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Marine 4™


A robust and accurate portable gas detector, the Marine 4™ provides unrivaled protection in confined space applications, with audible and visual alarms in the event of exposure to flammable or toxic gases.


  • Robust and accurate portable gas detector – IP67 rated
  • Provides audible and visual alarms in the event of exposure to flammable or toxic gases
  • Detects and displays up to 4 gases simultaneously
  • Simple 1-button operation
  • ‘Crew-safe’ fail-safe sensor technology with 6-month data logging
  • MED/ Type Approved

Marine 4™ Gas Monitor


A robust and accurate portable gas detector, the Marine 4™ provides unrivaled protection in confined space applications, with audible and visual alarms in the event of exposure to flammable or toxic gases. Detecting and displaying up to 4 gases simultaneously, it is suitable for a host of applications in a variety of industries. The Marine 4™ can be configured to detect a combination of methane, oxygen, carbon monoxide, hydrogen sulphide, as well as other flammable gases.


Pre-entry checking can be carried out with the optional internal sampling pump and diffusion operation, ensuring maximum battery life in confined spaces. It has been MED “Wheel marked” for use on all vessels with a simple 1-button operation. The Marine 4™ is supplied with an integral pump with flexibility for pre-entry into deep tanks, holds and void spaces. This makes the Marine 4™ a personal and portable gas detector.

Crew Safe

The Marine 4™ has ‘crew-safe’ fail-safe sensor technology. The detector is robustly constructed and built to last on ships. Crews can also easily change the sensor, saving service time and money.



SOLAS Chapter XI-1/7 has seen the addition of regulation:

Every ship to which Chapter 1 applies shall carry an appropriate portable atmosphere testing instrument or instruments. At a minimum, these shall be capable of measuring oxygen concentrations, flammable gases or vapours, hydrogen sulphide and carbon monoxide. Instruments carried under other requirements may satisfy this regulation. Suitable means shall be provided for the calibration of all such instruments.

Marine 4™ Guides and Resources

Please see the latest guides and resources for our portable gas detectors. Learn more about portable gas detection and which vessels it’s important for.

Marine 4™ FAQ’s

Please see below the most common questions we’re asked about the Marine 4™ from our customers. If you need to know anymore, then please get in touch with our friendly team using the form below.

How big is the Marine 4™?

The Marine 4™ Gas Monitor is 21 x 59 x 32mm (4.8” x 2.3” x 1.3”) and weighs 230g (80oz) with the pump. Without the pump, it weighs 215g (7.6oz).

What is the alarm feature on the Marine 4™?

The alarm features a highly visible flashing LED and piercing >90dB audible sound.

What is battery life for the Marine 4™?

When used in diffusion mode, the Marine 4™ gas detector can operate for up to 14 hours on a single charge. It takes less than 4 hours to charge the device. 


Various factors can impact the battery life of a device. These include the ambient temperature, frequency of usage, the type and number of sensors in use, and the GPS and cellular coverage. 

Extreme hot and cold temperatures can affect the battery’s performance and capacity. Additionally, frequent alarms and active alerts can drain the battery more quickly. Some sensors may also use more power, impacting the battery drain.

In situations where GPS or cellular functions are used, poor coverage can cause the device to consume more power while attempting to maintain a connection. It is essential to keep in mind that while the battery life is rated for up to 14 hours, the actual run-time may vary depending on various factors, including the age of the battery and the specific environmental conditions in which the device is being used. Regular maintenance and proper charging practices help maximise battery life.

How often does the Marine 4 need to be calibrated for accurate readings?

The Marine 4 portable gas detector needs an annual calibration to ensure accurate readings and reliable performance. However, if you are using it on a tanker or vessel with high levels of stored gas, which increases the risk, it is recommended to calibrate the device at more frequent intervals, at least every six months.
It is further recommended that regular bump testing be performed, especially before each use of the Marine 4, to verify the response and alarm functions. Bump testing is a quick and straightforward procedure that involves brief exposure of the sensors to gas, whereas full calibration is a more thorough process.

What maintenance is recommended for the Marine 4 to ensure it operates effectively?

Regular Maintenance of the Marine 4 gas detector is advised to ensure that. 

To help you maintain your gas detector, here are some maintenance recommendations;

Daily Maintenance:

Cleaning: Regular cleaning is essential. Use cold water and a sponge for daily cleaning. If the gas detector becomes particularly dirty, clean it sooner than the scheduled full clean.

Sensor Check: Ensure all sensors sit at 0ppm (or 20.9% for oxygen) as part of the daily check.

Avoid Harmful Products: Certain cleaning products can damage the gas detector. Avoid lubricants, rust inhibitors, glass and window cleaning solutions, citrus-based cleaners, alcohol-based cleaners, hand sanitisers, products containing methanol, anionic detergents, silicones, and aerosols.

Monthly and 6-Monthly Maintenance:

Full Clean: Plan for a comprehensive cleaning at least on a monthly schedule.

Service Intervals: Regular servicing is recommended every six months due to the sensor technologies used. This helps ensure accurate measurement of gas concentrations.

Additional Maintenance Tips:

Bump Testing: Perform a bump test after each clean and before every use to verify the proper response and alarm function.

Calibration: Calibrate the gas detector in line with the manufacturer’s recommendations. The recommended calibration period for most gas detectors is six months, although this may need to be more frequent in environments with continual exposure to target gases.

Avoid Contamination: When cleaning any components of the gas detection equipment, do not use solvent-based or hydrocarbon products, as these can contaminate the sensors and cause spurious readings.

Check Auxiliary Equipment: Inspect for dents, kinks, bends, blockages, and holes in the sample probe, as well as damage to the battery, casing, display, and alarms. Ensure air inlet filters are clean for unrestricted airflow.

Training: Ensure all users are trained on correctly using the gas detection equipment, including how and when to perform bump tests.


Register Your Interest

Get in touch now to register your interest in the Marine 4™ Portable Gas Monitor. Our friendly, professional team is waiting to help you with all your enquiries about gas detectors.

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