Privacy Policy for Marine Metrics
This Privacy Policy explains how Marine Metrics (“the app”, “we”, “I”) collects, uses, and protects your information when you use the Marine Metrics iOS application.
In short: there is no account, and there is nothing to sign in to. Your saved spots and settings stay on your device. If you allow location access, your position is rounded to roughly a kilometre before it is used to request tide data. There is no analytics, no crash reporting, no advertising, and no tracking of any kind.
Information We Collect
Information You Provide
- Saved spots — the names and coordinates of places you bookmark. Stored on your device only.
- Search terms — text you type into the spot search. Sent to Apple’s MapKit to return results, and not retained by us.
- Preferences — your unit choices, default launch location, and chosen app icon. Stored on your device only.
Information Collected Automatically
- Approximate location — only if you grant location permission. See “Location” below for exactly what is sent and how precise it is.
- Purchase information — if you subscribe, your subscription status, the product purchased, and renewal or expiry dates are processed to unlock and maintain paid features. See “Subscriptions and Purchases”.
- Device verification — an anonymous cryptographic key identifier used to confirm that requests come from a genuine copy of the app. See “Device Verification”.
Information We Do Not Collect
- No name, email address, phone number, or account of any kind
- No analytics or usage tracking
- No crash reporting
- No advertising identifiers, and no advertising or marketing SDKs
- No contacts, photos, calendars, health data, or microphone access
Marine Metrics does not track you across apps or websites, and shows no App Tracking Transparency prompt because it has nothing to ask for.
How We Use Your Information
- To work out which tide station is nearest to you, and to show spots near you
- To request tide predictions, wind, and sea temperature for the place you are looking at
- To remember the spots you save and the settings you choose
- To keep your Home Screen widgets showing the spot you last opened
- To unlock paid features for subscribers
We do not sell, rent, or share your personal data with third parties for advertising or marketing purposes.
Location
Location access is optional and is requested only while you are using the app. Marine Metrics works without it — it falls back to a built-in list of well-known coastal spots, and you can set a default launch location in Settings.
If you do grant it, three things are true about how your position is handled:
- It is rounded before it is sent. Coordinates are snapped to a grid of about 1.1 km before any tide request leaves your device. This is deliberate — tide stations are kilometres apart, so finer precision would change nothing about the answer.
- Wind and sea temperature are not requested at your position. They are requested at the coordinate of the public tide station your location resolved to, which is a fixed, published location rather than yours.
- It is never stored on a server. Your position is used to build a request and then discarded. No location history is kept, by us or in the app.
Searching for a spot sends your typed query, and the region you are viewing, to Apple’s MapKit. That is governed by Apple’s Privacy Policy.
Data Stored on Your Device
Your saved spots, unit preferences, launch location, chosen app icon, and cached tide forecasts are stored on your device. They are not uploaded to us and are not synced to iCloud.
A small amount of that data — the spot you last opened, your height unit, and whether you are subscribed — is shared between the app and its Home Screen widgets using an Apple App Group. This is a private area of your own device; it is not transmitted anywhere.
You can clear cached forecasts at any time in Settings. Deleting the app removes all of it.
The Tide Service
Tide predictions are requested from a service operated by us and hosted on Supabase. Each request contains the rounded coordinate described above, the range of dates you are viewing, and a device verification assertion. It contains no name, no account, and no advertising identifier.
Answers are cached by that service and shared between everyone who asks about the same area, so the same request from a different person returns the same stored answer. The cache is keyed by place and date, not by person or device.
Tide heights and times shown in the app are predictions produced from a harmonic model, not live sensor readings.
Other Services
Marine Metrics requests data from these third parties. In each case the coordinate sent is the public tide station’s, not your device’s position:
- Open-Meteo — wind forecasts. Open-Meteo terms and privacy
- NOAA CoastWatch — satellite sea-surface temperature, from the US National Oceanic and Atmospheric Administration. NOAA privacy policy
- Apple MapKit — place search and geocoding. Apple’s Privacy Policy
Subscriptions and Purchases
Marine Metrics offers an optional subscription. Payments are processed by Apple through the App Store; we never receive or store your payment card or financial information.
To manage subscription entitlements — verifying which features you have access to — we use RevenueCat, a third-party subscription management service. When you make or restore a purchase, RevenueCat processes:
- The product identifier and transaction information for your purchase
- Your subscription status, including trial, renewal, and expiry dates
- An app-generated anonymous identifier and basic device and country information
That identifier is anonymous: it is generated by the app, is not linked to a name or an email address, and does not identify you to us personally. RevenueCat acts as a data processor on our behalf, and the data it handles is governed by RevenueCat’s Privacy Policy. Purchases are also subject to Apple’s Privacy Policy.
Subscriptions support Family Sharing. If a family member shares a subscription with you, Apple tells the app that you are entitled to paid features; it does not tell us who bought it or share their personal information with us.
Device Verification
Marine Metrics uses Apple’s App Attest to confirm that requests to our tide service come from a genuine, unmodified copy of the app rather than from someone who has found the address of the service. This keeps the cost of the data under control.
A cryptographic key is created in your device’s Secure Enclave, and its identifier is stored by our service alongside a counter. The key cannot be used to identify you, is specific to this app on this device, and is destroyed when you delete the app. No personal information is involved.
Notifications
Marine Metrics does not send you push notifications.
Data Retention
Data stored on your device remains until you delete it or remove the app. Cached forecasts can be cleared in Settings at any time.
Requests to our tide service are not logged against you, and cached responses are held by place and date rather than by person. Device verification records are kept for as long as the app remains installed and verifying.
Subscription records held by Apple and RevenueCat are retained according to their respective policies and applicable financial record-keeping requirements.
Your Rights
If you are in the UK or the European Economic Area, you have rights of access, correction, deletion, and portability over personal data relating to you.
In practice, almost everything Marine Metrics holds is on your own device and under your control: deleting the app deletes it, and we hold no copy. For data held by RevenueCat in connection with a subscription, or if you have any other request, contact us using the details below and we will respond.
Children’s Privacy
Marine Metrics is not directed at children under 13. We do not knowingly collect personal information from children under 13.
Safety
Tide predictions, wind, and sea temperature in Marine Metrics are provided for general information. They are not navigational data and must not be relied upon for navigation or for decisions affecting safety of life at sea.
Changes to This Policy
We may update this Privacy Policy from time to time. We will notify you of material changes by updating the “Last updated” date at the top of this page. Continued use of the app after changes constitutes acceptance of the updated policy.
Contact
If you have any questions or concerns about this Privacy Policy, please contact:
Liam Hennessy
Email: c25krunnerfeedback@gmail.com