Speed Log (JLN-740)

Speed Log

  • Highly accurate speed and distance log
  • 5-inch color touch display
  • Proprietary bubble detection
  • 10.8VDC to 31.2VDC


The JLN-741A 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 JLN-741A 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.

A long-unsolvable problem with doppler-based water speed measuring systems was reduced accuracy from bubbles making contact with the measuring device on the bottom of the vessel. The JLN-741N series detects when bubbles contact the transducer, and using roprietary technology from JRC alerts you of reduced measuring accuracy via the display. Confirming the source of the issue typically requires visually examining the device on the bottom of the ship. However, onboard air bubble detection allows you to skip unnecessary preventive maintenance.

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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