Scientific Equipment

CTD Systems

Sikuliaq sails with a SeaBird 911+,  dual conductivity and dual temperature sensors in a standard SeaBird Carousel with 24-12 liter Niskin bottles. The Niskin bottles have internal teflon coated springs and dual sampling petcocks, one for standard use (1/4" I.D.tubing) and one for larger volume sampling (1/2" I.D. tubing).  All niskin bottle O-rings are non-toxic silicone (red/orange type).  A complete spare system (911+, sensors, niskins bottles, rosette frame) is on board.
Sensors typically attached are:

• SBE 43, Dissolved oxygen - 7000m

• Wet Labs FL or ECO Fluorometer - 6000m (please inquire about wavelength)

  • FLRTD/FLCDRTD

  • FLNTURTD

  • ECO Triplet - 600m

    • The ECO Triplet is configured to measure Chlorophyll, FDOM and Scattering @ 650nm.

    • Note: The ECO Triplet is connected via the SBE 911+ serial uplink port. The data output is not integrated with the 911+ system, but logged separately into our data system. A merged file, with core CTD data appended to it, is also logged.

• WetLabs C-Star 25cm Transmissometer - 6000m

• Biospherical QSP-2300 PAR - 2000m

• TriTech PA200/20 Altimeter - 6000m

Additional sensors available upon request:

• SBE 18, pH - 1200m

• RINKO III Oxygen Optode - 7000m

All three of Sikuliaq's SBE 911+ units have the serial uplink option. The maximum allowable current draw for all frequency and auxiliary voltage sensors is 1 amp. Sensors supplied by the science party can be integrated and mounted to the CTD instrument cage or rosette frame. Please provide advanced notice by contacting the Science Operations Manager.

Additional CTD systems available upon request:

• SBE 49 FastCAT with PDIM and SBE 33 deck unit

• CastAway

• Star-Oddi DST Centi-TD - Miniature Temperature and Depth Data Logger

Scientific Navigation and Timing

SeaPath 380-R3 Precise Heading, Attitude and Positioning Sensor

Seapath is Sikuliaq's primary inertial navigation system for scientific applications. Two unobstructed GNSS receivers on top of the main mast (2.5 meter spacing) determine position and velocity. A MGC-R3 unit, which is a combined motion sensor/gyro compass, measures heading, roll, pitch, and heave. The C-NAV3050 differential correction improves the Seapath's accuracy to within less than one meter. The position is referenced to the origin of Sikuliaq's 3-D coordinate system, which is a granite block located in the Science Hold. Seapath provides 100 Hz navigation and timing information to all of the Kongsberg hydrographic systems (EM304, EM710, TOPAS PS18, EK80). The ship's science data acquisition system records this at 1 and 10 Hz, and provides various types of data broadcasts distributed throughout the ship.

• Specifications Sheet

C-NAVX1 GCDGPS Receiver

• Specifications Sheet

Trimble MPS865 Modular GNSS Heading Receiver

• Specifications Sheet

Tekron NTS-03-G+ Time Server

• Specifications Sheet

Science Echosounder Systems

Sikuliaq has one of the most advanced suites of hull-mounted acoustic sensing systems in the US academic research fleet. Due to its ice-clearing hull shape, the transducer arrays are installed on a sonar flat - referred to as a blister - and retractable drop keel - referred to as a centerboard. The start of the blister transitions from the bottom of the vessel's ice knife at the bow, with the EM304 MKII Tx array. All of the transducer wells in the blister are flooded with seawater and protected by acoustically-transparent ice windows, except for the EM710 which is encapsulated in titanium. See the diagram below for spare well locations.

In 2016, the two Ocean Surveyor ADCPs were relocated from the fwd outboard wells to the aft inboard spare wells in order to reduce the effects of bubble sweep. More detail on the centerboard transducer arrangement can be found below.

In 2022, the fleet spare OS38 was installed for a trial evaluation.

All of the vessel's transducer arrays have been surveyed into Sikuliaq's 3-D coordinate system with a distance precision of <5mm and angular precision of <1 arc minute. Multi-beam patch tests and EK80 target strength calibrations are performed annually. Impedance measurements are made annually for each element of the EM710 and EK80 arrays. EM304 impedance is automatically measured when BIST tests are conducted, usually at the start of each cruise.

Transceiver Units (TRUs) for the EM304, EM710, and TOPAS are located in the Electrician's Workshop on the 1st Platform. The EK80 wide-band transceivers (WBTs) are located in the Main Lab, and the ADCP transceiver deck units are located in the Computer Lab. All of the operator workstations are in the Computer Lab. K-sync can provide external triggers to all of the scientific echosounders - but not the bridge navigation equipment - to help reduce acoustic interference between systems. Realtime spectrograms from the HAP-5050 hydrophone array are useful for self-noise monitoring. Sikuliaq meets strict requirements for minimizing Underwater Radiated Noise (URN).

• Sonar Flat

• Sikuliaq Sound Source Matrix

• Underwater Sound from Research Vessels

• Kongsberg K-sync Synchronizing Unit

  • Mitigating Echosounder Interference with K-Sync

• Knudsen 3260 12 kHz - Chirp PDR

• Teledyne Benthos Universal Deck Box  - located in the aft LAN rack in the Main Lab

  • Airmar 12 kHz through-hull transducer

  • Tonpilz 4 - 24 kHz transducer - mounted to the bottom of the centerboard

    1. Specs

  • The science party can attach their own acoustic deck box to the ship's centerboard transducer or hull-mounted transducer via a  BNC cable connection, in the Main Lab.

• HAP 5050 - Self Noise Monitoring Array

  • Hydrophone Array Layout

    1. Note: the hydrophone coordinates are based on the 2016 ship coordinate survey.  The hydrophones were not surveyed during the 2024 coordinate survey.

  • A/D specs

• LSE 297 50 kHz - Bridge Navigation Sonar

• LSE 297 200 kHz- Bridge Navigation Sonar

• Sperry Doppler Speed Log

300 kHz ADCP

A Teledyne RDI Workhorse Sentinel 300kHz ADCP, with an integrated pressure sensor, is installed in the forward spare well on the Centerboard. There is no ice-window or deck unit installed. Data acquisition is via UHDAS. If the science party requests use of the spare well, this ADCP will be temporarily removed.

UHDAS Daily Current Figures available when the ship is underway and running the ADCP.

38 and 75 kHz ADCP

Sikuliaq has three ADCP transducers mounted on the hull. See the Acoustic Arrangement above for locations. Data acquisition is via UHDAS.

• Teledyne RDI Ocean Surveyor 38 kHz ADCP

• Teledyne RDI Ocean Surveyor 75 kHz ADCP

• Teledyne RDI Ocean Surveyor 150 kHz ADCP - installed but not working.

• Glass-filled, polycarbonate ice windows are used to protect the transducers.

• UHDAS Daily Current Figures available when the ship is underway and running the ADCPs.

Simrad EK80

• Five split-beam transducers: 18kHz, 38kHz, 70kHz, 120kHz, 200kHz

• The transducer array is located on the centerboard, which is either flush to the hull or lowered 8 ft (2.44m) below the hull

• Ice Window: No

• An electronic control system with three Cannon down-riggers is used for Target Strength calibrations.

• Transducer Datasheets

Kongsberg EM304 MKII Multi-beam

• Operating Freq: 20-30 kHz

• Transducer array: .5 deg X 1 deg

• Depth Range: 10m-Full Ocean Depth

• Pulse Forms: FM chirp

• Max soundings/ping: 1600

• Depth Resolution: 0.5 m

• Ice Window: Yes

• Datasheet

• 2024 Sea Acceptance/Calibration Report

• 2025 EM304 MKII Quality Assurance Testing 

Kongsberg EM710 Multi-beam

• Operating Freq: 70-100 kHz

• Transducer array: .5 degree X 1 degree

• Depth Range: 3-1000m

• Pulse Forms: CW and FM chirp

• Max soundings/ping: 400

• Depth Resolution: 1 cm

• Ice Window: Yes

• Datasheet

• 2025 EM710 Quality Assurance Testing 

Kongsberg TOPAS PS18 Parametric Sub-bottom Profiler

• Frequency Range: 0.5-6,15-20,30-42kHz

• Signatures : CW, Chirp, Ricker

• Depth Range: 30 – 10000m

• Max Penetration: ~150m

• Audible noise inside hull: none

• Ice window: Yes

• Datasheet

Centerboard

Sikuliaq is provisioned with an acoustic drop keel (Centerboard). It can be lowered/deployed 8 feet (2.44m) below the hull where its transducers are out of the bubble sweep boundary layer.

• There is a spare 12" well where the Workhorse 300 ADCP normally resides. Other installations have included a USBL, LBL, and camera.

• The transducer array can be accessed while the ship is in the water when the centerboard is raised into a maintenance position. It can also be placed flush with the hull or recessed two feet into the hull for protection from sea-ice.

• When the WH300 ADCP is running, its pressure sensor can indicate the postion of the centerboard acoustic array:

  • Deployed, 8.2 meters below average water line

  • Flush with Hull, 6.0 meters below average water line

  • Note: When the centerboard is in the Safe position, recessed 2 ft (0.5m), the WH300 will not be run.

• A Sea-bird SBE 38 temperature sensor and AML Sound Velocity sensor are installed at the bottom(shoe) of the centerboard.

• Slotted gratings have been installed on opposite sides of the centerboard shoe to increase the re-fresh rate of sea-water.

• A Pump at the bottom(shoe) of the centerboard can provide water for the Uncontaminated Seawater System when the bow intake is clogged with slush/ice.

Sikuliaq Centerboard Arrangement
Sikuliaq Acoustic Arrangement

Rutter X-Band Radar

The primary interface for this system is located on the bridge while remote viewing is accessible through the ship's video distribution system. An interactive website is also available via Sikuliaq's ship-side website.

The CSTARS radar processing generates near-real time wave, near-surface current, sea surface roughness, and sea ice drift products. It is based on the raw backscatter intensity measurements of a Sperry Marine BridgeMaster E marine X-band radar, which are acquired by Rutter’s Ice Navigator in the binary SIG format. To ensure high quality results, the radar is regularly calibrated for azimuth, range, and time offsets and the processing is continuously monitored. The products are stored in NetCDF format and include two-dimensional (2D) wave energy density spectra and the associated peak and mean wave parameters, 2D gridded near-surface current measurements, mean sea surface roughness and sea ice image mosaics with a 10 min update rate, and 2D gridded sea ice drift measurements. All products will be included in the underway data archive. 

Mean sea surface roughness and sea ice images with a 30 s update rate can be included upon request. The SIG files are stored on a shipboard NAS server that is regularly swapped and shipped to CSTARS for post processing (if necessary) and archival. For lack of computational resources, concurrent sea ice drift and current mapping are not yet possible, but can be performed post cruise at CSTARS.

• Sigma S6 WaMos II

• Sigma S6 Ice Navigator

• Scientific Uses

Sikuliaq has been provisioned with three Barnstead™ D4641 E-Pure™ Water Purification Systems. They are located in the Analytic Lab, Wet Lab, and Main Lab.

• Resistivity: 18-18.2MW-cm at 25°C

• Feed-water source: Distilled Water

• Data sheet

Uncontaminated Seawater System (UNCSW)

• Bow intake is located 6.0 meters below average waterline on the port-side of the ice knife, forward of the bow thruster intake. See photo below.

• Bypass line for a Sea-bird SBE 38 temperature sensor near the intake

• Hayward dual strainers with 1/32" mesh size on baskets

• Fybroc series 2530 close-coupled seal-less pump with variable speed motor

• Typical system pressure is 20 psi

• Insulated SeaCor thermoplastic 2" CPVC schedule 80 pipe & fittings

• Multiple, serial, 3/4" FNPT outlets in the Main Lab, Wet Lab, and Analytical Lab to plumb in instruments from your science project or for underway water sampling. One, 1" FNPT outlet, in the Baltic Room.

• Final discharge into the centerboard void

• Freshwater flush performed at the end of each cruise. Bleaching of pipes performed periodically (instruments are bypassed).

• Note: There is a warming effect between the sea-chest intake and the labs. This can be quantified by the temperature difference between the SBE 38(intake) and the SBE 45(Wet Wall) sensors.

• UNCSW System Arrangement

Sea-Ice Operations

If the bow intake becomes clogged/frozen with slush, seawater can be supplied to the Wet Wall, PCO2 system and main lab sinks via a pump system in the centerboard.

• When the WH300 ADCP is running, its pressure sensor can indicate the postion of the centerboard UNCSW pump:

  • Deployed, 8.2 meters below average water line

  • Flush with Hull, 6.0 meters below average water line

  • When the centerboard is recessed into the SAFE position(2 feet above the hull), intake depth is 5.5m below the average waterline. This is essentially the same water passing under the hull because water passes under the hull and into the void created.

Please contact the Science Operations Manager with any questions.

Incubator Seawater System

• Intake source is the same as UNCSW at 6.0 meters below waterline

• Water temperature data can be obtained from the Sea-bird SBE 38 instrument as part of the Uncontaminated Seawater system. See above.

• Carver GH series pump

• Typical system pressure is 30-50 psi

• Copper-nickel 3" pipe and fittings

• Outlets: main deck aft of Baltic Room, 01 foredeck and 04 deck aft of bridge

• Deck manifold available upon request

• Final discharge is out of the incubators and over the side of the ship

• Incubator Seawater System Arrangement