Datenschutz
What leaves the phone
This page describes how the True Helm Android app and this website handle data. It is written to be read, not to be survived.
Last updated: 6 October 2026 · Applies to True Helm for Android, version 1.0
The short version.
- There is no account and no sign-up. The app never asks who you are.
- There is no server behind the app. Your positions, tracks and recordings are written to the phone's own storage and stay there.
- There is no analytics, no advertising, no crash reporting and no tracking code of any kind in the app.
- The one thing that leaves the phone by itself is a map tile request while the chart is on screen and switched on — and only then.
- Everything else leaves only when you tap SHARE yourself, to a place you pick.
What the app processes
True Helm is a sailing instrument, so it necessarily works with data about where you are and how you are moving. All of the following is processed on the device:
| Data | Where it comes from | What happens to it |
|---|---|---|
| Position, speed, course, GPS accuracy | The phone's GPS receiver | Shown live; written to a track file and a logbook file while you are recording |
| Compass heading, magnetic field strength | Rotation-vector and magnetometer sensors | Shown live. Not stored |
| Heel angle | Accelerometer | Shown live. Not stored |
| Display preferences, such as which heading the DATA tab shows or whether the chart is switched on | Your own taps | Saved in the app's private settings so the choice survives a restart |
The app collects no name, e-mail address, phone number, contact list, device identifier, advertising ID, photo, microphone input or list of installed apps. There is no profiling and no automated decision-making.
Where it is stored
Recordings and tracks are written into the app's private storage area on the phone. On Android that means other apps cannot read them, and neither can we — there is no mechanism in the app to send them anywhere on its own.
- Logbook sessions — one CSV per recording, one line per second.
- Track files — the line drawn on the chart.
- Settings — display preferences.
- Map tile cache — image tiles already downloaded, so the chart redraws without fetching them again. Capped at 200 MB.
Files are kept until you delete them. Uninstalling the app removes all of it, recordings included, with no copy left behind anywhere.
One thing to be aware of: Android's own backup. If you have Android's backup to your Google account switched on for this phone, the system may include True Helm's files and settings — including recordings — in that backup. That is a transfer between you and Google under your own account and your own settings; we neither receive it nor have access to it. You can exclude the app in your phone's backup settings.
What goes over the network
The app makes network requests for exactly one purpose: fetching map tiles while the chart on the TRACK tab is on screen. No other screen contacts anything.
A tile request necessarily tells the tile server your IP address and which square of the world you are looking at, which is an approximate location. The one server used is:
- Thunderforest (thunderforest.com) — the topographic base map.
Those requests reach their operators, who are independent of this project and handle server logs under their own terms. No identifier of you or your device is added to the request, and the request carries no track, no recording and no sensor data — only the tile coordinates, which every map application must send.
Turn off mobile data, switch the chart off with CHART OFF, or simply stay off the
TRACK tab, and the app makes no network requests at all. Every other function — the readouts, the timer, the compass, and the recording itself —
works fully offline.
Sharing a recording
In the sessions list you can share a recording. That hands the single selected file to Android's standard share sheet and, from there, to the app you choose — mail, a cloud drive, a messenger, a cable. It is a deliberate action per file, and the destination is yours.
What happens to the file afterwards is governed by whichever service you sent it to. Note that a logbook contains precise positions and times, which is exactly what makes it useful for analysis and also what makes it worth thinking about before uploading it somewhere public.
Permissions, and why
| Permission | Used for |
|---|---|
| Location (precise / approximate) | Speed, course, the track and the logbook. Also the local magnetic declination, so the compass can show true rather than magnetic north. |
| Foreground service, location type | Keeps the recorder running with the screen off and the phone in a pocket. Without it, a recording would have holes exactly where a race is interesting. |
| Notifications | Android requires a visible notification while that service runs. It is the only notification the app ever posts. |
| Internet / network state | Map tiles, and nothing else. |
The app deliberately does not request background location. The recorder is always started by you from the TRACK tab, in the foreground, which is enough for it to keep running — so the app never has permission to locate you when you did not start something.
Deleting your data
- A single recording: TRACK → SESSIONS → DELETE. You will be asked to confirm, because until a session has been shared it exists in one place only.
- Everything: uninstall the app, or clear its storage in Android's app settings. Both remove all recordings, tracks, settings and the tile cache.
There is nothing to request from us and nobody to ask: we hold no copy of anything, so there is no account to close and no deletion request to file.
This website
This site is static: plain HTML and CSS, with the two fonts served from this same site rather than from a font provider. It sets no cookies, runs no analytics, embeds no third-party scripts and loads nothing from another domain — which is why there is no cookie banner to click away.
These pages are hosted by Netlify, Inc., San Francisco, California, USA. Delivering a page means their servers record ordinary access data: your IP address, the time, the page you asked for and your browser's user agent. Every web server on the internet does this, and it is what makes delivery possible at all.
The legal basis is Art. 6 (1) (f) GDPR. The legitimate interest is running a website that can be reached and defended against attack. Netlify acts as a processor under Art. 28 GDPR and offers a data processing agreement with the EU standard contractual clauses covering the transfer to the United States.
What Netlify records, and how long it keeps it, is set out in their own privacy notice at netlify.com/privacy. Netlify also sells a web analytics product. It is switched off for this site, so nothing beyond those access logs is collected.
The contact form
The form on the contact page sends nothing itself. When you tap the button, your own mail app opens with the message already written, addressed to us. You decide whether to send it, and it then travels like any other e-mail, from your mail provider to ours. No copy is kept by this website or by its host.
- What we receive: what you wrote, the topic and, if you filled it in, your phone model and Android version. Like every e-mail, it also carries your e-mail address and name as your mail app sends them.
- Where it is kept: in our mailbox at Microsoft (Outlook.com).
- What it is used for: reading your message, fixing what you report and answering you. It is not added to any list and never used for marketing.
- How long: as long as the conversation needs it. Ask, and we delete it.
The legal basis is Art. 6 (1) (f) GDPR. The legitimate interest is answering the people who write to us and fixing what they report.
Questions
Anything unclear, or something in the app that does not match what is written here? Write to klaashoepcke@hotmail.de. A mismatch between this page and the app is treated as a bug in whichever of the two is wrong.
Changes
If the app starts doing something this page does not cover, this page changes first. The date at the top says when it last did.