PBDNA · Quick User Guide

AnchorGuard

A practical guide to planning an anchorage with location, weather, bathymetry, terrain, and offline regional data.

Safety first: AnchorGuard highlights risk factors; it never declares an anchorage safe. It is not a navigation product. Always use official charts, notices to mariners, current observations and forecasts, local knowledge, and prudent seamanship.

1. Quick start

  1. Choose Current GPS or Plan a location.
  2. Place or search for the location you want to assess.
  3. Set the Analysis radius from 1 to 25 km. The circle controls terrain, coastline, anchorage, and weather sampling.
  4. When connected, choose Analyze with live weather. AnchorGuard samples weather across the selected area.
  5. Review official alerts, the risk index, risk breakdown, anchorage geometry, and terrain funnel information.

A larger radius adds regional context; a smaller radius focuses on immediate surroundings. Select the radius appropriate to the planning question—not simply the value producing the lowest score.

2. Choose a location

Current GPS

Use the device’s position for a nearby assessment. If prompted, allow location access while using AnchorGuard. GPS accuracy and availability depend on the device and surroundings.

Plan a location

Use the planning map to search or drop a pin. Confirm the displayed coordinates and scan radius before analyzing. Recent planning locations are retained on the device for convenience.

Live versus offline

Live weather indicates that current Open-Meteo data was loaded. When supported, active National Weather Service advisories are incorporated into the weather score.

Offline estimate uses information already available to the app and should be treated as a planning estimate, not current conditions.

3. Read the results

Risk index
A 0–100 summary intended to draw attention to contributing factors. It is not a safe/unsafe declaration.
Terrain · up to 40 points
Relief, slope, channel shape, and wind alignment around the selected area.
Weather · up to 40 points
Wind, gust difference, pressure, inversions, climatology, and applicable official advisories.
Anchorage · up to 20 points
Exposure, holding assumptions, depth, swing room, seabed geometry, and nearby hazards.

Anchorage geometry

When a regional bathymetry pack is available, AnchorGuard reports modeled depth, the depth profile within the radius, seabed slope, and source coverage. These values are regional model data and must not replace official charts or direct soundings.

Terrain funnel

When a terrain pack includes land inside the circle, AnchorGuard estimates local relief, land slope, land coverage, and a possible terrain-channel axis. Alignment can indicate where terrain may influence wind, but it does not forecast a particular gust or williwaw.

No land within the scan

An installed terrain pack can be working normally even when an offshore scan circle contains no modeled land. Increase the radius or move the pin closer to shore if surrounding terrain is relevant.

4. Prepare offline data

  1. While connected to the internet, tap the drive icon at the top right.
  2. Find the bathymetry and terrain regions covering the intended cruising area.
  3. Tap Download and wait for Available offline or Installed.
  4. Before departure, reopen Offline Data and verify every needed region remains installed.

Downloading a pack makes the regional model available locally. Current weather and official-alert checks still require connectivity.

5. Troubleshooting

Current GPS does not return a position

Open Settings → Privacy & Security → Location Services → AnchorGuard and permit access while using the app. Move where the device has a clearer view of the sky, then try again.

Live weather does not load

Confirm internet access, retry the analysis, and verify that the coordinate is valid. If live data remains unavailable, AnchorGuard labels the result as an offline estimate.

A pack says installed but no detailed result appears

Check that the pin is inside the pack’s coverage and that the scan circle contains the relevant land or water cells. Try a larger radius. You can also use Check & Update in Offline Data.

Need more help?

Visit pbdna.net/anchorage-risk. Include the device model, iOS version, app version, selected coordinates, radius, and a screenshot with a support request.

6. Data and limitations

  • Bathymetry is derived from the GEBCO regional grid, assembled from sources of varying resolution and quality.
  • Terrain analysis uses Copernicus GLO-30 elevation data and is calculated locally from the downloaded model.
  • Live weather uses Open-Meteo; official alert availability varies by National Weather Service coverage.
  • Model cells may differ from present local conditions, charted hazards, shoaling, construction, or temporary restrictions.
  • The person in command remains responsible for navigation, anchoring decisions, watchkeeping, and response to changing conditions.