Product Selection Guide

A CTD measures Conductivity, Temperature, and Depth. Despite the name, all CTDs actually measure pressure, which is not quite the same thing as depth. The relationship between pressure and depth is a complex one involving water density and compressibility as well as the strength of the local gravity field. The CTD data can be used to calculate salinity, density, sound velocity, and other parameters of interest. The term CTD is often used today to describe a package that includes the actual CTD as well as auxiliary sensors to measure other parameters (such as dissolved oxygen, pH, turbidity, fluorometer, altimeter, etc.) and a water sampler to collect water samples for later analysis in the lab.

Sea-Bird manufactures CTDs as well as a number of other products. Our products are categorized into a number of groups, each with unique applications:

  • Profiling CTDs: A profiling CTD measures water parameters as it travels through the water, whether lowered over the side of a ship with a winch to take measurements of a vertical column of water or integrated with an autonomous vehicle or glider. Common to all Sea-Bird Profiling CTDs are purposeful designs built to perform under the unique dynamic conditions found on varying measurement platforms, pumped and ducted constant flow for matched temperature and conductivity response, measurements made on the same sample of water with a predictable delay and predictable flow effects, and aligning and coordinating measurements done with software or (for some models) automatically.
  • Water Samplers: A water sampler is often used in conjunction with a CTD. The water sampler collects 1 or more actual samples of water for analysis in the lab after recovery of the package. The water samples can be used to verify the accuracy of data measured by the instruments on the package, and/or to provide additional information that cannot be measured with an instrument in the field. Sea-Bird water samplers can be controlled (i.e., bottles closed) from deck via a Sea-Bird deck unit and software, or can be pre-programmed to close bottles at desired depths.
  • Moored Instruments: A moored instrument measures water parameters in one location, over an extended period of time, providing a time series of data. To reduce costs, a moored CTD may not include a pressure sensor, because the deployment depth is known (approximately); the pressure sensor is optional in Sea-Bird moored CTDs. Sea-Bird also manufactures moored temperature sensors as well as instruments for high-accuracy pressure measurements (wave and tide recorder, bottom pressure recorder, and tsunami sensor).
  • Inductive Modem Instruments: Sea-Bird's inductive modem uses a mooring cable as the communication link, permitting the underwater instrument(s) to be easily positioned at any depth without the use of cable connectors.
  • Shipboard Salinographs: Thermosalinographs are used to collect information about the sea surface, typically in flow-through systems operating continuously throughout a cruise. Thermosalinograph data can be used to calculate salinity, density, sound velocity, and other parameters of interest.  Thermosalinographs are usually installed inside and near to the hull of a ship in order to make measurements on uncontaminated seawater. Optionally, you can plumb other types of sensors into the system for a wider range of measurements.
  • Oxygen Sensors: Oxygen sensors measure dissolved oxygen in the water. Sea-Bird oxygen sensors are designed to be integrated with a pumped CTD.
  • pH Sensors: pH sensors measure pH (alkalinity / acidity) in the water.
  • Other Products: Sea-Bird manufactures a number of other products, including data loggers and counters, pH, CTD surface power and telemetry systems, and modular sensors and components.

Shown below are comparisons of features within each product group, to assist you in selecting the appropriate instrument for your application.

 

Profiling CTDs (Conductivity, Temperature, and Pressure)

SBE Sampling Rate Channels for Auxiliary Sensors Memory Power Real-Time Data Comments
Internal External
SBE 911plus CTD (9plus CTD & 11plus Deck Unit) 24 Hz

8 A/D

16 Mb with optional SBE 17plus V2
(with optional SBE 17plus V2)
World's most accurate, high resolution CTD, premium sensors, multi-parameter support, water sampler control.
SBE 25plus Sealogger CTD 16 Hz 8 A/D;
2 RS-232
2 Gb
May require SBE 36 CTD Deck Unit & PDIM
High-resolution logging CTD with multi-parameter support. Water sampler control with SBE 33 Carousel Deck Unit.
SBE 25 Sealogger CTD
8 Hz 7 A/D 8 Mb
May require SBE 36 CTD Deck Unit & PDIM
Replaced by SBE 25plus in 2012. Water sampler control with SBE 33 Carousel Deck Unit.
SBE 19plus V2 SeaCAT Profiler CTD 4 Hz 6 A/D;
1 RS-232
64 Mb
May require SBE 36 CTD Deck Unit & PDIM
Personal CTD, small, self-contained, adequate resolution. Water sampler control with SBE 33 Carousel Deck Unit.
SBE 19plus SeaCAT Profiler CTD
4 Hz 4 A/D; optional PAR 8 Mb
May require SBE 36 CTD Deck Unit & PDIM
Replaced by SBE 19plus V2 in 2008. Water sampler control with SBE 33 Carousel Deck Unit.
SBE 19 SeaCAT Profiler CTD
2 Hz 4 A/D 1 - 8 Mb
May require SBE 36 CTD Deck Unit & PDIM
Replaced by SBE 19plus in 2001. Water sampler control with SBE 33 Carousel Deck Unit.
SBE 49 FastCAT CTD Sensor 16 Hz      
May require SBE 36 CTD Deck Unit & PDIM
For towed vehicle, ROV, AUV, or other autonomous profiling applications. Water sampler control with SBE 33 Carousel Deck Unit.
SBE 52-MP Moored Profiler CTD & (optional) Dissolved Oxygen Sensor 1 Hz 1 frequency channel for dissolved oxygen sensor 28,000 samples   Intended for moored profiling applications on device that is winched up and down from a buoy or bottom-mounted platform.
SBE 41/41CP CTD Module for Autonomous Profiling Floats (Argo) OEM CTD for sub-surface oceanographic float that surfaces at regular intervals, transmits new drift position and in situ measurements to ARGOS satellite system. CTD obtains latest temperature and salinity profile for transmission on each ascent. Also available is a Navis Autonomous Profiling Float and Navis BGCi Autonomous Profiling Float with Integrated Biogeochemical Sensors
Glider Payload CTD (GPCTD) and Slocum Glider Payload CTD OEM CTD for autonomous gliders. Generic Glider Payload CTD (GPCTD) is modular, low-power profiling instrument that measures C, T, P, and (optional) Dissolved Oxygen. Slocum Glider Payload CTD provides retrofit/replacement for CTDs on Slocum gliders. Designs share many features, but there are differences in packaging, sampling abilities, power consumption, and installation (see individual data sheets).
Notes:
1. See Application Note 82: Guide to Specifying a CTD.
2. products are no longer in production. Follow the links above to the product page to retrieve manuals and application notes for these older products.

Elsewhere on this page: Water Samplers | Moored Instruments | Inductive Modem Instruments | Shipboard Salinographs | Oxygen Sensors | pH Sensors | Other Products

 

Water Samplers and CTD Configurations

Water Sampler Number of Bottles Bottle Size (liters) CTD Control Deployment Depth
Real-Time
Configuration
Self-Contained Configuration 
(auto bottle firing)
SBE 32 Carousel Water Sampler
(full size)
12 1.7 - 30 SBE 9plus SBE 11plus V2 Deck Unit SBE 17plus V2 Searam Recorder & Auto Fire Module

6800 m (aluminum), 7000 m (titanium)

24 1.7 - 12
36 Consult Factory
12 1.7 - 30

SBE 19 SeaCAT**
SBE 19plus SeaCAT**
SBE 19plus V2 SeaCAT
SBE 25 Sealogger**
SBE 25plus Sealogger

SBE 33 Carousel Deck Unit
(can also be used with SBE 49 FastCAT CTD Sensor)
Carousel Auto Fire Module (AFM)
(can also be used with SBE 50 Digital Oceanographic Pressure Sensor)
24 1.7 - 12
36 Consult Factory
SBE 32C Carousel Water Sampler
(compact)
12 1.7 - 8 SBE 9plus SBE 11plus V2 Deck Unit SBE 17plus V2 Searam Recorder & Auto Fire Module

6800 m (aluminum), 7000 m (titanium)

SBE 19 SeaCAT**
SBE 19plus SeaCAT**
SBE 19plus V2 SeaCAT
SBE 25 Sealogger**
SBE 25plus Sealogger

SBE 33 Carousel Deck Unit
(can also be used with SBE 49 FastCAT CTD Sensor)
Carousel Auto Fire Module (AFM)
(can also be used with SBE 50 Digital Oceanographic Pressure Sensor)
SBE 32SC Carousel Water Sampler
(sub-compact)
12 1.7 or 2.5

SBE 19 SeaCAT**
SBE 19plus SeaCAT**
SBE 19plus V2 SeaCAT
SBE 25 Sealogger**
SBE 25plus Sealogger

SBE 33 Carousel Deck Unit
(can also be used with SBE 49 FastCAT CTD Sensor)
Carousel Auto Fire Module (AFM)
(can also be used with SBE 50 Digital Oceanographic Pressure Sensor)

6800 m (aluminum), 7000 m (titanium)

SBE 55 ECO Water Sampler 3 or 6 4

SBE 19 SeaCAT**
SBE 19plus SeaCAT**
SBE 19plus V2 SeaCAT
SBE 25 Sealogger**
SBE 25plus Sealogger

SBE 33 Carousel Deck Unit
(can also be used with SBE 49 FastCAT CTD Sensor)

Built-in auto bottle firing, no additional equipment required 600 m

Notes:
1. Operation of all SBE 32 Carousel Water Sampler models with the SBE 33 Deck Unit requires serial interface in the Carousel.
2. See Application Note 45: Guide to SBE 32 Carousel Water Sampler Configuration Options for information on selecting the appropriate Carousel options for your application.
3. ** Products are no longer in production. Follow the links above to the product page to retrieve manuals and application notes for these older products.

Elsewhere on this page: Profiling CTDs | Moored Instruments | Inductive Modem Instruments | Shipboard Salinographs | Oxygen Sensors | pH Sensors | Other Products

 

Moored / Time Series Recording Instruments

SBE Measures
(C, T, P)
Auxiliary Sensors Memory Power Communication Real-Time
Data
Comments
Internal External
SBE 16plus V2 SeaCAT C-T (P) Recorder C, T, P* 6 A/D; 1 RS-232 64 Mb RS-232 Optional pump
SBE 16plus SeaCAT C-T (P) Recorder
C, T, P* 4 A/D; optional RS-232 or PAR 8 Mb RS-232 or -485 Replaced by SBE 16plus V2 in 2008
SBE 16 SeaCAT C-T (P) Recorder
C, T, P* 4 A/D 1 Mb RS-232 Replaced by 16plus in 2001
SBE 16plus-IM V2 SeaCAT C-T (P) Recorder C, T, P* 6 A/D; 1 RS-232 64 Mb   Inductive Modem Optional pump
SBE 16plus-IM SeaCAT C-T (P) Recorder
C, T, P* 4 A/D; optional RS-232 or PAR 8 Mb   Inductive Modem Replaced by SBE 16plus-IM V2 in 2008
SBE 19plus V2 SeaCAT Profiler CTD C, T, P 6 A/D; 
1 RS-232
64 Mb RS-232 Programmable mode — profiling or moored
SBE 19plus SeaCAT Profiler CTD
C, T, P 4 A/D; optional PAR 8 Mb RS-232 Replaced by SBE 19plus V2 in 2008
SBE 19 SeaCAT Profiler CTD
C, T, P 4 A/D 1 - 8 Mb RS-232 Replaced by 19plus in 2001
SBE 37-SM MicroCAT C-T (P) Recorder C, T, P*   8 Mb RS-232 or -485  
SBE 37-SMP MicroCAT C-T (P) Recorder C, T, P*   8 Mb RS-232, RS-485, or SDI-12 Integral pump

SBE 37-SMP-IDO MicroCAT C-T-DO (P) Recorder

C, T, P* Integrated DO 8 Mb RS-232 or -485 Integral pump
SBE 37-SMP-ODO MicroCAT C-T-DO (P) Recorder C, T, P* Integrated Optical DO 8 Mb RS-232, RS-485, or SDI-12 Integral pump
SeapHOx Ocean C-T-DO-pH (P) Recorder C, T, P* Integrated Optical DO, pH 8 Mb RS-232 37-SMP-ODO with SeaFET pH sensor; to 50 m
Deep SeapHOx Ocean C-T-DO-pH (P) Recorder C, T, P* Integrated Optical DO, pH 8 Mb RS-232 37-SMP-ODO with SeaFET pH sensor; to 2000 m
SBE 37-IM MicroCAT C-T (P) Recorder C, T, P*   8 Mb   Inductive modem  
SBE 37-IMP MicroCAT C-T (P) Recorder C, T, P*   8 Mb   Inductive modem Integral pump
SBE 37-IMP-IDO MicroCAT C-T-DO (P) Recorder C, T, P* Integrated DO 8 Mb   Inductive modem Integral pump
SBE 37-IMP-ODO MicroCAT C-T-DO (P) Recorder C, T, P* Integrated Optical DO 8 Mb   Inductive modem Integral pump
SBE 37-SI MicroCAT C-T (P) Recorder C, T, P*   8 Mb   RS-232 or -485  
SBE 37-SIP MicroCAT C-T (P) Recorder C, T, P*   8 Mb   RS-232 or -485 Integral pump

SBE 37-SIP-IDO MicroCAT C-T-DO (P) Sensor

C, T, P* Integrated DO 8 Mb   RS-232 or -485 Integral pump
SBE 39plus Temperature (P) Recorder T, P*   64 Mb Optional USB & RS-232 Optional  
SBE 39 Temperature (P) Recorder
T, P*   32 Mb Optional RS-232 Optional Replaced by SBE 39plus in 2014
SBE 39-IM Temperature (P) Recorder T, P*   32 Mb   Inductive modem  
SBE 56 Temperature Logger T   64 Mb   USB    
SBE 26plus Seagauge Wave & Tide Recorder T, P C optional 32 Mb RS-232
(tides, waves, & wave statistics)
Wave & tide recorder
SBE 26 Seagauge Wave & Tide Recorder
T, P C optional 8 Mb RS-232   Replaced by SBE 26plus in 2004
SBE 53 BPR Bottom Pressure Recorder T, P C optional 32 Mb RS-232 Bottom pressure recorder
SBE 54 Tsunameter Tsunami Pressure Sensor T, P   128 Mb Optional RS-232 Tsunami pressure sensor
C = conductivity, T = temperature, P = pressure, DO = dissolved oxygen
* = optional
products are no longer in production. Follow the links above to the product page to retrieve manuals and application notes for these older products.

Elsewhere on this page: Profiling CTDs | Water SamplersInductive Modem Instruments | Shipboard Salinographs | Oxygen Sensors | pH Sensors | Other Products

 

Inductive Modem Instruments

SBE Measures
(C, T, P)
Auxiliary Sensors Memory Power Comments
Internal External
SBE 16plus-IM V2 SeaCAT C-T (P) Recorder C, T, P* 6 A/D; 1 RS-232 64 Mb   Optional pump
SBE 16plus-IM SeaCAT C-T (P) Recorder
C, T, P* 4 A/D; optional RS-232 or PAR 8 Mb   Replaced by SBE 16plus-IM V2 in 2008
SBE 37-IM MicroCAT C-T (P) Recorder C, T, P*   8 Mb    
SBE 37-IMP MicroCAT C-T (P) Recorder C, T, P*   8 Mb   Integral pump
SBE 37-IMP-IDO MicroCAT C-T-DO (P) Recorder C, T, P* Integrated DO 8 Mb   Integral pump
SBE 37-IMP-ODO MicroCAT C-T-DO (P) Recorder C, T, P* Integrated Optical DO 8 Mb   Integral pump
SBE 39-IM Temperature (P) Recorder T, P*   32 Mb    
SBE 44 Underwater Inductive Modem (UIM)   1 RS-232 30 Kb buffer Integrates sensor with standard serial interface (current meter, Doppler profiler, etc.) to inductive modem telemetry system
Underwater Inductive Modem Module (UIMM)   1 RS-232 16 Kb Sample Data Memory   Integrates sensor with standard serial interface (current meter, Doppler profiler, etc.) to inductive modem telemetry system; more flexible and economical than SBE 44

C = conductivity, T = temperature, P = pressure, DO = dissolved oxygen
* = optional

Notes:
1. See Inductive Modem Module (IMM) or Surface Inductive Modem (SIM), and Inductive Cable Coupler (ICC) to complete your inductive modem system.
2. See Application Note 92: Real-Time Oceanography with Inductive Moorings and the Inductive Modem Module (IMM) for background information.
3. products are no longer in production. Follow the links above to the product page to retrieve manuals and application notes for these older products.

Elsewhere on this page: Profiling CTDs | Water Samplers | Moored Instruments | Shipboard Salinographs | Oxygen Sensors | pH Sensors | Other Products

 

Shipboard Thermosalinographs (Conductivity & Temperature)

SBE Measures Auxiliary
A/D Sensors
Recommended
Flow Rate
(cc/sec)
Remote Temperature
Sensor Input
NMEA
Data Input
Memory Power Communication Real-Time Data
Internal External
SBE 21 SeaCAT Thermosalinograph T, C 4 1000 64 Mb    RS-232
SBE 45 MicroTSG Thermosalinograph T, C   10-30 * *     RS-232
C = conductivity, T = temperature
* With optional PN 90402 SBE 45 Power, Navigation, and Remote Temperature Interface Box

Elsewhere on this page: Profiling CTDs | Water Samplers | Moored Instruments | Inductive Modem Instruments | Oxygen Sensors | pH Sensors | Other Products

 

Oxygen Sensors

SBE Sensor Type Output Depth (m) User-
Programmable?
Can be
Integrated with
Use
SBE 43 Dissolved Oxygen Sensor membrane 0 - 5 volts 600, 7000   Moored CTDs
(with 1.0-mil membrane),
or
Profiling CTDs
(with 0.5-mil membrane)
SBE 43F Dissolved Oxygen Sensor membrane frequency 600, 7000   Moored CTDs
(with 1.0-mil membrane),
or
Profiling CTDs
(with 0.5-mil membrane)
SBE 63 Optical Dissolved Oxygen (DO) Sensor optical RS-232 600, 2000, 7000 Moored CTDs or Slow Profiling CTDs
** Products are no longer in production. Follow the links above to the product page to retrieve manuals and application notes for these older products.

Elsewhere on this page: Profiling CTDs | Water Samplers | Moored Instruments | Inductive Modem Instruments | Shipboard Salinographs | pH Sensors | Other Products

 

pH Sensors

SBE Sensor Type Output Depth (m) Can be
Integrated with
Use
SBE 18 pH Sensor Electrode 0 - 5 volts 1200  
SBE 27 pH/O.R.P. Sensor Electrode 0 - 5 volts 1200 Includes O.R.P.
SeaFET ISFET RS-232 varies Satlantic product
** Products are no longer in production. Follow the links above to the product page to retrieve manuals and application notes for these older products.

Elsewhere on this page: Profiling CTDs | Water Samplers | Moored Instruments | Inductive Modem Instruments | Shipboard Salinographs | Oxygen Sensors | Other Products

 

Other Products

Sea-Bird Electronics manufactures many other products, including:

Catgegory Products
Autonomous profiling floats
(click here for a comparison of these floats)
Data Loggers and Counters
CTD Surface Power and Data Telemetry Systems
Modular Sensor and Components (conductivity, temperature, pressure, pH, and ORP sensors; and pumps

Elsewhere on this page: Profiling CTDs | Water Samplers | Moored Instruments | Inductive Modem Instruments | Shipboard Salinographs | Oxygen Sensors | pH Sensors

 

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