Automatic CTD Profiling System – Model APB5


  • No biofouling on sensors, OWAS principle.
  • The profiling CTD with build in Radio(868 Mhz) for communication with system.
  • Remote control for waking and stopping the APB5, and also for remote steering of winch.
  • Real-time data on webpage, accessible from various platforms via http
  • Two-way communication
  • Multi-parameters profiling measurement are stored as files, end sendt by FTP to remote server.
  • Programmable speed, depth and intermediate stops
  • Programmable profiling Intervall, configurable in various ways
  • Communication with remote system via GPRS/EDGE/LTE(4G) & satellite (INMARSAT)
  • Profiling depth: standard 75 m, extended 100, 150 and 190 meters
  • Profiling Line, type Dyneema White, 950 Kg, Ø3 mm, Pre-Stretched
  • CTD profiler with multi-parameter sensors.
  • Weather station (Optional)
  • Current speed/direction from ADCP (Optional)
  • Network protocols FTP, SMS, NTP, WIFI, HTTP
  • 32 Gbyte internal memory storage
  • 190 Watts solar panels.
  • 2.5 Kwh LifePo4 litium batteri pack.
  • Current consumption (75 meter) in Idle 0.3mA(between profiles and passive) , 1 Amp average current when doing vertical CTD profiling.

Automatic ctd profiling system

Automatic CTD profiling system for down to 200 meter


Remote control for APB5 interrupt.



Live environmental data direct on web.

The Automatic CTD profiling system, APB5 (Automatic Profiling Buoy ver. 5) is designed for monitoring water quality parameters in coastal waters, fjords, lakes, and aquaculture installations. It consists of a self-contained, solar panel driven, remotely operated, floating buoy and a CTD (Conductivity, salinity, temperature, and depth/pressure) winch-controlled profiling probe. The standard SAIV AS CTD204/208 profiling probe can be upgraded with oxygen, fluorescence, turbidity etc. The APB5 operation system, is web-based and can be remotely configured to set profile intervals, depth, and speed of profile. The APB5 buoy can also be equipped with a Weather Station (GPS, wind speed, wind direction, air temperature) and a ADCP (Acoustic Doppler Current Profiler). The standard profiling depth is 75 meters, but can be extended to 190 meters. The resolution of the profile is based on the configuration of the chosen measuring intervals and the speed of the winch.

The unique OWAS (Out of Water Antifouling System) feature prevents bacterial and algae growth on the probe and its sensitive monitoring sensors, which minimize cleaning maintenance for extended periods of operation. The unit can easily operate autonomously for a full year in between service procedures.

The APB5 buoy contains a control unit (CU801B) with embedded webserver, a 4G WIFI router (GSM/GPRS/EDGE/LTE), a winch, a short-range radio for data transfer and communication with the CTD probe, solar cells, and a battery pack.  A satellite router (IMARSAT Fleetbroadband 150) can be added for use in locations without mobile coverage. In case a satellite connection is required the APB5 can be upgraded to the APB5-HD (Heavy Duty) version.

Wireless communication with the CTD probe.

The new CTD profilers from SAIV AS model SD208 and SD204 has an inbuilt low-power, short-range radio, operating at the frequency 868Mhz.  This enables wireless data communication between the instrument and the control unit since the profiling CTD Multi parameter probe is suspended inside the buoy and out of water between profiles. It also assures that in between profiles the CTD probe is constantly calibrated with the ambient air pressure and oxygen concentration. In addition, the unique wireless communication system also makes cable connections to the probe redundant, which significantly reduces weight, power demand, and troublesome slip-ring connections in the winch. The profiling probe is simply hanging from the winch by a strong light nylon rope. All this ensures that power consumptions are very low. For example, the CTD profiling probe can operate continuously for 1 year, doing 40 m depth profiles every 2 hours, with a winch speed of 6 seconds per meter, and a measuring interval of 10 seconds.


Link to the Data acquisition pages: This is the default server that is free of charge for all APB5 system: The page shows real time data from an APB5 unit in operation. The page also has a FTP  (File Transfer protocol) which enables access to all profile files that is sent from a running APB5 system. Users can make their own presentation on various platforms. It also contains (graphs, videos, article, software and data sheets)

Links to a system made by a user: is a school education system, for teaching students about environmental measurements and learn how to do analyses of the data. It is a collaboration between the University of Bergen (NORWAY) and a nearby college, and the project is called "Ekte data" translated (Realdata)

Link to another custom made user system:
welfare in aquaculture is an aquaculture surveillance system that was developed by the Institute of Marine Research (IMR) in Bergen. The picture on the welfare meter is showing an earlier version of the automatic profiling buoy (APB4), which was replaced by APB5 in 2012.


Embedded Web Server CU801B

GSM/GPRS/EDGE/LTE(4G)/WIFI router, or satellite router (Inmarsat 150 fleetBroadband)

Winch control unit and motor

2 * 14.4 Volt (1250 Kwh) lithium battery pack

Solar Cells: 190 Watt

Free server space and configuration at : (or custom)

Configurable via internal Webpage and Remote

Programmable Profiling interval, depth etc.

Profiling Depth Range: Standard 75 m /Extended 100, 150 and 190m

868 MHz Radio controllers for instrument communication

Transparent communication to all devices in the buoy and sensor unit for diagnostic purpose etc.

User to provide SIM card.

Data is presented instantaneously on Internet after a ended vertical profile

Optional Weather station:  type Airmar 150 wx

Optional ADCP (Acoustic doppler current profiler) : type Nortek

Mooring points: 4 shackle points at lower buoy section,

Anchoring: 3-4 anchors (depending on conditions)

Weight of complete buoy in air 200 kg. When in water it will add 300 kg of water as ballast.

Download datasheet as PDF