff is a fast, touch typist. Karen is a hunt-and-peck user. But we both agree that you are probably better off with a physical keyboard, than an on-screen "soft" keyboard. It is just hard to replace the tactile feedback of physical keys. So if you are that type of user who does a lot of typing, we strongly suggest a physical keyboard – and be sure to try the keyboard yourself. The perfect setup for one user could feel clumsy to another.
• Size, Weight and Form. It is important that you actually touch the smartphone you are considering. While much can be learned by looking at reviews from other users, nothing beats a hands-on trial. How does it fit in your hand? Will it fit in your pocket? There are trade-offs to be made on features verses size and weight, so you will have to decide which work best for you.

Of course, as with most things in life, one size does not fit all when it comes to phones. Much depends on what is important to you. Maybe you just want quick and easy access to email and don't care about using a tide program. Or maybe you are set on using the latest navigation software, and email is not important. All will influence the platform and model you choose – and how much you spend.

Many mobile carriers offer a 30 day return or exchange policy if you're not happy with the phone you choose, but some do charge a restocking fee. Be sure to check with your provider for details on their return policy.

Another important consideration is the availability of software. If there is a feature or function you deem an absolute requirement, whether it's a sophisticated navigation program or simply a really good Scrabble game, be sure the software is available for the device you are considering. You can look on the Handango website, or ask on the Mad Mariner Technology Forum.

Based on software availability and your hardware needs, you can then create a list of smartphones that may suit you and check them out first hand.