Navigation & Instruments

This category covers the instruments that help you find your way and monitor your boat underway: marine compasses, chartplotters and GPS units, depth and speed instruments, and related navigation accessories for leisure boats sailing Irish coastal and offshore waters.

A marine compass remains the essential backup on every boat, chartplotter or not – electronics can fail or lose power, and a compass never does. When choosing one, match the card size and mounting to your helm position and make sure it’s compensated for nearby metal and electronics, which can otherwise throw readings off by several degrees. A chartplotter adds real position, route and chart data, and the main decision is screen size versus mounting space, plus whether you need it networked to other instruments via NMEA – buying a unit that supports the same network standard as your other electronics saves compatibility headaches later.

For coastal and inshore Irish waters, a chartplotter with up-to-date charts is a major safety upgrade, but it should supplement, not replace, a paper chart and compass as backup. Depth sounders are worth prioritising in Galway Bay and the west coast generally, where reliable charted depth can vary with local conditions.

Frequently asked questions

Do I still need a compass if I have a chartplotter?

Yes – a compass has no batteries to fail and is the standard backup if your electronics lose power or fail underway.

What does NMEA mean and why does it matter?

It’s the standard that lets different marine electronics (chartplotter, depth sounder, autopilot) share data with each other – matching NMEA versions across your instruments avoids compatibility problems.

How do I stop my compass reading being thrown off?

Mount it away from speakers, engine wiring and other magnetic sources, and have it professionally compensated if you notice a consistent deviation from known headings.