Precision Tank Monitoring Directly on Your NMEA 2000 Display

The Simarine STR2 Radar Tank Level Sender is a non-contact liquid level sensor designed for direct integration with NMEA 2000 marine electronics.

Using high-precision micro-radar technology, the STR2 measures the contents of a tank without probes, floats or other components touching the liquid. It mounts externally on top of a suitable plastic or fibreglass tank and transmits level information to compatible chartplotters, multifunction displays and other NMEA 2000 equipment.

Ideal for boats and marine installations, the STR2 provides accurate, low-maintenance monitoring of fresh water, grey water, waste water and fuel tanks.

Non-Contact Radar Technology

Unlike conventional float, capacitive or probe-based senders, the STR2 uses radar to measure the distance between the sensor and the surface of the liquid.

This means:

• No moving parts

• No sensor components inside the tank

• No contact with water, waste or fuel

• No float arms that can stick

• No probes to foul or corrode

• Consistent readings with minimal maintenance

The sender supports tank heights from 150 mm to 2000 mm and can measure through suitable non-metallic tank walls up to 10 mm thick. Simarine

Native NMEA 2000 Integration

The STR2 publishes tank information using the standard NMEA 2000 Fluid Level PGN 127505.

Tank level data can be displayed on compatible:

• Marine chartplotters

• Multifunction displays

• Digital instrument displays

• Vessel monitoring systems

• Other equipment capable of receiving PGN 127505

A dedicated M12 five-pin NMEA 2000 connector allows the sender to connect to the vessel’s NMEA 2000 network without requiring a separate converter or analogue interface module.

Tank instance, fluid type and capacity are configured through the Simarine Connect app.

Please note: Formal NMEA 2000 certification is currently listed by Simarine as pending. Display support for different fluid types can vary, so compatibility with PGN 127505 should be confirmed for your particular chartplotter or MFD. Simarine

Bluetooth Configuration

The free Simarine Connect app provides wireless setup, calibration and device management.

Available functions include:

• Bluetooth pairing

• Automatic tank-height detection

• Tank name, capacity and fluid-type configuration

• NMEA 2000 tank-instance configuration

• Calibration for irregularly shaped tanks

• Firmware updates

• Device monitoring and management

Multiple calibration points can be entered to provide more accurate volume information for tanks with tapered, curved or otherwise non-standard shapes.

Suitable For

The STR2 can monitor:

• Fresh-water tanks

• Grey-water tanks

• Waste-water tanks

• Fuel tanks

For plastic or fibreglass tanks, the sender mounts externally on a flat, rigid section at the top of the tank. The sensor must be positioned horizontally with a clear, perpendicular view of the bottom.

For metal tanks, the optional Simarine S5 Metal Tank Adapter is required. The adapter creates a suitable non-metallic opening through which the radar signal can pass.

Simple External Installation

Because the STR2 measures through the top of a suitable non-metallic tank, no sensor needs to be inserted into the liquid.

Installation involves:

1. Selecting a flat mounting position with a clear view of the tank bottom

2. Cleaning and drying the mounting surface

3. Securing the sender using the supplied adhesive mounting

4. Connecting it to the NMEA 2000 network

5. Configuring the tank through the Simarine Connect app

The adhesive requires approximately 24 hours to reach full bonding strength, although wiring and configuration can be completed immediately after mounting.

Key Features

• High-precision non-contact micro-radar technology

• Native NMEA 2000 Fluid Level PGN 127505

• Direct connection to compatible NMEA 2000 displays

• Dedicated M12 five-pin male connector

• Measures through suitable plastic and fibreglass tank tops

• No probes, floats or moving parts

• Bluetooth setup and monitoring

• Automatic tank-height detection

• Multi-point calibration for irregular tanks

• Firmware updates through the Simarine Connect app

• Internal filtering for stable readings

• IP67-rated sealed housing

• Low-profile design

• Three-year manufacturer’s warranty

• Designed and manufactured in Slovenia

Technical Specifications

• Model: Simarine STR2

• Measurement Principle: Non-contact micro-radar

• Supported Tank Height: 150 mm to 2000 mm

• Measurement Accuracy: ±2%

• Resolution: Approximately 7 mm

• Near-Field Dead Zone: Approximately 10 mm from the radar face

• Maximum Non-Metallic Tank-Wall Thickness: 10 mm

• Supply Voltage: 8 to 35V DC

• Current Consumption: Approximately 14 to 20 mA at 12V

• Sensor Sampling Frequency: 1 Hz

• NMEA 2000 Update Rate: Approximately 0.5 Hz

• NMEA 2000 PGN: 127505 Fluid Level

• Network Connection: M12 five-pin male connector

• Bluetooth Connectivity: Simarine Connect app

• Operating Temperature: -20°C to 70°C

• Protection Rating: IP67

• Approximate Diameter: 62 mm

• Approximate Height: 32.5 mm

• Mounting: External top mounting

• Warranty: Three years

• Country of Manufacture: Slovenia

Compatibility Information

The STR2 is intended for compatible NMEA 2000 chartplotters, multifunction displays and monitoring systems that support PGN 127505 Fluid Level.

The STR2 does not provide analogue resistance or voltage outputs. Customers requiring 0–190 Ω, 240–33 Ω or 0–5V outputs should select the Simarine STR1 Analogue Radar Tank Level Sender instead.

The STR2 is also not compatible with the Simarine PICO, including systems fitted with the Simarine NMEA 2000 Gateway. Tank information should be viewed on a compatible NMEA 2000 display or MFD.

Perfect For

• Boats and yachts

• Marine fuel tanks

• Fresh-water systems

• Grey-water systems

• Waste and holding tanks

• NMEA 2000 vessel networks

• Chartplotter-based tank monitoring

• New marine installations

• Upgrades from mechanical tank senders

The Simarine STR2 provides a modern alternative to conventional mechanical tank senders, combining maintenance-free radar measurement with direct NMEA 2000 integration and straightforward Bluetooth configuration.