Sea Layers — Privacy Policy

Effective 20 September 2026. Applies to the Sea Layers iOS app (including the Sea Layers UAT beta) published by Synova Pty Ltd. Contact: [email protected]

The short version

Sea Layers never reports where you fish. Your position, your waypoints, your chart view and the places you tap stay on your phone. They are not uploaded, not to us and not to anyone else — not rounded, not hashed, not in aggregate.

What we do collect, if you leave it on, is which features you use: the layers you switch on, the data sources you pick, the screens you open. That is it.

What never leaves your device

• Your position and heading. Sea Layers asks for location so it can draw your vessel on the chart and read depth and temperature where you actually are. That fix is used on the device and is never transmitted. Location is requested only while the app is in use; there is no background location.
• Your waypoints. Names and coordinates are stored in the app's own storage on your device. There is no account and no sync.
• Where you tap. Probing the chart, measuring a distance, panning and zooming — none of these report a coordinate, a bounding box or a camera position.
• Your chart data. Downloaded tiles live in the app's storage on your device.

What we collect

Only while Settings → Privacy → Share usage data is on. It is on by default and you can switch it off at any time.

• How you have the app set up, and what you use. Which layers are switched on and in what order; which data source you chose for each; which delivery regions you ticked; forecast level; basemap; units; whether the compass, GPS marker or temperature breaks are shown; whether you have set a custom colour window. Also counts — how many waypoints, regions or depth bands you have — never their names, values or positions.
• What you did, by kind. A screen was opened. A probe happened, and what answered it: open water, land, a statutory zone, or one of your own marks — never where the tap fell. A measurement was started. A waypoint was saved, from the chart or typed. A zoning rules table was opened.
• Downloads and sync. The size of a download you confirmed, how many steps or cells it covered, and whether a sync finished, partly finished, or failed.
• About the app and the phone. App version and build, which JavaScript bundle is running (an over-the-air update id), the update channel, iOS version, and your device's time zone. Not your device's name, and not an advertising identifier — Sea Layers does not use one.
• An anonymous install identifier. A random id generated on first launch so repeat use can be counted as one install rather than many. It is not linked to you, to an account, or to any identifier Apple provides.
• Approximate location, from your internet connection. Our analytics provider derives a country and city from the IP address your requests arrive from, the same way any website can. This is not your GPS fix and is not the position drawn on your chart; it is typically accurate to a city.

Deliberately switched off

Sea Layers does not use touch autocapture (which would upload the text of whatever you pressed — and a waypoint row is pressed by its name), session replay, feature flags or surveys. There is no advertising, no third-party tracking, no App Tracking Transparency prompt because there is nothing to track, and no data is sold or shared for advertising.

Who processes it

Usage data is sent to PostHog (PostHog Inc., United States cloud, us.i.posthog.com), which processes it on our behalf. Their privacy policy is at posthog.com/privacy.

Events are batched on the device and sent a few kilobytes at a time. If you are offline — which, on a boat, you often are — they queue and go when you have a connection.

The chart data server

Downloading charts means asking our data server for tiles by region, layer and zoom. Those requests carry your IP address and what you asked for, and are kept in ordinary server logs. A tile request says which region you chose to download; it does not say where you are within it.

Beta testing

While Sea Layers is distributed through TestFlight, Apple collects crash logs and any feedback or screenshots you choose to send, and shares them with us. That is Apple's process and is described in Apple's own privacy policy.

Switching it off

Settings → Privacy → Share usage data. Switching it off stops reporting immediately, discards anything queued but not yet sent, and resets the anonymous install id, so a later switch back on cannot be joined to what came before. The app works exactly the same with it off.

Retention

Usage events are kept for as long as they are useful for improving the app, and no longer than 24 months. Server request logs are kept for 90 days.

Your rights

Because there is no account, we usually cannot connect the data we hold to you as a person. If you believe we hold data about you and want it deleted, write to [email protected] and tell us roughly when and where you used the app, and we will do what we can to find and remove it.

Children

Sea Layers is not directed at children and we do not knowingly collect data from anyone under 13.

Changes

If this policy changes materially we will update the effective date above and note the change in the app's release notes.