The Chart Display

Pelorus Nav renders official NOAA electronic charts (ENC) as vector tiles with standard IHO S-52 symbology — the same symbols found on commercial chartplotters and paper charts.

Chart modes

The button in the bottom-left corner (next to COB) controls how the chart follows your vessel. Tap it to cycle through:

• Follow — the chart stays centered on the vessel, north up.
• Course-up — centered on the vessel, rotated so your course is up.
• North-up — north up; the vessel can move across the screen.
• Free — the chart stays where you put it.

Panning the chart by hand always switches to free mode; tap the button to lock back onto the vessel. The button's icon shows the current mode, and it dims when there's no GPS fix.

Two behaviors make the following modes work like a dedicated plotter:

• Look-ahead offset — while you're underway (above about a knot), the vessel doesn't sit dead center: it slides back from center along your course so most of the screen shows the water ahead of you, where the next buoy is, rather than the water you've already crossed. Below a knot the boat returns to center.
• Auto-return — if you've panned away in free mode, a minute of no interaction snaps the chart back to your vessel (and closes any open panels), so a glance at the helm always shows your boat. This is the "Close dialogs & recenter when idle" setting (Settings → Appearance, on by default) — the same one worth turning off while exploring the app ashore.

Instruments

The instrument panel (toggle with INST) shows large SOG and COG readouts, plus a GPS health badge. When the GPS fix goes stale the badge reads NO GPS and the values blank rather than showing outdated numbers. While navigating a route it grows a navigation section — see Following a route.

On phones in landscape the instruments sit in a side column by default; Settings → Appearance → "Landscape instrument layout" can move them to a top bar instead.

A separate small status strip in the bottom-right corner (tap ▲ to expand) shows cursor coordinates, zoom level, and the raw GPS position, source, and update rate — useful for checking that an external GPS is feeding data.

Detail levels

Electronic charts carry far more information than you usually want on screen. The Detail slider (Settings → Appearance) picks the level:

• Base — coastline, depth areas, and major aids only.
• Standard — the working default: buoys, beacons, depth contours, soundings, hazards.
• Standard+ and Full — progressively more labels, seabed detail, and minor features.

Zooming in also reveals more detail at any setting, so "Standard" plus zooming covers most situations.

Layers

Settings → Charts & Layers has checkboxes for optional layer groups: routing measures, restricted and caution areas, anchorages, cables and pipelines, seabed characteristics, depth-contour labels, light sectors, and more, plus the Tides & Currents overlay.

Charted Currents shows the static current arrows printed on the chart itself — notably the Gulf Stream along the US East Coast, with set and drift (e.g. "3.5 kn"). These are long-term averages from the chart, not live predictions; for predicted tidal currents at a station, use the Tides & Currents overlay. The charted arrows are most useful offshore, where there are no prediction stations.

Depth shading (the blue tint bands) is configured on the Appearance tab — set the Shallow, Safety, and Deep thresholds to match your draft, and the chart colors water depths accordingly.

Display themes

Day, Dusk, Night, and E-ink themes recolor the entire chart using the official S-52 color palettes. Night mode keeps the chart readable without destroying your night vision:

The E-ink theme is a high-contrast monochrome palette for e-paper devices.

Finding places

FIND searches the charts by name — harbors, islands, buoys, lights — ranked with nearby results first. It works offline (the search index downloads with each chart region), and typing coordinates offers a "go to coordinates" result instead. Pick a result and the chart flies there.

The map context menu

Right-click (or long-press on touch screens) anywhere on the chart:

• Copy … — copies the tapped position's coordinates.
• Mark waypoint here — drops a waypoint, auto-named after the nearest charted feature.
• Measure from here — a tape measure: tap points to measure range and bearing along a path.
• Route from here — starts route creation with this position as the first waypoint.
• Plot ▸ — manual plotting tools (bearing lines, distance arcs, position symbols) for traditional chartwork.
• Go to… — type coordinates and the chart flies there.