SeaTracker chart — Route, Discover, Voyage
The SeaTracker tab is the nautical chart at the heart of AnchorQueen. The
chart never goes away — when you switch tabs and come back, your zoom and
position are exactly where you left them.

The bottom of the chart has a pill bar with three sub-modes:
Route — Discover — Voyage.
Discover
The default mode. The chart is yours to wander.
harbours, anchorages, dangers, wrecks, light sectors, AIS vessels, marine
life, dive sites, fishing watch, ocean data, Wikipedia articles, and your
own captain's marks.
need.
shows the depth under the crosshair as you pan.
as a dashed line — handy for crossing traffic.
ruler.
Use Discover to learn an area, scout an anchorage, or browse points of
interest.
Live instrument readout
If you have connected an NMEA instrument source (a Wi-Fi gateway or a
Bluetooth pod — see [Settings → Anchor Watch →
Instruments](settings.html#anchor-watch)), the GPS HUD grows a live instrument
section. It appears only while a source is connected; on a built-in-GPS device
the HUD is unchanged.
RETRY (amber), or NO SIGNAL (red) — the transport (TCP / UDP / BLE),
and how long ago the last data arrived. The age keeps counting up if the feed
goes quiet, so a frozen "12s ago" is your cue the gateway stopped sending.
water shoals), wind (apparent or true speed with its angle), and — when
you tap the card to expand it — heading, speed through water, and
sea temperature. Only the values your instruments actually send appear.
scroll as new readings arrive, so you can see the seabed shoaling or the
breeze building at a glance.
Satellite & Hybrid Base Map
You can overlay high-resolution satellite imagery directly under your vector nautical chart layers to get a complete photographic and metric view of coastal waters.

To enable this:
This overlays high-precision soundings and depth hazard lines directly over real-world coastal structures, making it extremely easy to plan entrance channels to unfamiliar marinas (such as the Hurricane Hole Marina in Stock Island, Florida).
Route
Route mode replaces the HUD with the Route Panel at the bottom.
Hybrid A*-APF & Relaxation Cascade
The routing engine operates off the main thread to ensure absolute UI responsiveness, resolving paths in three logical stages:
* Strict Mode: Enforces full draft + safety clearance along the entire route.
* Shallow Mode: If Strict fails, the planner relaxes clearance rules near the endpoints while warning you of potential draft exposure.
* Best-Effort Mode: Relaxes clearance limits entirely near docks to guarantee that a continuous route is generated, rather than aborting with a routing error.
Dock to Dock
At the top of the Route Panel a two-way switch picks how you build the
route:
many anchors as you like; the app routes between each pair.
harbour to that harbour" passage.
In Dock to Dock the panel shows two slots:
by name. You can also tap the location icon to use your current
position, or the ferry icon to drop in the nearest harbour.
A is set. The moment you choose a departure, the destination picker
opens automatically so you can search straight for where you are going.
The picker lists harbours & marinas first, with other places below, and
shows the distance from your current view. Once both docks are set the app
auto-routes between them around the shallows, just like Free-form.
confirm the pick — departure (A) recenters the view just like
destination (B).
departure and destination — the route re-plans instantly.
Captain's Library
The Capt's Routes entry in the side menu opens the Captain's Library —
one searchable place to manage everything you have saved or collected:
editor; swipe to delete. Long-press for the full action menu: View on
Map, Start Navigation, Duplicate, Reverse Direction,
Export GPX, and Passage Plan (PDF) — the printable A4 passage
plan, straight from the list, no detail sheet required.
and anchorage dwell time; the scope button flies the chart to it.
swipe to delete.
(distance, duration, track points). Tap one for the full passage log
with stats and the ETA calculator.
A search box, sort menu, and live result count sit above the list. The
⋯ Advanced menu adds Import GPX and Manage Folders.
In landscape the library opens in the right details panel, so you can
manage routes while the chart stays in view; in portrait it opens as a
sheet.
Voyage
Voyage is active navigation. A single press-and-hold turns a spot on the
chart into a planned passage you then choose to start. Until you've sailed
a few voyages, an on-chart hint reminds you of the gesture.
your finger; hold until it completes.
from your current position (A) to that point (B) around shallows and
land. Tap the pill's ✕ to abandon the plan. If something prevents a
route — no GPS fix, a destination on land, a point too close to the
boat — the pill says so right there.
the distance and estimated time, and the planned path draws on the
chart as a dashed preview line — pan and zoom freely to inspect it.
(your track, waypoint arrivals, and stats) start, the depth and weather
graphs fill in, and nearby chart objects drop at both ends. Tap
Dismiss to discard the planned route; nothing is started or saved.
Because you confirm with Start, a stray long-press never launches a
voyage on its own. Both endpoints are named after their nearest place. If
the boat has moved meaningfully while the card sat waiting, tapping
Start quietly re-plans from where you actually are before navigation
begins, so the route always starts at the bow — not where it was a few
minutes ago.
Already navigating? A press-and-hold while a voyage is running doesn't
start a new one — it proposes inserting a waypoint at that spot and
reroutes from your current position through it, pending your confirmation.
Active Navigation HUD
While navigating, one card sits at the top of the chart with four
tap-to-switch sections:
a cross-track error bar.
remaining, and your position in the route.
type buttons to switch which graph is shown. Wind draws gust as a
fainter dashed line over the wind line, with wind-direction arrows. Each
graph shows live forecast data along the route, waypoint marks, and a
distance scale. A white dot tracks your current position; drag the
graph to scrub a white dot along the route on the chart — it snaps back
to your live position after a moment. Tide shows the predicted
harbour tide height along your route, drawn around a mean-sea-level line
(the curve dips below the line at low water); where tide predictions
aren't available for an area the graph shows a gap rather than a guess.
Use the ‹ › arrows in the HUD header to step to the previous or next
waypoint; a short banner confirms the new target. The minimize button
(⤡) in the HUD header collapses the whole card to a small NAV · WP
chip; tap the chip to bring it back. The place-name badge tucks in directly
beneath the HUD so the rest of the chart stays clear.
The command window at the bottom (depth scrubber + playback controls)
has three sizes — tap its stage button to cycle full → compact →
minimized and back, freeing chart space when you don't need it.
Stopping & rerouting
reads STOP while you navigate. Tapping it asks you to confirm
before ending guidance, so a stray tap can't drop your route.
slides in showing the time and distance you would save. Tap Accept
reroute to switch or Keep current — it also dismisses itself after a
few seconds if you do nothing.
Finding a place
Tap the search icon in the top bar to open the search panel. It has two
tabs:
What Map Search looks through
One search box queries everything at once and groups the results by where
they came from, your own data first:
| Group | What it finds | Where it comes from |
|---|---|---|
| Captain's Marks | Your saved pins, dive sites, and saved articles | On your device |
| Routes | Your saved routes (by name) | On your device |
| Waypoints | Your named waypoints | On your device |
| AIS Vessels | Live ships near you, by name, MMSI, call sign, type, or destination | Live AIS feed |
| Harbours | Marinas and harbours from the bundled database | On your device |
| Seamarks | Charted buoys, beacons, and lighthouses | On your device |
| Places | Bays, islands, towns, landmarks, addresses | OpenStreetMap (online) |
| Harbours (Online) | The worldwide marina/port database — thousands of marinas with facilities, shelter, and approach depth | OpenSeaMap (online) |
| Explorations | Wikipedia articles about places near you | Wikipedia (online) |
Your own data and live AIS appear instantly as you type. The three
online groups join a moment later — they start once you've typed three
letters and the app waits for a short pause in your typing before reaching
out, so it isn't firing off a request on every keystroke. Online results
are cached, so repeating a recent search returns instantly and still
works when you later go offline.
Reading a result
Each row shows the name, a short subtitle (vessel details, route length,
harbour facilities, and so on), and — when the app knows your position — the
distance in nautical miles. A small dashed-square icon means the place
has a known boundary, so flying to it frames the whole area rather than a
single point.
Tap a result (or its → button) to fly the chart there and drop a pin at
the spot, labelled with its name so the location stays marked after the
camera settles. Tap the pin to clear it. Tapping a route result reveals
that route and frames it end to end; tapping a Wikipedia result also opens
its article panel.
Recent searches
When the box is empty the panel shows your Recent searches. Each row
carries a small badge showing who ran it:
to find somewhere, she searches the very same sources listed above, so a
marina she finds lands here ready to tap.
Tap the ✦ Jules chip above the list to show only the places Jules found.
Clear History wipes the recent list and the offline cache.
> All online sources are not for navigation and may be unavailable
> without a connection — your charts, marks, routes, and the bundled harbour
and seamark data always work offline.
Choosing the chart style
The chart style and depth palette are global — pick them once in
Settings → Appearance. Defaults are tuned for
day-time clarity at anchor.
Chart Layers panel
The Chart Layers sheet is where every overlay is switched on or off. It is
organized into five tabs across the top so you jump straight to what you want
instead of scrolling one long list:
the depth-palette theme, the Depth & Bathymetry group (Depth Contours
and Depth Polygons are on by default so a fresh install opens to a legible
bathymetry chart; the heavier Water Depths / EMODnet fill stays off until you
switch it on, and changing the chart theme re-shows the contours and polygons
if you had hidden them), and
the vector base-map sub-layers (roads, buildings, labels, POIs, boundaries).
Start here to set how the chart looks.
(seamarks, borders, maritime zones, traffic schemes, customs, raster
charts) and the offline S-57 ENC stack you unlock by installing a region
(soundings, channels, hazards, seabed).
seamarks, harbour database, weather, and the exploration layers
(marine life, dive sites, fishing activity, ocean data).
AIS API feed (aisstream.io / VesselAPI) with provider and connection
status, and the Fleet (Remote Sync) group — captains sharing live
position through a SafeAnchor remote channel, with a brief showing the
channel name and how many vessels are synced. The feed always starts each
launch on the default aisstream.io provider; VesselAPI is used only as
an automatic failover (if aisstream.io stays unreachable) or when you pick
it yourself, and that choice lasts for the session only — the next launch
returns to aisstream.io. When you pan or zoom, the ships already on screen
stay put while the feed re-subscribes to the new area in the background —
they refresh in place rather than blinking off and back on.
captains broadcasting on the public beacon near where you're looking. They
show on the chart with an amber ring (so you can tell them apart from
your own flotilla, which is teal, and from raw AIS, which has no ring) and
update live while you're zoomed in. A brief shows how many are in view. It
starts off because keeping the live feed open uses data — turn it on when
you want to see who's anchored around a busy bay.
line, anchor history) plus the appearance of the anchor-watch rings,
own-ship lines, and per-mode crosshair colours.
The bolt menu in the top-left corner has Show All Layers and
Hide All Seamarks shortcuts, reachable from any tab.
S-52 Chart Rendering & Local Vector Tiles
At its core, AnchorQueen uses a customized MapLibre GL Vector Compilation Engine designed to provide a highly interactive, 60fps chart experience entirely offline.
* S-52 Day & Night Charts: Conforming to IHO (International Hydrographic Organization) Presentation Library standards, the app translates S-57 ENC feature attributes (depth contours, light sectors, buoys, restricted areas) dynamically using custom styling stylesheets (Nautica Day and Nautica Night).
* Offline Vector MBTiles: Raw bathymetry, land outlines, and marine boundaries are compiled using optimized mathematical simplifications (tippecanoe) into highly compressed, local MBTiles packages (adminland.mbtiles, maritimezones.mbtiles, admin_places.mbtiles). This reduces resident storage from gigabytes of raw GeoJSON down to a few hundred megabytes, preventing out-of-memory crashes on mobile devices.
* Bundled SDF Glyphs: A fully offline Signed Distance Field (SDF) font package covers Latin, Cyrillic, Greek, and Turkish character sets, enabling real-time font rendering at any tilt and zoom angle.
* Keel Sounding Lookups: Tapping the crosshair triggers a local spatial Kd-Tree lookup to query soundings and physical hazards under the cursor. This operation runs off the main thread to prevent map stuttering during fast pans.
Recording a track
Open the Tracking sheet from the chart's action menu to start recording
a track. Tracks are saved as GPX files you can keep, share, or replay later
from Capt's Notebook.
Offline tiles
Open the Cache sheet from the chart's action menu to download a tile
pack for the area you are sailing. With a region installed from the
Store, the area becomes fully offline-capable.
If something goes wrong
or installed the matching region. See Store.
for your draft; nudge the point into deeper water and try again.
endpoints in deeper water.