Frequently asked questions

The device at the top of the list. The Hub puts a newly detected device at the top of the list; you change the order under Settings › Networks › Data Sources by dragging the handle symbol.

The next source then takes over automatically, for GPS after 5 seconds without a value. When the better source sends again, it applies again.

No. The Hub converts the magnetic heading to true itself. It always treats heading from the NMEA 2000 bus as magnetic, also from true sources such as satellite compasses.

Yes, as soon as wind sensor and GPS are there, even if your instruments do not calculate it themselves. For the direction at anchor you also need a compass.

Grey means the source has sent no data for 30 minutes.

Yes, press and hold the name and confirm "Delete". If it sends again later, it appears at the top of the list; you can only switch off the Hub's built-in sensors.

Connect your tablet or phone to the Hub's Wi-Fi and create a TCP connection in the navigation app: address 10.10.10.1, port 2021. If the Hub is on a different Wi-Fi, use the address the router has assigned to the Hub.

Position, course and speed over ground, heading, speed through water, depth, water temperature, apparent wind and all AIS targets. It does not matter whether the values come from the NMEA 2000 bus, from an NMEA 0183 device or from the Hub's sensors.

Yes. The Hub supplies at least position, course and speed from its built-in GPS, so even a tablet without its own GPS becomes a navigation device.

Up to 5 at the same time. If a sixth device joins, another one has to disconnect. You need no internet or subscription for this.

Yes. Open Settings › Networks › "NMEA 0183 Source", switch "Use the NMEA 0183 cable source" off, enter the IP address and port of your multiplexer and tap "Connect".

Under Settings › Networks, "NMEA 0183 Source" is followed by either "Disabled" or the IP address of your source. On the "NMEA Settings" page you also see the port.

Open Menu › Hub Health › NMEA 0183 and tap "Connect to NMEA 0183 multiplexer". The app shows the sentences your navigation app also receives, and you can copy them to the clipboard.

At sea, radar strongly interferes with the 5 GHz band, and the connection keeps dropping. That is why the Hub's own Wi-Fi deliberately transmits only on 2.4 GHz and picks the least disturbed channel there by itself. This is plenty for navigation apps and the Smartboatia app.

Open Settings › Calibration › Motion sensors. You do step 1 with the boat lying still, for example in the harbour; in step 2 you sail one slow full circle to starboard and one to port and then tap "Stop & calibrate".

After step 1 tap "Swap Prt/Stb". After step 2 the Hub determines the side itself, and the button disappears.

Yes. Tap "Re-calibrate", confirm and do step 1 and step 2 again. Your recorded data is kept.

Yes. The Hub has its own GPS, barometer, motion sensor and voltage measurement and records position, air pressure, attitude and supply voltage even on boats without instruments. At anchor or in the harbour you can switch off the Plotter and instruments, and the Hub still keeps the anchor watch and boat monitoring active.

It shows how strongly your boat is moving right now and has no unit. The value is specific to each boat; after a few trips you know which values mean calm, comfortable or rough on your boat.

You set that in the data source order. By default your instruments take priority over the Hub's sensors.

The motion sensor of your Hub is not yet fully calibrated to its mounting position, so until then the heel is only an estimate. Tap the notice to go straight to the calibration, and do step 1 and step 2.

No data is arriving for this reading right now, for example because the sensor has failed or is restarting. In Hub Health you can see from the status of each service which sensor is affected.

No. You connect the Hub directly to your boat's NMEA 2000 backbone. It registers on the network after a few seconds, no setting in the app is needed, and you do not need a subscription.

Position, speed, course, wind, depth, water temperature, air pressure, rudder angle, batteries, tanks, AIS and the state of your autopilot. The values flow automatically into the Plotter, logbook, alarms and history views.

Raymarine, B&G, Simrad and Lowrance as well as devices that use the NMEA 2000 standard for this. The Hub detects whether your autopilot is switched on and in which mode it steers, and with many devices also the target course.

Some devices do not register on the network with manufacturer and address, and the Hub only uses their values for the first 30 seconds. Under Settings › Networks › Data Sources › "NMEA 2000 Sources" switch on "Allow unknown NMEA 2000 sources".

By default your instruments on board take priority over the Hub's GPS and barometer. Under Settings › Networks › Data Sources you set the order for each data type yourself.

Send us a raw data export: Menu › Hub Health › NMEA 2000 › "Start Export", then "Share Log File" to support@smartboatia.com. We evaluate every export and gradually build new device data into the product.

Yes. The Hub records all boat data itself as soon as it has power, without internet, without an account and without a subscription. Offline is the normal case.

On board the Hub keeps the data for 400 days. If you connect the Hub to the cloud, the last 3 months stay stored there without a subscription, and with the Standard subscription the entire history permanently.

No, that is up to you. Without a Smartboatia ID the Hub records fully but uploads nothing to the cloud.

Under Settings › System › "Cloud Sync" you see the point up to which the complete sensor data is synchronised. A tick means everything is transferred; the cloud turns orange if the status is older than 24 hours.

Without a subscription the full resolution arrives with a delay of up to 6 hours, plus a coarse live track once per minute right away. With the Standard subscription the full resolution is there after about a minute.

No, everything stored is kept. Only the last seconds before the failure can be lost, and the transfer to the cloud then resumes where it stopped.

Yes. If the Hub is on the NMEA 2000 bus, it makes the values of its own sensors available to your other devices, even if no sensor of its own is installed on board for them. The Smartboatia app shows you the air pressure trend and the storm warning.

Under Settings › Networks › "Hub Data to NMEA 2000" you flip a switch for each value. Everything is on by default, and the Hub keeps your choice across restarts and updates.

No. The Hub sends independently of the app and without internet; your devices get the values even without a connected phone.

On your chartplotter select the Hub source if it does not take it automatically, and check whether your bus has power and terminators. After a Hub restart you may have to select the source on the chartplotter again.

As a backup: an additional position source in case your onboard GPS fails.

No. AIS works entirely on board, without internet, without an account and without a subscription. You only need an AIS receiver or transponder on the NMEA 2000 network or on an NMEA 0183 Wi-Fi multiplexer that the Hub uses.

No. CPA and TCPA are a display only, with no sound, notice or push. There is no collision alarm and no guard zone.

Yes. The Hub passes every AIS target on over Wi-Fi to navigation apps such as Garmin Boating (formerly Navionics), OpenCPN or Aqua Map, whether it receives them over NMEA 2000 or NMEA 0183. This way you see AIS from an NMEA 2000 transponder in your navigation app, without an additional gateway.

For CPA and TCPA the app needs your current position, speed and course over ground, and the other vessel has to send speed and course. If one of these values is missing, CPA and TCPA stay empty.

If a vessel does not report for 2 minutes, its symbol fades. After 10 minutes without a report it disappears from the app.

No, AIS is only available on board. The Hub does not store AIS and does not send it to the cloud.

Your boat remotely on one screen: when it last sent data, the last supply voltage, trip duration, distance and average speed, your logbook and a chart with the track. On a tablet a wind rose and base wind are added.

Your last trip according to the logbook, from casting off to the next berthing, mooring or anchoring, or up to now if the trip is still running. You choose a different period at the top right in the time range selector.

Without a subscription "Last seen" and supply voltage arrive every minute as long as the Hub has internet over Wi-Fi, track and charts with a delay of up to 6 hours. With the Standard subscription also every 5 seconds, track and charts after about a minute.

A Smartboatia ID, a boat in the cloud (your own or a friend's) and internet on your phone or tablet. Your Hub is connected to the cloud for this.

On board the app opens the Plotter, which takes over the role of the Dashboard there. If your Hub is reachable on the same Wi-Fi, the app connects to it directly.

Open Menu › Environment and tap the Barograph tile. The air pressure display on the map also opens the barograph.

Tap the time range selector at the top right and choose "Show last" (on board only), "Pick from calendar" or "Pick from ship's log". The period also applies to the other screens with a time range selector, for example the map with your track.

On board it matches what your boat is doing right now: when under way everything since casting off, at the berth everything since berthing. Remotely the app shows your last trip according to the logbook.

On board 400 days, straight from the Hub and without internet. Remotely the last 3 months without a subscription, the entire history with the Standard subscription.

There are no values for this data type in the selected period. For some data types you need the matching devices, for example an echo sounder for depth; air pressure, sea state and supply voltage are measured by the Hub itself.

Yes, if you connect the Hub to the cloud. You and your Boat Buddies then see the same views with your boat's history.

Without a subscription the app shows a base map with land, coast and water, but without aids to navigation, depth figures or fairways. With the Standard subscription you also get the official nautical charts of the BSH for Germany and of NOAA for the USA; more areas are in preparation.

The map is not an approved means of navigation. Map and nautical chart data do not replace official nautical charts and notices to mariners.

Yes, with previously downloaded offline maps. Everything from the Hub, that is boat, track, berths, manoeuvres, AIS and anchor watch, works on board without internet.

Tap the spot where your anchor lies, at most 100 m from your boat, and then tap "Set Anchor Watch" in the sheet.

Tap the layers button at the top right of the map and switch the layers you want on or off in the "Map overlays" dialog. Your choice applies to all maps in the app.

Yes, the boats you follow appear live on every map, including on your Plotter during your own trip. For this you need internet on your phone or tablet.

Open Menu › Settings › Offline Maps, tap "Select region", place the rectangle over your cruising area and tap "Download". After that every map in the app shows this area even without internet.

One download covers up to 150,000 km², which is roughly an area of 200 by 200 nautical miles. For a larger cruising area you simply download several areas next to each other.

Not for the base map, and no Hub either. With the Standard subscription every download additionally contains the nautical charts available for your area, currently the official nautical charts of the BSH for Germany and of NOAA for the USA.

No. Downloaded areas stay on your device with no expiry date until you delete them, also across restarts and signing out.

In the "Maps" list tap the area and "Delete" at the bottom, or press and hold it and confirm.

A running download only lives as long as the app is running. If the list says "Download interrupted", remove the area and start the download again.

Tap the short name of a tile, for example "SOG", choose the group and then the instrument. The tile changes immediately, and the app saves your choice; 33 instruments are available, plus the engine instruments as soon as your engine sends data.

No. The Plotter runs on board as soon as your app is connected to the Hub. With the Standard subscription the map in the Plotter also shows official nautical charts, currently of the BSH for Germany and of NOAA for the USA.

No value is arriving from a sensor or device for it. For the values you need the matching devices, for example an echo sounder for depth or a wind sensor for wind; air pressure, heel, sea state and supply voltage are measured by the Hub itself.

No. The instruments have no warning thresholds, including no shallow water warning on depth.

If you choose the boat type "Motorboat" under Boat configuration, the app hides the views for sailing boats: trim impact, trim advice, polars and the five performance instruments. The round instrument stays, without the coloured sailing sectors and without heel. The wind instruments in the bar stay, and if your engine sends data, you get engine instruments and the engine cockpit.

Yes, from version 1.48.0, as soon as your engine sends its data into the NMEA 2000 network and the Hub is on the same network. You choose the values as instruments in the Boat group under "Engine", and a dedicated engine cockpit page shows RPM, gear and the most important engine values at a glance.

The course is the planned direction of the current leg of your route, the bearing is the direction from your current position to the waypoint. If you have drifted off the course line, the two values differ.

No. The engine instruments have no warning thresholds. If your engine itself reports a warning, it appears as text in the engine status, without sound and without push notification.

No, the Plotter is only available on board. Remotely you see your boat in the Dashboard and in boat monitoring.

Tap the ruler symbol at the top right of the map and then tap the points on the map. You immediately see distance and true bearing of each leg and the total distance.

Switch on "Dock to boat". The route then starts at your boat, and the app shows the expected remaining time per leg and in total as well as the arrival time, calculated from the distance along the route and your current speed over ground.

If you are slower than 0.5 kn or your speed is older than 45 seconds, the app shows no time. Without a live position "Dock to boat" is greyed out.

Up to 50 points. If the ruler is docked to the boat, your boat counts as a point, so there are 49 waypoints.

Yes. The docked route feeds the waypoint instruments in the Plotter, such as distance, duration and arrival for the next and the last waypoint.

Yes. Your route stays saved on your device, separately for each boat, even after an app restart. The ruler calculates without internet, without an account and without a subscription.

Raymarine, B&G, Simrad, Lowrance and autopilots that transmit the NMEA 2000 standard. The autopilot has to be on the same NMEA 2000 network as the Hub.

No. If your autopilot is on the Hub's NMEA 2000 network, the Hub writes the entries itself, without internet and without a subscription.

From 10 degrees. The Hub compares with the last logged course, so five times 2 degrees to starboard also produce an entry.

You can delete it on board, connected to the Hub, by swiping it to the left in the logbook. You add a note with the pencil; you cannot change the time or type of an autopilot entry.

There is no push notification. On board you can switch on the "Autopilot" category under Settings › System › "Detected logbook entries", and then the app asks for every autopilot entry.

No. The Hub uses AI to detect whether your engine is running, without an engine sensor and without a connection to the engine electronics, and writes "Engine on" and "Engine off" into the logbook. This runs on board, without internet and without a subscription.

On board, enter yourself on a few trips when you start and stop the engine, via "+" › "Quick Entry" › "Engine on" or "Engine off". Enter the changes as completely as possible; with every engine entry of your own the model on your Hub gets to know your boat better.

When your boat is berthed and at least 3 hours of new trip have accumulated since the last training, with at least two sections in which the engine was running and off. The Hub checks this every 8 hours.

Under Menu › "Hub Health" › "Engine detector". Among other things it shows whether the baseline model is still working, the detection accuracy and when the last and the next training are.

Swipe it to the left in the logbook and delete it. For the model to learn from it, you also set the correct entry yourself.

Connect the app to your boat in the cloud, choose a trip from the logbook or up to 14 days from the calendar in the time range selector and tap "GPX Export". After a few minutes you get an email with the download link.

Yes, the GPX export comes with the Standard subscription for your boat. Without a subscription you see your tracks on the chart in the app and can create the PDF logbook on board at any time.

Every position stored in the cloud with latitude, longitude and time (UTC), while under way up to one point every 2 seconds. On request further data types are added to each point, for example speed over ground, wind or water temperature.

48 hours. The link opens the file without signing in, so you can share it with family and friends.

No, only the boat's owner can export.

No. What the Hub has already transferred to the cloud is exported; you only need internet on your phone or tablet.

No. The logbook lives on the Hub and works on board without internet, without an account and without a subscription.

Casting off and arriving with the type of berthing, engine on and off, for sailing boats tacks and gybes, your autopilot and every change to the anchor watch and battery alarm. You set your own entries on board via "+". On motorboats the app shows "Drifting" instead of "Sailing" from 1.48.0 and hides tacks and gybes.

On board, connected to the Hub: swipe the entry to the left and tap "Delete entry". For five seconds you can bring it back with "Undo".

Yes, from 1.48.0. On board tap "+" and then "Refuelled" or "Maintenance"; the app prefills the engine hours per engine if your engine sends them to the NMEA 2000 network. For an earlier point in time you use "Custom Entry" and choose date, time and type there.

Yes, if you connect the Hub to the cloud. You add notes and change them including their importance, also after the trip; this works for your own boat.

Yes, with all notes. They cannot change anything.

Every 5 minutes and after every change, the Hub recalculates the last 72 hours and brings the entries into a consistent order. This is intended and runs on board on the Hub, without internet and without a subscription.

On board, set an entry of your own at the right time, for example "Sailing" or "Engine off", via "+" › "Quick Entry" or "Custom Entry". What you enter yourself always applies, and the Hub adjusts the detected entries around it.

No. What you delete, the Hub does not enter again. For five seconds you can bring back a deleted entry with "Undo".

Delete the arrival in the middle of the trip. The next departure then disappears, and both trips become one.

No. Deleting and adding entries only works on board, connected to the Hub. You also write notes remotely.

For sailing boats: swipe a tack or gybe aside in the logbook and tap "Maneuver". Or tap a tack or gybe symbol on the map.

It shows how many seconds a tack against the wind cost you. 0 means no loss, minus 20 means 20 seconds lost, a positive value means you even gained height in the tack.

By how many degrees your course over ground changed, from the leg before to the leg after the manoeuvre. For tacks a small angle is green, an angle around 90 degrees yellow and a large one red.

For wind angles, ground wind and tack score, yes. The Hub's GPS supplies course over ground, its motion sensor supplies heel and sea state.

Either a wind sensor is missing, or the tack had no gain in height, for example with an avoidance manoeuvre or a circle.

Yes, if you connect the Hub to the cloud and they are your Boat Buddies. Without a subscription this applies to the manoeuvres of the last 3 months, with the Standard subscription to all manoeuvres permanently.

Connect your phone or tablet to the Hub, open Menu › "Ship's Log" and tap the PDF symbol. Choose the period, position reports if you like, and tap "Generate"; then the share menu opens with the PDF.

No. The PDF is created on board without internet, without an account and without a subscription.

In UTC. Every page carries the note "All times are shown in UTC."

Additional rows with time, location and speed over ground that the Hub adds every 10, 30 or 60 minutes while your boat is moving. By default they are switched on, with 30 minutes.

No, you create the PDF on board, connected to the Hub. Remotely you export your track as a GPX file.

Check that the Hub is reachable during the whole creation. For a very long period with a short interval, choose a shorter period or a longer interval.

For sailing boats: the Hub detects every tack and gybe itself from the apparent wind and writes it into the logbook with time and place, without a button press and without internet. About 30 to 40 seconds after the manoeuvre the line appears in the logbook.

For this it needs a wind sensor on the onboard network that supplies the apparent wind. Without a wind sensor the Hub detects no manoeuvres, and there is no message about it. If your boat is set up as a motorboat, the app shows no tacks and gybes from 1.48.0.

Tacks and gybes only stay in the logbook if you are sailing; if the engine is running, the Hub clears them away again. If the engine was wrongly detected as "on", you enter "Sailing" or "Engine off", and the manoeuvres come back.

Yes, on board via "+" › "Quick Entry" › "Tack" or "Gybe". Your entries always stay, even under engine.

On board, swipe it to the left in the logbook and delete it. The Hub does not enter a deleted manoeuvre again.

Yes, as tack and gybe symbols at the place of the manoeuvre. Tapping opens the manoeuvre analysis.

No. The Hub detects by itself when your boat casts off and when it is berthed again, and enters both with time and place. Its built-in GPS and motion sensor are enough for this, without internet and without a subscription.

The Hub continuously evaluates the last 15 minutes. A departure therefore appears in the logbook after about 8 minutes, an arrival after about 23 minutes; it sets the entry's time back to the approximate real moment.

Yes, it distinguishes "Anchored" and "Docked" by the way your boat moves. You enter "Moored" for a mooring and, on sailing boats, "Motor sailing" yourself via "+" › "Quick Entry".

On board, connected to the Hub, you swipe the entry to the left in the logbook and delete it. Then you set the correct entry via "+" › "Quick Entry"; your own entries always take priority.

Yes, if you connect the Hub to the cloud: you and your Boat Buddies get a push notification with boat name and place when you cast off and arrive. Without a subscription the Hub needs internet over Wi-Fi for this, with the Standard subscription it also works over Hub cellular.

Yes. The watch runs on the Hub, even if your phone is off: Hub alarm, alarm output, LED, notice in the app and logbook all work fully on board, without internet, without an account and without a subscription. For the push notification you connect the Hub to the cloud, and it needs internet.

Connect the app to the Hub, tap on the water next to your boat on the chart, at most 100 m away, and tap "Set Anchor Watch". The app suggests the circle, then you adjust it between 10 and 100 m.

If your boat leaves the circle for more than 15 seconds, the Hub beeps without pause and switches its alarm output, and the app on board shows the alarm. As the owner you also get the push notification "Anchor alarm!" if the Hub is connected to the cloud and has internet.

Yes, if you connect the Hub to the cloud: without a subscription if the Hub has internet over Wi-Fi, with the Standard subscription also over Hub cellular. On your phone you need the Smartboatia app version 1.30 or later, signed in and with notifications allowed.

Yes, to the Hub's alarm output, which switches in the same rhythm as the buzzer. It delivers at most 500 mA at the voltage of your boat's electrical system; for larger signal devices use a relay.

Yes, as geofencing: set it on the pontoon or at the mooring just like at anchor. Your onboard electronics may be off, the Hub then uses its built-in GPS.

Yes, with the battery alarm. The Hub measures the voltage it is supplied with every second; if it stays below your value for 30 seconds, it gives ten long tones, switches the alarm output, shows a notice in the app on board and writes to the logbook.

On board, connected to the Hub, under Menu › "Alarms" on the "Battery" card. You enter a value between 8 and 28 V and later change it with the arrows in steps of 0.1 V.

No, as long as the voltage dip is shorter than 30 seconds.

Yes, if you connect the Hub to the cloud and it has internet: without a subscription over a Wi-Fi with internet, with the Standard subscription also over Hub cellular. On your phone you need the Smartboatia app version 1.30 or later, signed in and with notifications allowed.

The battery the Hub is supplied from, because the voltage is measured at its power connection. The alarm does not use the state of charge, individual battery banks or data from a battery monitor on the NMEA 2000 network.

Yes. Switch and value are kept, and the alarm resumes watching immediately.

Anchor alarm, GPS loss of the anchor watch, battery alarm and a storm warning from the air pressure trend, each with alarm sound and vibration. For sailing boats, new trim recommendations are added, plus notices about Hub updates and, if you set it up, detected logbook entries to confirm.

Every 5 minutes the app compares the air pressure from the Hub with the value one and three hours ago. If it falls or rises by about 2 hPa in one hour or 6 hPa in three hours, "It's getting stormy!" appears. It is only available on board, not as a push notification, and it does not replace a weather forecast.

No. The notices only appear when the app is open and connected to the Hub. Otherwise the Hub on board and the push notification warn you.

Under Menu › "Alarms" the anchor watch and the battery alarm each have a bell. With it you switch off the sound on this phone or tablet; the notice still appears, but silently, and the Hub beeps as usual.

Tap the picture of your boat in the menu. The last 500 notices are listed there, newest first, and a counter shows unread ones.

Yes, under Settings › System › "Detected logbook entries": Status, Maneuvers, Engine, Alarm events and Autopilot. Only "Engine" is switched on by default.

Sign in to the app with your Smartboatia ID and allow notifications in the prompt of your phone or tablet. If you declined, you switch them on later in your device's settings for the Smartboatia app, on the iPhone under Settings › Notifications › Smartboatia.

When your boat casts off or arrives, when the anchor watch or battery alarm triggers or gives the all clear, and when someone invites you to a boat or answers your invitation. For this you connect the Hub to the cloud. From version 1.48.0 water level alert notifications are added, and for those you do not need a Hub.

Yes, if the Hub has internet over Wi-Fi, for example over the marina Wi-Fi. With the Standard subscription they also arrive over Hub cellular if there is no Wi-Fi.

No. Boat Buddies get push notifications for casting off and arriving; anchor and battery alarms go to you as the owner.

On up to five phones or tablets with your account. If you sign in on a sixth, you choose which device is removed.

According to the app's safety notice, notifications can fail to arrive or arrive up to 5 minutes late if the connection is missing or unstable. If your phone is offline, the notification arrives as soon as it has a network again.

No. Water level alerts are tied to your Smartboatia ID. You only need the Smartboatia app from version 1.48.0 and a sign-in, no boat and no Hub.

Official gauges in Germany (136 BSH gauges on the North Sea and Baltic Sea), in the Netherlands (about 183 Rijkswaterstaat locations, also on rivers and the IJsselmeer), in Norway (33 permanent Kartverket gauges, also on Svalbard) and in Finland (14 gauges of the Finnish Meteorological Institute, also on Åland).

Each gauge shows the water level in the height reference of its source: Normalhöhennull in Germany, Normaal Amsterdams Peil in the Netherlands, chart datum in Norway, theoretical mean water level in Finland. Smartboatia does not convert, so your thresholds also apply in this reference.

Some locations do not measure themselves but only have an official forecast; there the alerts are based on the forecast. For some locations the BSH only publishes values at times, for example during storm surges. As soon as a forecast arrives again, the gauge alerts normally again.

Without a subscription one gauge with all features, with the Standard subscription as many as you like. What counts is a Standard subscription you bought with your Smartboatia ID. If the Standard subscription ends, all gauges stay saved, and the gauge at the top of your list is then the one monitored.

No. They are an advisory service without guarantee: the official data arrives with a delay, forecasts can be off, and push notifications can arrive late or not at all. The official warnings of BSH, Rijkswaterstaat, Kartverket and FMI are authoritative.

Open Menu › "Smartboatia ID" › "My Fleet" › your boat, tap the person-with-plus symbol next to "Pending invites", enter the email address and choose the language of the invitation. The invited person does not need an account yet.

Up to 3 without a subscription, up to 25 with the Standard subscription. The subscription assigned to the boat counts, and open invitations also take up a place.

No. They need a Smartboatia ID with the email address the invitation was sent to, and internet. How up to date their view of your boat is depends on your boat's subscription.

Your boat live on the chart, Dashboard, boat monitoring, the entire history and your logbook with notes, including from before the invitation. Everything is read only, a Boat Buddy cannot change anything.

Yes, when your boat casts off or is berthed, with the place and boat name. Boat Buddies do not get a push notification for an anchor or battery alarm.

Under "Boat Buddies" tap the friend and confirm "Remove {name} from this boat?". Access ends immediately, and they are not notified.