Real prices. 3-year totals. No pretending subscriptions don't exist.
Every vendor lists a headline price. Almost none show you what the system actually costs after three seasons of cellular fees, battery-sensor refreshes, or chart-update subscriptions. We added it up for you.
Remote monitoring systems
— cellular-connected base units with service plans
| Product | Hardware | Annual service | 3-yr total | Connectivity | NMEA 2000 | |
|---|
| Siren 3Siren Marine / Yamaha | $300 | $225 | $975 | 4G/5G LTE-M | Yes, built-in | Source ↗ |
| Siren 3 ProSiren Marine / Yamaha | $800 | $225 | $1,475 | Global 5G LTE-M | Yes, NMEA + CAN | Source ↗ |
| ArmIt MaxArmIt Marine | ~$130 / sensor | $70 | ~$340 / sensor | Cellular (built-in) | No — standalone | Source ↗ |
| Sense4Boat kitLokket / Sense4Boat | €200–400 est. | ~€50 | ~€350–550 | Sigfox 0G | No — standalone | Source ↗ |
| Yacht Sentinel 6Yacht Sentinel | ~£500 | ~£140 | ~£920 | Cellular + sat option | Yes, optional | Source ↗ |
| Nautic Alert Insight X2Nautic Alert | ~$1,800 | Iridium from ~$300 | ~$2,700+ | Iridium + cellular | Yes, full integration | Source ↗ |
Siren 3
Siren Marine / Yamaha
$9753-yr total
Hardware$300
Annual service$225
Connectivity4G/5G LTE-M
NMEA 2000Yes
Siren 3 Pro
Siren Marine / Yamaha
$1,4753-yr total
Hardware$800
Annual service$225
ConnectivityGlobal 5G LTE-M
NMEA 2000Yes
Hardware~$130
Annual service$70
ConnectivityCellular
NMEA 2000No
Individual wireless sensors
— add-on sensors that pair with base units above
| Sensor | Price | Battery life | Works with | |
|---|
| Siren 3 wireless bilgeSiren Marine | ~$140 | Multi-year, replaceable | Siren 3 / 3 Pro | Source ↗ |
| Siren 3 wireless batterySiren Marine | ~$140 | Multi-year | Siren 3 / 3 Pro | Source ↗ |
| BilgeMaxArmIt Marine | $130 | ~3 years (AA) | Standalone cellular | Source ↗ |
| MotionCam ProArmIt Marine | $280 | Battery, photo-alert | Standalone cellular | Source ↗ |
Siren bilge sensor
Siren Marine
~$140
BatteryMulti-year
Works withSiren 3 / 3 Pro
Battery~3yr (AA)
Works withStandalone
Chartplotters & multifunction displays
— 9-inch class, entry-level helm units
| MFD | Street price | OS / platform | Built-in radar | Chart subscription | |
|---|
| Axiom 9Raymarine | ~$900 | LightHouse 4 | Add-on | Included + LightHouse | Source ↗ |
| ECHOMAP UHD2 9Garmin | ~$800 | Garmin marine OS | Add-on | Navionics+ ~$100/yr | Source ↗ |
| Zeus S 9B&G | ~$1,200 | NOS | Add-on | C-MAP included | Source ↗ |
| NSS evo3S 9Simrad | ~$1,400 | NOS | Add-on | C-MAP included | Source ↗ |
| NavNet TZtouch3 9Furuno | ~$2,300 | TZ Cloud | Add-on | TZ charts, tiered | Source ↗ |
| Orca Core + DisplayOrca | ~$900 | Orca OS / mobile | No — mobile/AIS | ~$200/yr premium | Source ↗ |
OSLightHouse 4
ChartsIncluded
OSGarmin Marine
ChartsNavionics+ ~$100/yr
The open-source stack
— DIY-build a connected boat for less than a season of marina fees
| Component | Cost | Role | Subscription | |
|---|
| Raspberry Pi 5 + case + SDHardware | ~$120 | The brain | — | |
| OpenPlotter OSCommunity | Free | Boat OS bundle | — | Source ↗ |
| Signal K ServerCommunity | Free | Data hub & API | — | Source ↗ |
| OpenCPNCommunity | Free | Chartplotter | Free NOAA / optional | Source ↗ |
| PyPilotCommunity | Free | Autopilot software | — | Source ↗ |
| iKonvert NMEA gatewayDigital Yacht | ~$240 | NMEA 2000 ↔ USB/SignalK | — | Source ↗ |
| SensESP (ESP32)Community | ~$15 / sensor | DIY custom sensors | — | Source ↗ |
| Typical build — 3 year totalPi + gateway + 3 custom sensors | ~$405 | Full smart boat | $0/yr ongoing | |
About these numbers.
- Prices shown are US MSRP or typical street prices at the time of publication (April 2026). Currency shown as listed by the vendor — your actual cost will vary by region, dealer, and promotions.
- 3-year totals assume continuous year-round cellular service where applicable and do not include installation labor, additional sensors beyond the base bundle, or chart updates unless noted.
- Some vendors offer seasonal (6-month) plans that materially reduce the 3-year cost — Siren's seasonal plan, for example, is $150/yr if you lay up from November through April.
- MFD category pricing is for the 9-inch tier only. Larger screens, radars, autopilots, and transducers are sold separately and can easily double system cost.
- Open-source stack assumes existing NMEA 2000 backbone and standard 12V power. Time investment is significant — this is the hobbyist's path, not the shortest one.
- If you're a vendor and a price here is wrong, let us know at hello@smartboats.org and we'll correct it.
- Want the deeper analysis behind these numbers? See our buyer's guides for Siren and other cellular monitoring systems, the OpenPlotter + Raspberry Pi open-source stack, picking a marine cellular router (Pepwave, GL-iNet), and Starlink on a boat.