User guide
How nautic.lu works
Everything here is free and works without an account — except two features, where that is not technically possible. This guide walks through what exists and how to use it.
First things first: it costs nothing
No base fee, no commission, no premium tier, no payment details. Listings are free, and there is no paid slot near the top. We do not sell addresses and we do not run adverts. If anyone anywhere on this site asks you for a payment, it is not nautic.lu — please tell us.
The four buttons that are always there
Three sit at the top beside the menu, one at the bottom right. They stay in the same place on every page — including on a phone, where they drop to a second row.
- Go out? — the day’s verdict. Wind, gusts, visibility, rain, thunderstorms and water level as one traffic light.
- Live trip — records a trip and keeps showing your kilometre and the next lock. Needs an account.
- CORVNI — the radio assistant. Type the situation, read off the finished radio call.
- SOS — bottom right, in red: the emergency page. One reach, no detour through the menu.
The SOS button dials nothing and transmits nothing. It only opens the page that tells you what to do. The call for help still goes through 112 and over the radio.
Finding a boat or a mooring
The marketplace splits into four sections. The search box on the home page takes you straight to the right one.
- Boats — everything for sale, from inflatables to displacement cruisers.
- Rentals — boats let by the day or the week.
- Moorings — annual berths and visitor berths in harbours and alongside pontoons.
- Wanted — those looking rather than offering post here.
In every section you can filter by place, price, length and year. Filters apply immediately, with nothing to submit. The search box at the top also covers the river data — type "Grevenmacher" and you will find both the listings there and the lock and the landing stage.
The heart on a listing saves it to your shortlist. That needs an account, because otherwise there would be nowhere to keep the list.
Posting your own
Through "Post for free" a listing takes two minutes to fill in. No account needed — an e-mail address is enough, and we send the edit link there. We read every listing once, so going live usually takes up to a day.
- Pick the type: sell a boat, rent out a boat, offer a mooring, or post a wanted ad.
- Enter a title, a price and a few details. The fields change with the type — for a mooring you give the harbour instead of engine power.
- Add photos. Pictures sell a boat better than any text; several angles beat one.
- Submit. We take a quick look so no advertising junk ends up here. Usually the listing is live within a day.
A listing has exactly one type. To sell and rent out the same boat, post two separate listings — both free.
Keep the edit link from the e-mail. It lets you change or delete the listing later, even without an account. Lost it? Write to us through the contact form.
If a listing looks odd, there is a report button under each one. That comes straight to us.
Getting in touch
There is a form under every listing. What you write there goes to the seller as an e-mail — your address appears as the sender, so they can reply directly.
- There is no inbox on nautic.lu. The reply lands in your ordinary mailbox and the conversation carries on between the two of you.
- We see your address, but we do not pass it on and we do not write to you. The seller sees it as soon as you send the form — otherwise they could not answer.
- Phone numbers are shown only if the seller has expressly allowed it.
No serious seller asks for a deposit before you have seen the boat. Anyone pressing for payment up front, or wanting to move the conversation elsewhere straight away, is usually not worth it. Report such listings — the link sits under each one.
Your boat profile — will it fit?
Enter your boat's dimensions once: length, beam, draught and air draught. The site then does the arithmetic at every bridge and every lock and tells you how much room is left.
- Every bridge page shows your clearance — first against the highest navigable water level, and where a gauge stands close enough, for today as well.
- Every lock page works against the chamber dimensions, main chamber and leisure-craft lock separately. For the small one your draught counts too.
- In the overview lists and on the map the verdict appears in short form — always with the figure beside it, never just a word.
The profile stays in your browser. Nothing is transmitted, stored or analysed. On another device you enter it again — and no account is needed.
It remains a calculation from our data, not a clearance. Where a bridge height comes from a single source, that is stated. The official information and your own eye are what count — and if you want a reserve, enter it as a safety margin; the default is zero, so nobody relies on a figure they did not set.
The Moselle cruising map
The second half of the site has nothing to do with the marketplace: a complete cruising guide to the Moselle, from the lock at Apach on the French border to the confluence with the Rhine at Koblenz. It all sits under "Moselle" in the menu.
- Cruising map — every recorded point on one map. Each point is clickable and opens its own page.
- Locks & weirs — the thirteen locks with kilometre mark, fall, chamber dimensions, leisure-craft lock, VHF channel and telephone number.
- Harbours, marinas & landings — where to find power, water, diesel, sanitary facilities, a slipway and a visitor berth.
- Bridges & air draught — kilometrage and clear heights — referred to the highest navigable water level, with a source for each bridge and, where a gauge stands close enough, a figure for today.
- Anchoring & mooring — what is allowed on the Moselle and what is not. In short: anchoring is prohibited, and there are designated berthing places.
- Water levels & floods — the Moselle gauges as a continuously updated table: reading, deviation from mean water, trend, plus Mark I, Mark II and HSW with the official sources.
- Rules, radio & licences — what applies in Luxembourg, Germany and France.
For every point, where its details come from is stated — for the position even with a source, and where there is none, that is said outright. Harbours entered by their own operator are marked as such. Never navigate by this site alone — the chart on board and the signage always take precedence.
What the harbour offers
Harbour and mooring pages list what is available on site: shore power, drinking water, fuel, pump-out, toilets and showers, slipway, crane, Wi-Fi, shops, food and visitor berths. The overview shows the same entries as a table, with a filter by facility.
Important: “not recorded” means we have not checked — not that there is none. That is why the filter does not hide such points but moves them to the end. When in doubt, a phone call is worth it.
The entries come from each point's own data. Some follow from a separate entry at the same place — a fuel station at the harbour counts for the harbour.
You know a harbour and spot a gap? Write to us — it is the quickest way to improve the site.
Water level alerts by email
You don't have to watch the water levels yourself — the Moselle can let you know. Enter your email address and pick one station, or all of them:
- When a gauge reaches Mark I you get an alert — navigation restrictions apply from here.
- At Mark II or HSW the next email follows: navigation is suspended.
- When the level drops, the all-clear arrives. Confirmed with one click (double opt-in), unsubscribed with one click in every email — free, like everything here.
What updates by itself
Part of the waterway data is fixed and will not change in years — chamber dimensions, kilometres, VHF channels. Another part changes by the hour. Those figures the site fetches itself, and it says when it last looked.
Water levels
The waterways administration’s gauges, refreshed every twenty minutes. On every lock, harbour and bridge page the nearest gauge sits in the side column: current reading, deviation from mean water, the trend over 24 hours, and a classification from low to navigation suspended. Worth knowing: readings from two gauges cannot be compared directly, because each has its own datum. That is why the deviation from mean water is printed alongside everywhere — that one is comparable.
Closures and faults
The official notices to skippers come in as Notices to Skippers and are sorted by Moselle kilometre. If a notice concerns a lock, it appears on that lock’s page. When it expires, it disappears by itself. We shorten nothing and reword nothing.
Bridge clearances
The clear heights of the Moselle bridges refer to the highest navigable water level — the level at which navigation is suspended. Which means: as long as you are allowed to move at all, at least the stated height is clear. Where a gauge publishing that value sits close enough to the bridge, we also work out a figure for today and show the arithmetic. Where it is too far away, we say so and do not calculate — at high water the surface falls away over the distance, and the estimate would err in the dangerous direction.
Where the figures come from
Below the data on each detail page there is a “Position” line giving the origin of the coordinate. Green means: from a named source. Otherwise it says the position was computed from the kilometrage and not verified on site. For clearances it also says whether two independent sources agree or only one was found.
Live data is without warranty too. A fetch can fail, a notice can slip past us. Only the official notices to skippers and the signs on the water are binding. If the timestamp next to a value looks older than it should, believe the timestamp.
Add your own harbour
The harbours on this site come from our own dataset. Anyone not in it long had no way in — not even the operator. That has changed: whoever runs a harbour, landing stage, slipway, fuel dock or pump-out station now enters it themselves. Free of charge, like everything here.
- The position is placed on the map, not typed: a pin where the facility lies, movable afterwards. We derive the Moselle kilometre from the position — nobody needs to know it.
- Plus the details visitors look for: berths and guest berths, maximum length and draught, water depth, power, water, diesel, crane, slipway, washrooms, wifi, season and when the harbour office is reachable. All optional — anything left blank does not appear.
- Up to six photos can go with it. A picture of the basin tells a visitor more than any list.
- Every entry is reviewed before publication, usually within a day. It then appears on the map and in the harbour list — marked as an operator record. That distinction is deliberate: it is the most obvious source for a harbour, but it is not an official one.
- Editing is possible at any time under “My account”, tab “My harbours”. Description, details and photos appear immediately. Only if the pin is moved on the map do we check again — someone steers their boat by that position.
Radio, channels and the CORVNI assistant
Calling a lock takes three things: a set, a certificate and the right words. The first two we cannot give you. With the words we can help.
- VHF radio & channels — the groundwork: which channels exist and what for, which channel applies at which lock, transmitter powers, ATIS and call signs, which certificate counts where — CORVNI in Luxembourg, UBI in Germany, mutually recognised. Plus an exam trainer using the questions from the official catalogue.
- Radio assistant — builds the radio call you need right now.
How the assistant works
- You say where you are — either through your device’s location or by picking the lock from a list. The assistant knows the channel that goes with it.
- You describe the situation briefly: reporting in, requesting a lock-through, agreeing a passing, reporting a fault.
- You get the finished call, line by line, in the language of the station you are calling — German on the German side, and accordingly on the Luxembourg and French ones. The procedure words stay untranslated, as the rules require.
Your boat name, call sign and boat type can be entered once; they stay in your browser and are uploaded nowhere. The assistant follows fixed rules and works without a network too, once the page has loaded. Only when no rule fits does a language model do the phrasing.
Transmitting without a valid certificate and an approved set is not allowed, and the assistant changes nothing about that. Nor does it replace the inland waterway radio handbook, which must be carried aboard vessels subject to the radio requirement — that is where the traffic centre channels are, and those are the ones that count in an emergency.
Go out today? — the daily assessment
This page answers one question: is it worth it today? It pulls together wind, gusts, visibility, rainfall, thunderstorm warnings and the water level, and shows a traffic light.
- Pick your spot on the Moselle and your type of boat — open boat, leisure craft up to about eight metres, or cabin boat. The thresholds shift with the type.
- You get the light, the reasoning behind it, the best window of the day and a table of the hours ahead.
- The thresholds are stated openly on the page. You can read at what wind speed a note appears and at what speed we advise against going.
A language model writes the text and answers follow-up questions — but it cannot overturn the light. The assessment follows fixed rules, so that what it rests on stays open to inspection.
This is guidance, not clearance. The assessment knows neither your boat nor your experience nor the people aboard. Weather in the Moselle valley varies a great deal from place to place. The decision rests with the skipper.
Underway — logging your trip
Once a trip is running, the page keeps showing your Moselle kilometre, the next lock upstream and downstream, the distance to it and the matching radio channel. This needs an account, because the log has to belong to your trip.
- Before the first time you are asked for consent explicitly, and you set how long trips are kept — from "only until the trip ends" to a year. Changeable at any time, and single trips can be deleted.
- The share link lets someone ashore follow where you are. Without that link, nobody sees anything.
- Logging only runs while the page is open and the trip is started. Nothing happens in the background.
This is not a safety system. It raises no alarm, nobody watches it, and without signal or battery it simply stops. In an emergency: call 112 and put out the distress call over VHF. If you sail alone, tell someone ashore where you are going and by when you will be back.
The planner heading south
The planner works in two directions: south to the Mediterranean (roughly 1,100 kilometres, some 145 locks) or north via the Rhine and the canals to Hamburg (roughly 1,000 kilometres, 24 locks). Enter your boat's length, beam, draught and air draught, and you will see whether it fits everywhere and how long the trip takes at your pace.
- Choose start and destination, set cruising speed and hours per day.
- You get the stages, the total duration and the places where your boat runs into a limit.
- With an account the plan can be saved; as a PDF it works without one.
The planner works out stages, not a lock-by-lock route. For the Moselle the real locks are listed with kilometre mark and radio channel on the river pages; for the French canals we point to the VNF charts.
The plan warns you about what lies on your route
Above the stage list, the “On your route” box shows the current situation on the Moselle section of your trip — automatically, from official sources:
- Closures and incidents from the notices to skippers (ELWIS), where they affect your kilometres.
- Gauges above Mark I or II as well as low water — with the current reading in centimetres.
- If nothing is going on, the box says so in green, in plain words. It is also in the PDF — with a timestamp, because a printout ages. Beyond the French border: check VNF’s avis à la batellerie.
Events in the calendar
Harbour festivals, regattas, joint outings, courses, trade fairs, wine and illumination festivals — entered by the people who sail here. Anyone can look; entering needs an account.
- The overview shows upcoming events grouped by month. A click opens the single event with place, time and description.
- To add one, go to “Add an event”. Sixteen types are offered, from the season opening to a harbour working party. Multi-day events get an end date, all-day ones need no time, and the country is stated — not every event is in Luxembourg.
- Photos and the programme belong with it: up to six attachments per event, photos or a PDF. The photos appear on the event page, the PDF below it for download.
- Every event is looked at once before it appears — the attachments too. What we go by is stated above the entry form: whether someone can go there, on a given day and at a given place. Until it is approved you will find the event under “My account”. As a rule that takes up to a day.
Forum
The part nobody can fill alone: questions about the river, trip reports, experience with locks, harbours and dealers. Anyone can read; writing needs a free account.
- Five sections: General, The Moselle, Technical, Trips, and Buying and selling. A meaningful title draws more answers than “Question”.
- Posts appear at once — a conversation that only shows up the next day is not one. In return, a post can be hidden afterwards if it insults or advertises.
- Pinned topics stay at the top of the list. Closed topics can still be read but no longer answered.
Two pages for the bad day and for practice
- Emergency — what to do on the Moselle when things go wrong: 112, MAYDAY and PAN PAN on inland radio, sound signals, a checklist for the lock and what belongs aboard. Worth reading calmly ashore, once.
- Knots — ten knots step by step: what each is for, how to tie it and which mistake turns dangerous.
The emergency page is also reachable at any time through the red SOS button at the bottom right, on every page and without going through the menu.
AI-assisted Where artificial intelligence does the work
In three places — and all three are built so it stays clear what the model does and what it does not.
- For the daily assessment it writes the text and answers follow-up questions. The traffic light follows fixed thresholds stated openly on the page — the model cannot overturn it. If the service goes down, the assessment and its reasoning stay unchanged.
- In the voyage planner it estimates the distance to a freely typed destination. The calculated stages from Schengen to the Mediterranean come from stored figures, not from the model.
- In the radio assistant it only does the phrasing when none of the stored rules fits your situation. Channel, procedure words and the structure of the call always come from the rules, never from the model.
Nowhere else. Listings are not written, rated or ranked by an AI. The river data comes from official sources and editorial work. What you type is not used for training.
What an account is for — and when you need none
Without an account you can: view everything, search and filter, use the whole cruising map, call up the daily assessment, run the planner, post listings and change them later through the edit link, use the radio assistant with its boat profile, and see all the live data.
You need an account for: the shortlist, trip tracking, saving route plans, adding events and forum posts, and adding and maintaining your own harbour. It is free and asks only for an email address and a password.
Under “My account” everything you have contributed sits together: listings, events, harbours and forum posts — each with its state, still under review or already visible. That is also where you add new ones. Events and harbours can be edited at any time; an approved event stays in the calendar meanwhile. If an event is not taking place, you take it out yourself.
On the phone: an icon like an app
A proper app for iPhone and Android is being written — in my spare time, and it will take a while yet. Until then, nautic.lu can be placed on the home screen in two steps. The site then has its own icon, starts without an address bar and looks like an app.
iPhone and iPad (Safari)
- Open nautic.lu in Safari. Other browsers do not offer this step.
- Tap the share icon at the bottom — the square with the arrow pointing up.
- Scroll down the list and choose "Add to Home Screen".
- Confirm the name and tap "Add". Done.
Android (Chrome)
- Open nautic.lu in Chrome.
- Tap the three dots at the top right.
- Choose "Install app", or "Add to Home screen" if the first entry is missing.
- Confirm. The icon then sits on the home screen; a long press on it leads straight to the cruising map, the moorings or posting a listing.
Getting by without a signal
On the Moselle the signal is poor in places. Whatever you have opened once stays on the device and opens again without a connection.
- Pages you have visited — locks, bridges, harbours, radio, emergency.
- The cruising chart including its base map, if you downloaded it beforehand: the button sits below the map, with the size shown. Best done on Wi-Fi.
- Points, kilometrage, chamber dimensions and air draughts — everything that does not change by the hour.
When a page comes from storage, a yellow band at the top shows its age. Water levels, closures and lock notices change by the hour — what you see offline may be out of date. A distress call, incidentally, needs no internet: VHF channel 10 and 112 work without a data connection.
The downloaded map can be deleted from the device at any time — the button is in the same place.
This is no substitute for a real app — it is the same site, just without the browser frame. It does not work without a network, and there are no notifications. When the native apps are ready, it will say so here.
Languages
The site comes in German, French and English. The switcher sits in the header, right next to the menu button on narrow screens. The addresses are translated too — the same page has a different name in each language, and switching always lands you on the same page, not on the home page.
Dark display
At the very bottom of every page there is a small switch. It turns the site to dark colours — easier on the eyes in the evening on board, where a white screen dazzles and night vision takes a while to return. The cruising chart goes dark too.
Before that, the site follows your device: if your phone switches to dark in the evening, so does the site. Your own choice applies only once you use the switch — and only while it differs from the device setting. Set it back to what the device does anyway, and the site follows it automatically again.
What sits where in the menu
At the top, the four areas: boats, rentals, moorings and the Moselle. Behind “Moselle” the order follows the question you have:
- Underway — what you look up on the water: map, locks, bridges, harbours, anchoring, water levels.
- Before you go — what you sort out beforehand: whether today is a good day, your boat profile, trip planning.
- Skills & rules — what you need to know: cruising guide, radio and channels, the CORVNI assistant, knots.
If something does not work
Write to us through the contact form. A bug report is as welcome as a correction to the river data — if a lock number is out of date or a harbour has closed, say so. This site lives on people who actually go out there reading along.