These days it’s rare for me not to use a tablet as part of my navigation equipment. The fact I can take my tablet with me anywhere in the world and have access to charts on an interface I am familiar with is a great bonus, as well as the ability to comprehensively plan passages from home.
There are, of course, limitations and pitfalls to the use of tablets but, so long as they are understood, these devices can be used to great effect. Here’s my quick list of tips and hints to make the most out of your tablet and stay safe:
Set up tips
- Rotation lock: Turn this on to stop the screen from reorienting when you pick the tablet up or when the boat heels.
- Privacy settings: Ensure location services are enabled for your chosen app. Select ‘allow only when app is in use’ to save battery time but be aware that if the app is closed then it may take a while to re-establish a position when it’s reopened.
- Screen lock: Set your screen lock time to its maximum setting or never. This has implications on battery life but is particularly important if there is a code set to unlock the screen. If using a tablet for navigation regularly it’s better to remove security codes so any member of the crew can access it.
- Battery life: One of the downsides of using a tablet for navigation is its relatively short battery life. Battery life can be prolonged by reducing display brightness, turning off WiFi/Bluetooth connections and only recording the vessel track if it’s essential to navigation. If you use it a lot on deck then invest in a waterproof USB charging point close to where the tablet is mounted so it can be plugged in for the majority of time. Make sure you take plenty of spare charging cables as the ends are susceptible to corrosion and regularly fail.
- Screen brightness: Remember to dim the screen as the natural light fades, this will save battery life and night vision. To maximise night vision, turn the tablet face down or cover it when not needed.
GPS and NMEA
When choosing a tablet for navigation ensure it has an internal GPS – if working with an iPad you’ll need to select one with 3/4G capabilities for this. Some Android tablets have GPS with their WiFi-only tablets as well as cellular ones.
The GPS position provided by the tablet will not be as accurate as that of a plotter using an external antenna and should not be solely relied upon. Always back up your position using visual checks and never use the GPS in your tablet as your sole means of fixing a position – if the tablet is your primary plotter then use an external GPS feed to improve accuracy.
Most navigation apps are now capable of taking an NMEA data feed via WiFi. This is a great way of providing reliable position data, overlaying AIS information and enabling the tablet to be used as an extra instrument screen from anywhere on the boat. Not all apps can take multiple NMEA feeds so think about what it is you most want your tablet to do and then choose the right app for you.