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eXpendable Conductivity, Temperature and Depth

Product Code:XCTD

Measure the vertical distribution of seawater temperature and salinity from ships or aircraft

The eXpendable Conductivity, Temperature and Depth system is a system that performs seawater measurement by deploying a probe. It can be used to perform measurement even in poor sea conditions. It makes it easy to perform sea temperature and salinity profile observation even on vessels without observation equipment.


The XCTD can be used to perform measurements from various platforms.

Dropping the probe into the sea using a hand launcher

Dropping the probe into the sea using a hand launcher.

  • The XCTD system measures the vertical distribution of water temperature and salinity.
  • XCTD water temperature detection is performed using a high performance disk thermistor. Changes in water temperature are measured through the changes in the thermistor’s resistance. The XCTD system determines salinity by performing calculations using electrical conductivity data and water temperature data.


Item Temperature Conductivity
Range -2~35℃ 0~60mS/cm
Accuracy ±0.02℃ ±0.03mS/cm
Resolution 0.01℃ 0.015mS/cm

XCTD probe & XBT probe


Type Measuring Depth (m) Ship Speed (knots) Measuring Time (sec.)
XCTD-1 1000 12 300
XCTD-2 1850 3.5 575
XCTD-3 1000 20 205
XCTD-4 1850 6 540
  • The above specification values are reference values, and are subject to change without prior notice.

XCTD systems shipped from April 2021 have a new XCTD probe design.

New XCTD label

Please review the changes resulting from the changes to the XCTD’s circuit board and the procedures for checking and updating the Windows software in order to be able to use the new XCTD.


Inquiries regarding eXpendable systems

Please provide the following information when contacting us with inquiries.

  • Type of probe used
  • Serial number
  • Converter/launcher configuration