Privacy policy
Last updated 19. oktober 2026
Klamp is an app where boat owners share harbour berths. This policy explains, in plain language, what information we handle, why, and what you can do about it.
In short: We collect as little as possible. We store your position only if you switch Ahoy sharing on yourself — and then only the latest one, never a history. Your name is shared only if you say so. We use no cookies and do not track you across the web. Your data lives in the EU; the few services outside it are named further down.
Who is responsible
Vizion Holding ApS is the data controller. Write to ahoy@klamp.app about anything concerning your information.
What we handle — and why
| Information | Why | Basis |
|---|---|---|
| Email address | Your account, and news about your berth | Contract |
| Name (optional) | Shown only if you share it | Consent |
| Phone number (optional) | So a guest can reach you, if you want | Consent |
| Your berth: harbour, number, coordinate, size | So guests can find it | Contract |
| Your boat: name and dimensions | Warning when a berth is too small | Contract |
| Availability periods | The heart of Klamp | Contract |
| Photos of the berth | So guests can see where to go | Contract |
| Device token for notifications | Push messages | Consent |
| Your position, while you share it in Ahoy | So other sailors can see you on the water | Consent |
| Anchor watch: radius, times and the distance at an alarm — never the anchorage itself | So we can pass the alarm on to your other devices | Contract |
| Feedback: your text and the app's version number | So we can fix faults and prioritise wishes | Consent |
| Klamper, greetings, notes and reports you write yourself | The community — and being able to step in when someone abuses it | Contract |
| The berth owner's note when he ends a stay you did not release yourself | So you can see why your stay was ended. Only you and the berth owner can read it, and it is deleted after 90 days | Contract |
| Reservations and contact shares | So guest and owner can arrange a stay | Contract and consent |
| Messages between you and your counterpart in an arrangement | So you can sort out the practicalities in the app — without having to share a number or a name | Contract |
| Two-factor sign-in, if you turn it on (encrypted) | An extra lock on your account | Consent |
| Scans of your sign: when, never who | So you can see whether the sign is being used | Contract |
| Your app settings: units, theme, language choice, planning speed and your depth margin | So they are the same on all your devices | Contract |
Your position
Klamp uses your position to show nearby harbours, to confirm you are at the berth when you take it, for navigation — and for Ahoy, if you switch it on yourself. Only the last one leaves a position with us, and that is set out below.
What is never stored
When you take a berth, the app sends your coordinate to the server, which only calculates the distance to the berth and then discards it. We keep the result — that you were close enough — not where you were.
The map and the navigation run on the phone. Your track is never sent to us — it sits in your own logbook, and how it can follow you to your other devices is set out in the section just below. If you turn on the wind layer, or open the weather for a harbour, the phone asks Apple's weather service directly — and that request goes around us. What is sent is the place you are looking at: the centre of the map or the harbour's coordinate, never where you are yourself. Severe weather warnings from the weather authorities arrive the same way; if you tap through to the authority's own page, dmi.dk for instance, you open their website like any other — they see your IP address, and we send them nothing about you.
Your logbook and your man overboard log — in YOUR iCloud, never with us
The logbook and the man overboard log stay on the phone, and they follow you to your other devices through your own iCloud. They never pass through Klamp's servers. We have no access to them: they sit in the private part of your iCloud, which only your own Apple account can open, and the contents themselves are encrypted with a key from your iCloud Keychain. We can neither read them nor hand them over — not even if someone asked us to. That is the whole reason we chose this route over our own server.
You can turn it off. Settings → Across devices. Then the logbook and the log stay only on the phone in your hand. If you are not signed in to iCloud at all, nothing happens — the app works as before.
Deleting applies to every device of yours. Delete a passage or an event and it also disappears from your iCloud and from your other phones. Delete your Klamp account and they go with it.
Your saved routes and your search history do not follow along — they stay on the individual phone.
Two different keys, and that is deliberate. Your settings — units, theme, language choice and your boat's draught — follow your Klamp account, sit with us, and are in place the moment you sign in on a new phone. The logbook and the man overboard log follow your Apple ID and sit only in your own iCloud. The switch above therefore covers only the last two: turn it off and the logbook and the log stay here on the phone — your settings still follow the account.
Ahoy — the one feature where we do get your position
Ahoy lets you see other Klamp sailors on the water, and lets them see you. Sharing is off from the start and can only be switched on by you actively saying yes. If you do not, we never see your position at all.
If you do switch it on, we store one position: the latest. A new one overwrites the previous, so there is nowhere to look up where you were on Tuesday — not for us either. Others are never served a position more than 10 minutes old, and the row itself is deleted in the daily clean-up once it is over half an hour old.
Strangers do not see where you are. They see a dot rounded to a fixed grid of about 100 × 60 metres — no name, no boat name, and no user id. Only a pseudonym that differs for every person looking, and is new every day. No course, no speed. Your exact position is seen only by the sailors you have approved yourself.
One tap switches it off. The red button turns sharing off and deletes the position at our end in the same second — it is not hidden, it is deleted. It is free, it can never be blocked, and it works whatever subscription you have. Delete your account and the position goes with it in the same moment.
The anchor watch
The anchor watch keeps an eye on whether the boat is dragging while you sleep. The server never learns where you are anchored. The anchor point stays on the phone. All we know is the radius you set, when the watch started, and — if the alarm goes off — how many metres were involved, so we can pass the message on to your other devices. A distance without a zero point says nothing about where.
What we guard most carefully
"The berth is free until 3 August" also means "the owner is away until 3 August". That is sensitive information, and we treat it that way:
- Public surfaces — the map, QR scanning without an account — never show who owns a berth.
- Your name is shared only within a specific stay, and only if both you and the other person actively agreed. The default is off.
- We do not know your home address. We only know the harbour.
Photos and the help chat
Photos you upload are checked automatically by an AI service (Anthropic) before they become visible, so other sailors only see harbours, docks and boats. Rejected photos are never shown to anyone but you.
The help chat in the app has no access to the database. It can only read Klamp's guide and knows nothing about you, your berth or your boat. Your question is sent to Anthropic to be answered, but neither the question nor the answer is stored with us — the chat does not even require a login, so we do not know who asked.
Tips about harbours
You can send a tip about a harbour from the app or from the harbour's page on klamp.app. The tip is sent to an AI service (Anthropic), which filters out spam and rewrites it as neutral text in Danish, Swedish and English. Nothing is shown before we have read and approved it, and it is always shown without your name.
On the website you may add your name and e-mail address if you wish. We only keep them if you tick «Klamp may contact me about my tip», and only so we can reply to you about that tip. Your name and e-mail are never sent to Anthropic. They are deleted together with the tip's original text: 90 days after the tip is approved, 90 days after it was sent if it is rejected, and after 180 days at the latest.
If you tick «Yes please to Klamp's newsletter», we keep your e-mail address, your name, your language and when you said yes, so we can document your consent. We use the address for the newsletter and nothing else, and we never share it. You can unsubscribe at any time by writing to ahoy@klamp.app.
To stop robots, we compute a short number from your IP address using the same daily key as our visitor statistics. The number is deleted within the same day, and the IP address itself is never stored.
Messages in the app
If you have an arrangement about a berth — a reservation or a stay — you and your counterpart can write to each other in the app. The thread shows only your roles and the boat's name; your real names appear only if you have chosen to share contact details with each other.
The messages are yours, and we treat them that way: they are shown only to the two of you, they are never put into a push notification (the lock screen gets a neutral line saying there IS a message), and they never appear in our logs. Messages between you and your counterpart are kept while the arrangement lasts and deleted no later than 90 days after the stay or reservation ended — or immediately, if either of you deletes your account. You can also clear the conversation from your own view at any time; your counterpart's copy remains, just as yours remains if they clear theirs. You can report a message and block your counterpart — a block closes the thread immediately, both ways.
Website statistics
No cookies, no fingerprint, no IP stored. We can see that a browser visited us twice today; tomorrow that link is mathematically gone — for us too.
How it works: when you open a page, the server derives a short number from your IP address and your browser's name, mixed with a random number that exists only in the server's memory and is replaced every day. Your IP address and your browser's name are thrown away immediately — only the result is kept. When the day is over the random number is discarded, and then no one can work backwards. Not even us.
We keep: which page, when, that short-lived number, which website you came from if any (the host only, e.g. google.com — never the full address and never your search terms), the campaign tags in the address if you arrived from a campaign link, which country, whether you are on a phone, a tablet or a computer, and which kind of operating system. We never keep your IP address, never your browser's full name and never a city or a position — and if you scan a QR code, every berth is collapsed under a single path, so the measurement cannot see which sign you were standing at.
The individual visits are deleted after 60 days. What remains is plain numbers — "the front page was opened 412 times on 3 August".
Scans of the sign are counted separately. When someone scans the QR code on a berth, we store that this berth was scanned, and when — so the owner can see whether the sign is being used. No IP address, no browser and no user id goes with it, so the number tells you about the berth, never about who was standing in front of it. The count disappears together with the berth.
You meet no cookie banner, because we neither store nor read anything on your device. We use no one else's analytics tools, and the numbers never leave our own servers.
What we have given up: we cannot tell whether you come back tomorrow, and we cannot follow you from phone to computer. That would need a cookie or a fingerprint — and the price is worth paying.
Who we share with
| Recipient | Purpose | Location |
|---|---|---|
| Sevalla | Hosting and database | EU (Frankfurt) |
| Apple | Push on iPhone and iPad, sign-in, weather data, payment and subscriptions (Klamp+ via the App Store) | EU/US |
| Mailgun (Sinch) | Emails from Klamp | EU |
| Anthropic | Photo checking, the help chat and harbour tips (the tip text only) | US |
| Push on Android (Firebase Cloud Messaging) and Sign in with Google (only if you use it) | EU/US | |
| Cloudflare | The edge in front of klamp.app: TLS and protection against attacks. All traffic passes through them, including your IP address | EU (Frankfurt)/US |
Transfers outside the EU rely on the European Commission's Standard Contractual Clauses. We never sell your information and do not use it for advertising.
Push notifications travel through the phone's own platform. A notification can only reach a phone in a pocket through whoever made the phone's operating system: on iPhone and iPad we send it through Apple, on Android through Google's Firebase Cloud Messaging. The platform receives an address for this app on your phone (a token — on Android it is only fetched once you are signed in and notifications are on), the notification's title and text, and an internal number the app uses to open the right place. To issue the address, Firebase registers the app's installation on the phone with Google. We write the text so it can sit on a lock screen: boat name, berth name and harbour, for example — never your name, your email address, your position or words from the messages between sailors. If a notification cannot be delivered, Google keeps it for one day at most. Of Firebase we use only the messaging part: no analytics, no crash reports and no advertising ID. If you sign out, we delete the address on our side and the app asks Google to forget it; if you turn notifications off in the phone's settings, the app removes the address on our side the next time it is opened.
The chart layers are fetched by the phone itself. The depth colours on the chart come from EMODnet and the seamarks from OpenSeaMap, and your phone fetches those tiles directly from them. They therefore see your IP address and which area you are looking at — as when you open any website at all. They get neither your name, your account nor your berth, and we send them nothing about you. Harbour data from OpenStreetMap and the vessels with AIS transmitters (Data via AISHub), on the other hand, we pull in to our own server; there the traffic only goes one way. AISHub receives one request a minute for a fixed sea area — always the same one, whether or not anyone is using the app. They therefore never learn who is looking, where you are, or whether you have opened the chart at all.
How long
We keep your information for as long as you have an account. Delete the account and it is deleted. Stays you have had are kept in anonymised form with no connection to you, so harbour statistics remain accurate.
Some things have a limit of their own: your position in Ahoy is shown for at most 10 minutes and deleted in the daily clean-up · feedback you send from Profile is kept for two years · the raw visit figures for the website for 60 days · a report for at most a year, and its free text is cleared after 90 days once the case is settled or abandoned.
Your rights
You have the right of access, rectification, erasure, restriction, objection and data portability. You can delete your account directly in the app under Profile — everything personal is removed.
If you would like a copy of your information, write to ahoy@klamp.app. We do not yet have a button for it in the app, so we assemble it by hand — but the right is yours, and we answer within a month.
Note: the QR code on your sign cannot be recreated. If you delete your account, a printed sign stops working.
If you are unhappy with how we handle your data, you may complain to your national data protection authority. In Denmark that is Datatilsynet, datatilsynet.dk.
Children
Klamp is not directed at children under 16, and we do not knowingly collect information about them.
Changes
If we change anything significant, we will say so in the app before it takes effect.