Watch an experienced skipper use a marine GPS and the surprising thing is how little they look at it. The screen tells them where the boat is; everything else comes from the chart, the depth, and what is visible out of the window. Navigating like a professional is mostly that habit, and it can be learned in a season. Here is the order I would learn it in.
What a beginner actually needs to learn
- Your position, course and speed, and where each is displayed on your unit.
- How to drop a waypoint and run a route to it without improvising at sea.
- How to read depth contours, buoyage and hazard symbols on the chart.
- Two features worth switching on early: AIS and the anchor alarm.
- A backup, and the habit of cross-checking your fix against it.
- 1 Step 1. Learn what each screen is telling you
- 2 Step 2. Set a waypoint and run a route, at the dock first
- 3 Step 3. Read the chart, not the boat icon
- 4 Step 4. Switch on the two features people ignore
- 5 Step 5. Choose the app once you know what you need
- 6 The habit that separates a pro from a beginner
- 7 Before you leave the dock
- 8 Three questions beginners ask
Step 1. Learn what each screen is telling you
A marine GPS, short for Global Positioning System, calculates your position from satellite signals and overlays it on a nautical chart. Every unit and app organises the same core information slightly differently, so the first job is finding it on yours: position, course over ground, speed over ground, and the depth reading if a sounder is connected.
Course over ground is where beginners get caught out. It is the direction the boat is actually travelling, which in any tide or crosswind is not the direction the bow is pointing. Comparing the two tells you how much the water is pushing you sideways, and that single comparison is worth more than any other number on the display.
Step 2. Set a waypoint and run a route, at the dock first
A waypoint is a saved position. A route is a chain of them. Learning to create both while tied up, with a coffee, is far easier than working it out in a lumpy sea with a family asking when you will arrive.
Practise this sequence until it is automatic: drop a waypoint on the chart, name it, build a route from your berth to it, start the route, and read off the bearing and distance to the next point. Then delete the whole thing and do it again. Ten minutes on the pontoon covers roughly ninety percent of what you will ever do with the device.
Step 3. Read the chart, not the boat icon
Nautical charts show water depth, the nature of the bottom, buoyage, lights, and hazards such as submerged rocks and wrecks, along with tidal and magnetic information. The GPS puts an icon on that chart. It does not interpret it for you.
Three things to learn early: depth contours and how to set your unit’s safety depth so shallow water is shaded clearly, the buoyage system used in your region, and the abbreviations for bottom type, which matter the moment you want to anchor. Plenty of resources exist for this, from online tutorials to classroom courses, including those run by the Coast Guard Auxiliary in the United States.
Step 4. Switch on the two features people ignore
AIS, the Automatic Identification System, is a tracking system used by ships and vessel traffic services that broadcasts a vessel’s position, course and speed. On your display it turns nearby commercial traffic from a distant grey shape into a named target with a heading, which is genuinely reassuring the first time you cross a shipping lane at night.
The anchor alarm is the other one. You set the position where the anchor went down and a radius, and the alarm wakes you if the boat leaves that circle. Set the radius generously enough to allow for swinging with the tide, or you will spend the night silencing false alarms and eventually switch it off, which defeats the point.
Step 5. Choose the app once you know what you need
A smartphone or tablet running a proper charting app is a capable navigation tool, and for many boaters it is the primary one. The main options differ less in charts than in how they are sold and how far you can customise them.
| App | Suits | Worth knowing |
|---|---|---|
| Navionics Boating | Most recreational boaters | Owned by Garmin; subscription covers daily chart updates, sonar-derived depth maps and dock-to-dock auto-routing |
| iNavX | Offshore and serious cruising | Takes charts from several providers and connects to external GPS and instrument feeds; tiered subscriptions |
| Wavve Boating | Inland and coastal day boating | Built around simple route planning and points of interest rather than depth of configuration |
If you are buying a fixed chartplotter rather than using a tablet, the questions are slightly different: screen readability in direct sun, waterproofing, and whether it will talk to your other instruments over Bluetooth or Wi-Fi so that depth, wind and AIS data all land on the same display.
Whatever you choose, download the charts for your area before leaving, not at the fuel dock. Mobile coverage offshore is the first thing to go, and an app that streams its charts is an app that goes blank exactly when you need it.
The habit that separates a pro from a beginner
The Royal Yachting Association’s guidance on electronic navigation makes the point plainly: it is vitally important to have an alternative means of fixing your position and navigating to safety, ideally on a system that keeps working if the primary one fails. The RYA also teaches students not to rely on any single method of fixing a position, and to cross-check constantly by another technique.
That is not nostalgia for paper. Electronics need power, need a satellite signal, and can fail, and the failure modes are rarely dramatic: a flat tablet, a wet connector, a phone that overheats in the sun on the console. A handheld GPS in a locker with its own batteries, a compass, and a rough idea of your position kept in your head all cover that gap.
Before you leave the dock
- Charts for the area downloaded and up to date on every device you plan to use.
- Route entered, with the safety depth set for your boat’s draught.
- Devices charged, and a charging cable that actually works aboard.
- Backup available and reachable, whether that is a handheld unit, a second device or paper.
- Someone ashore told where you are going and when you expect to be back.
Three questions beginners ask
Is a phone app good enough on its own?
As a primary tool on coastal day trips, for many boaters yes. As the only tool, no. The weak points are battery, waterproofing and screen visibility in bright sun, not the charts.
Do I still need to learn traditional chartwork?
Yes, at a working level. The RYA now teaches electronic navigation as the primary method with chartwork kept in the syllabus as the backup skill, which is a fair description of how most people actually navigate.
How do I keep the unit accurate?
Update the charts and firmware as the manufacturer publishes them, check the settings after any update, and compare what the screen says against a visible landmark or buoy whenever you get an easy opportunity.
Fitting out the rest of the boat?
A plotter is one item on a longer list, and a sounder built into a fish finder covers more than fishing.
Last updated: 5 August 2026. App features, chart coverage and subscription terms change regularly: confirm current details with each provider before buying. Guidance on backup navigation is summarised from the Royal Yachting Association’s published advice on electronic navigation aids. Carriage requirements for navigation and safety equipment are set nationally and vary by vessel size and area of use; check the rules that apply where you sail, and take formal training before navigating unfamiliar or offshore waters.