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Boat Monitor

  • Monitor unwanted access and feel safe even when moored outside the marina. Be alerted in seconds of unauthorized access and eventual movement of your boat.
  • Prevent battery damage. Be alerted when a battery's voltage drops below nominal. Monitor up to 4 batteries.
  • Log your trip. Keep track of all your routes, mileage, duration and speed. Share your adventures on social media!
Img boat main

What's included

  • Boat Monitor device
  • Sentinel app
  • First year subscription

Request a quote

We will get in touch with you with a customized quote, based on your specific needs.

Your order was sent successfully! A member of our team will contact you to complete the purchase.

Something went wrong, try refreshing and submitting the form again or contact us at info@sentinelmarine.net.


I tried several other products and chose Boat Monitor because of its functionality and a very good app. The accuracy and speed are amazing! It's like having my boat in my pocket. I can check all data in real-time and Boat Monitor keeps my boat safe when I'm not onboard.
Nejc Končan Verstovšek

How it works

  1. Connect to battery

    1. Connect to battery

    The installation is easy. Follow a few simple steps to connect Boat Monitor to your boat battery.

    Boat monitor consumes very little power. Its impact on your boat battery should not be noticeable.

  2. Connect sensors

    2. Connect sensors

    Optionally, connect Boat Monitor to up to 3 additional batteries, the bilge pump and the included magnetic sensor.

    Congratulations! You are all set to start using your Boat Monitor!

  3. Activate with smartphone

    3. Activate

    Download the Sentinel app and use it to activate your Boat Monitor.

    Within minutes you see your boat's position and the status of the batteries and bilge pump in the app. You can also configure alerts for geofence and any sensors you installed. Your trips will be automatically added to the journey log.

  4. Upgrade with more sensors

    4. Upgrade with more sensors

    Upgrade your Boat Monitor with additional sensors. Choose between motion sensor, temperature and humidity sensor, water-level sensor, shunt, shore power and others.

    Use the app to enable or disable alerts for each sensor.

Download the Sentinel App for your smartphone!

Download the Sentinel Marine app for iOS Download the Sentinel Marine app for Android


Low battery alert

Boat Monitor sends you a real-time mobile notification when the battery voltage drops below nominal. Avoid getting stuck in a remote location without power.

Boat Monitor can monitor up to 4 batteries and measure current providing you with an idea of power consumption.

App boat battery


Bilge operation notification

Water is all around us and sometimes boats leak. Boat Monitor sends you a mobile notification when the bilge pump starts running.

App boat bilge


Journey log

Keep track of all your past routes, mileage, duration and speed. Your trips are automatically added to the journey log.

Share your adventures with friends and family on social media and let them follow you in real-time!

App boat routes


Geofence alert

Activate the geofence alert and receive a push notification when your boat moves from its position. Safeguard your boat against the anchor not holding ground, strong currents and thieves.

GPS tracking will help you to quickly locate your boat in the event of theft.

App boat geofence


Intrusion detection

After leaving your boat, activate extra sensors and be alerted of unwanted access at any time.

If you installed the included magnetic sensor, it will alert you of window/door opening. For more security, connect a motion sensor or connect Boat Monitor to your engine to detect ignition.

App boat intrusion


NMEA2000 compatibility

Connecting Boat Monitor to a NMEA2000 network lets you observe wind speed, temperature, engine RPM and other boat instruments' data.

App boat nmea

Why choose Boat Monitor

  • Easy installationBasic installation is complete in less than 30 minutes.
  • Low current drainBoat Monitor will not deplete your boat battery.
  • UpgradableSupports vast array of sensors.
  • NMEA2000 support Built-in access to instrument and motor data.


Technical specification


Dimensions: 100 mm x 100 mm x 40 mm
Weight: 500 g


- Wide supply voltage range: 11V to 30 V DC (12 V and 24 V systems)
- Does not drain boat battery due to low current consumption:

  • Maximum: 300 mA (internal battery charging)
  • Nominal average: 35 mA RMS (normal operation)
  • Sleep mode: <1 mA

- Boat battery discharge protection: device disconnects from battery when voltage drops below 11 V
- Built in internal backup battery: device is fully operable after power supply is disconnected for additional 14 hours*


- 14 hours* of operation without external battery supply
- More than 30 days of operation without network connection (data is stored on internal flash memory and synchronized with the server when network connection is available)


- Excellent accuracy worldwide: supports 4 international positioning systems GPS/GLONASS/Galileo/QZSSS
- Built in high gain GPS antenna for good reception and easy installation


- Operating temperature: -25°C to +55°C
- Storage temperature: -40°C to +70°C


- 2 digital inputs (bilge, door)
- 4 analog inputs for battery voltage monitoring (supply voltage + 3 additional inputs up to 30 V)
- One differential input for current measurement - NMEA2000 compatible interface for reading boat instrument data


- GPRS modem: Works worldwide (Quad-Band GSM 850/900/1800/1900 MHz)
- Built in high gain GSM antenna for good reception and easy installation
- Bluetooth low energy (BLE) support

* Actual autonomy may vary based on signal strength and distance traveled.

About Boat Monitor

Why do I need Boat Monitor?

That’s an easy one, because there are plenty of great features you will receive from your Boat Monitor!
It provides the information about your boat’s position at any moment. Why should you worry about this? For example, if your boat is being rented, is in a charter management or if moored in a place with no additional security.
Install the magnetic contact sensor and other additional sensors, and Boat Monitor will provide you with a much higher level of security (door alert, bilge alert …).
Boat Monitor provides you with the exact information about your batteries voltage and sends you alerts in case it drops below nominal. So no worries about that either!
Additionally, if connected to NMEA2000 network, you will be able to analyze your navigation data (speed, average speed, wind and current data, etc).
With your Boat Monitor, you can share your routes with friends and family.

How does Boat Monitor actually work?

With buying our Boat Monitor you will get a small, 10 x 10 cm device, a wired magnetic sensor and one year subscription plan. The installation is easy. The few simple steps are well described in the manual and you can do it yourself.
After being properly installed, Boat Monitor device can provide data from 1 main battery, 3 extra batteries and from the bilge pump. The device itself provides current, as well as historical data about the routes and the geofence alerts. Boat Monitor comes with a magnetic (contact) sensor, that works as an intrusion detector, providing alerts in case of an unauthorized access to your boat.
If you want more security, there are plenty of add-on sensors available, wired and wireless: bilge water-level sensors, shore power detection, infrared motion sensors, shunt sensor and others. After installing the device, there is one quick final step - the activation: download the Sentinel app from the appstore, scan the QR code on the device, create an account and your device is ready to go. When the device activates, the subscription plan activates automatically, and no additional costs apply.

What is included in Boat Monitor?

Sentinel Boat Monitor device, one wired magnetic sensor and one year subscription. The device can provide data from 1+3 batteries and the bilge pump, current as well as historical data about the routes (GPS journey log), and geofence alerts. The magnetic sensor can be installed on the windows/doors as an intruder detection sensor.

Which sensors are included with Boat Monitor?

One wired magnetic sensor is already included in Boat Monitor.

What can be added to Boat Monitor?

There are plenty of sensors that can be added to Boat Monitor: additional magnetic (contact) sensor (door, windows…), infrared motion sensor, bilge water-level sensor, shore power detection, shunt sensor and others.

Which sensor would you recommend?

We recommend you the installation of the magnetic (contact) sensor, that works as an intrusion detector, providing alerts in case of an unauthorized access to your boat. This is why this sensor already comes with Boat Monitor.

Where can I buy the additional sensors?

Please contact our resellers which you can find on the website.

How precise is the GPS tracking?

GPS Tracking frequency is dynamic - it depends on whether the boat is turning, going straight or not moving at all. The resulting tracks are very detailed as can be seen in this image:
For performance reasons the points may be slightly sparser when displaying the routes on your computer, phone or tablet. You can download the full track using the "Download GPX" button on any route in the web app.

What is the difference between Boat and Fleet Monitor?

The following table highlights the main differences between Boat and Fleet Monitor

Fleet Monitor Boat Monitor
- Tailored for charter businesses and rental boats
- Must buy at least 3
- Supports measuring 2 batteries and wired sensors
- Supports report: "Gas station visit"
- Supports 12 V and 24 V batteries
- Very flexible/module design to fit a broader range of users
- Supports up to 4 batteries, and sensors, allowing users to upgrade it anytime with new sensors.
- Supports NMEA 2000 network, allowing users to capture data from your boat instruments.
- Supports 12 V, 24  and 48V batteries

Usage and Features

How to get started with your new Monitor?

  1. Make sure that you phone or table is connected to Internet
  2. Dowload the Sentinel app from the App Store or Google Play
  3. Open the Sentinel application and click on "Scan QR Code"
  4. Scan the QR code on your new Monitor device
  5. Follow the steps to Register or Login
  6. Follow the instuctions in the application to register the device
  7. The registration should now be complete. After a few minutes (sometimes up to 15mins) the device will start sending data which will be shown in you application.

Will Sentinel Boat Monitor use the power from my battery?

Yes, but very little. With a 100 Ah battery the Boat Monitor will work more than 6 months (this is without charging it).

Will Sentinel Boat Monitor still work if I switch off the battery when leaving the boat?

Yes, up to one day. But with Boat Monitor there is no need to switch off the batteries any more, since it will provide you the exact information about the battery voltage and alert you in case the voltage is low.

How much current does Boat Monitor actually use?

Boat Monitor consumes 1 Ah during a day of sailing and only 24 mAh while your boat is moored. The impact of Boat Monitor on your boat batteries should not be noticeable.

How many batteries can Boat Monitor measure at the same time?

One main battery and 3 extra batteries, 4 all together.

How will I be alerted in case something happens to my boat?

In that case you will receive a mobile push notification. You should be logged-in to the Sentinel app and have access to WiFi or 3G/4G.

Where can I get the Sentinel app?

Just download the Sentinel app from the Google Play, App store or use our web app (web.sentinelmarine.net)

How can I connect the app with the device?

Use the smartphone or tablet to scan the QR code on the Boat Monitor, and follow the instruction on screen. The process should only take you a moment.

Is it possible to share my routes on social media?

Sure, you can easily share your past or current routes with your friends and family via e-mail or on your social media.


Who will install my Boat Monitor and sensors?

It’s very easy to install the Boat Monitor yourself following the steps in the Installation guide. For installing optional wired sensors we recommend that you seek professional assistance.

Is there customer support available in case I’ll have any additional questions regarding my Boat Monitor or the installation?

Of course, we have a 24/7 support service. Please, contact us on suport@sentinelmarine.net or call +385 91 33 55 66 7. We aim to reply within a few hours.


Is the subscription mandatory to start using my Boat Monitor?

Yes. By activation the device you automatically activate the subscription plan (included subscription covers the first year of usage).

Which countries are covered by the subscription?

Depending on the subscription plan you chose your device will work in different areas, as shown in the map below.
EU coverage

  • Austria
  • Belarus
  • Belgium
  • Bulgaria
  • Croatia
  • Cyprus
  • Czech Republic
  • Denmark
  • Estonia
  • Finland
  • France
  • Germany
  • Greece
  • Hungary
  • Ireland
  • Italy
  • Latvia
  • Liechtenstein
  • Lithuania
  • Luxembourg
  • Macedonia
  • Malta
  • Netherlands
  • Norway
  • Poland
  • Portugal
  • Romania
  • Serbia
  • Slovakia
  • Slovenia
  • Spain
  • Sweden
  • Switzerland
  • United Kingdom
Worldwide coverage (including EU)
  • Albania
  • Australia
  • Azerbaijan
  • Canada
  • China
  • Congo (Dem. Rep.)
  • Egypt
  • France Caraibe
  • Gibraltar
  • Hong Kong
  • Iceland
  • India
  • Indonesia
  • Israel
  • Japan
  • Korea Rep.
  • Kosovo
  • Malaysia
  • Moldova
  • Montenegro
  • New Zealand
  • Nigeria
  • Qatar
  • Reunion
  • Russia
  • Singapore
  • South Africa
  • Sri Lanka
  • Taiwan
  • Thailand
  • Turkey
  • Ukraine
  • United Arab Emirates
  • United States
  • Vietnam

What does the subscription cover?

The entire service, you have zero additional costs. What about the next year? You will easily renew the subscription in the online shop.

Can I switch the subscription plans?

Yes. For the first year you are already covered, and for the future we are working on offering you monthly plans as well.

About Sentinel Wifi

Does Boat Monitor offer me Internet access?

No, but you can buy our Sentinel WiFi.

What do I get from Sentinel WiFi?

A WiFi router and Internet access.

How much will Internet browsing via Sentinel WiFi cost me?

Depends on your region. Please, contact us.

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