Ice tank

Description of tank:

Rectangular tank 90 m (295.28 ft) in length, 12 m (39.37 ft) in width and 3 m (9.84 ft) in depth, models are towed, self-propelled or moored in a simulated Arctic environment. A thermal barrier door separates set up area from active freezing test portion of tank.

Description of tow carriage:

Manned carriage with a 4 wheel or rack synchronous motor drive, test frame adjustable for model size, 80,000 kg mass, 745 kW of power for a drive force of 60 kN, speed range of 0.0002 m/s to 4.0 m/s.

Description of service carriage:

Separate carriage with adjustable height work platform and rotatable push blades for ice management and ice ridge construction. Carriage is independently controlled or can be connected to tow carriage.

Refrigeration:

Ammonia-based system, 26 evaporators, computerized control, temp. range –30°C to +15°C, ice growth 2.5 mm/hr @ -20°C.

Test ice:

NRC EG/AD/S formulation; fine grain columnar structure with controllable density to correctly model ice buoyancy; thickness range 5 mm to 160 mm (thicker on occasion), ice strength range 10 kPa to 150 kPa.

Model size:

Ship models 2 – 12 m in length, offshore structures 0.5 – 4 m in diameter.

Instrumentation:

Force measurement, strain gauge load cells, model displacement and motions, accelerometer arrays.

Data acquisition:

VMS and Windows NT Client/Server System with NEFF and in-house designed signal conditioning. 256 channel capability with data rates up to 100 kHz, 16 bit resolution.

Specialized instrumentation:

  • Video cameras mounted on an underwater carriage and also above the water line.
  • DART (Digital Acoustic Radar Transceiver) mounted on underwater carriage for accurate ice rubble and ice ridge thickness profiles, and for measuring ice build up in front of structures.
  • Large amplitude (± 4 m) PMM (Planar Motion Mechanism) for measuring manoeuvring performance of vessels in ice or open water and for simulating changes in ice drift heading on fixed structures.

Tests performed:

  • Ship resistance and self-propulsion ice and open water.
  • Ice forces on moored and fixed structures
  • Offshore simulation
  • Captive and free manoeuvring in ice