SDME (JLN-740)




The JLN-740 series is a single axis water SDME compliant with the IMO MSC.96 (72) standard, required on all internationally voyaging ships exceeding 300 GT. Boasting never-before-seen accuracy for speed measurement, the JLN-740 is also installed with our company’s proprietary bubble detection function, which informs you when measurement accuracy is impaired due to air bubble contact.

The units feature a color LCD touch display for the main and sub displays, allowing you to view important information and adjust brightness on all displays from a single location.

Precise ship speed tracking

The JLN-740 series utilizes digital signal processing, which, coupled with optimizations to existing speed measurement waveforms and the reliability of ship bottom mounting, has resulted in water speed measurement with accuracy up to 0.03kn or 0.3% in all models (measured at fixed speeds)

That accuracy of information allows for highly fuel-efficient speeds, which means faster voyages with less waste. Along with improved speed measurements, the series also has greatly improved ship speed tracking, relaying all the information you need for precise navigation during berthing.

Touch operation

With just one physical power button, the 5-inch color main display and 6.5 and 8.4-inch for the remote displays are operated by touch operation. The touch screens can be easily read during daylight but also in darkness, with excellent clarity, even when viewed from a wide angle. All displays feature dimmable backlighting and have a graphical user interface is logical, easy to use and consistent throughout. All displays are designed for the industrial environment found onboard of ships, ensuring years of problem free operation.

Cost-effective operation

The doppler speed log is also available with a cost-effective 4.5-inch display with the main data displayed in large characters of easy reading. In addition that the display is fully dimmable and has backlit keys, it features dual LED backlight (white and orange) making it easy to operate in various light settings on the bridge.

Remote support

The JLN-740 supports the JRC original Remote Maintenance System (RMS), one of the core elements of JRC’s customer operations support philosophy. With the VDR connected through LAN, the JLN-740 doppler log can be monitored from shore using JRC’s FB or GX satellite communications system. This allows a cost-effective determination of the operating status, software version installed but also firmware can also be updated through J-Marine Cloud.

Distribution processor

This speed log incorporates a highly reliable interfacing field. You can easily connect a wide range of additional equipment to optimize your configuration. A second display, smaller remote displays and analog indicators are just a few of the possibilities. The JLN-740 can also output the measurement information to radar and ecdis.

Signal processor

The transducer room has a quite bad environment with regard to vibration and humidity, therefore, before signal is distributed to various equipment, the transducer is directly connected to the processor, minimizing loss of signal and extending cable length to hundreds of meters.


The transducer is compact and constructed of light weight moulded rubber, to minimize the effects on aeration, which allows stable and accurate operation.

Gate valve

Using an optional gate valve transducer allows for long-term cost saving and easy maintenance as dry docking is not necessary.

IMO compliant

The JLN-740 series is designed according to the latest IMO regulations on all internationally-voyaging vessels exceeding 300 GT and meets the standards for the IEC environmental test standards. When used with JRC’s satellite log JLN-720, ships exceeding 50,000 GT will meet the requirements for IMO MSC.334(90).

JRC is continuously developing and evaluating new products, based on future IMO requirements that will contribute to your future safety and navigation at sea.

Snap on mounting

Our standard main touch screen display and two remote displays feature our famous and unique snap on flush mount system, making it possible to fit the display without tools. The display can easily be pushed into the frame and kept in position by a click/spring system. As a result, a minimal amount of screws or mounting bolts are visible and allows for easy maintenance.

1. If used in combination with JLN-720
2. Only supported by JLN-740A/N

We are a family owned and operated business with over 100 years of experience

Please feel free to contact to discuss your requirements in more detail, we would be delighted to assist you.

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