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Towing Tanks

INSEAN has two towing tanks. Tank no. 1 is today one of the largest worldwide. It is 470 m long, 13.5 m wide and has a depth of 6.5 m. It is equipped with a towing carriage that can achieve a maximum speed of 15 m/s.
Tank no. 2 is of smaller size (220 m 9 m 3.8 m) and maximum carriage speed of 10 m/s. It is equipped with a single-flap wave generator, that provides regular as well as irregular waves for the investigation of seakeeping characteristics and ride comfort.

 

Carriages of Towing Tank n. 1 (right) and n. 2 (left)Carriages of Towing Tank n. 1 (right) and n. 2 (left)

 

The towing tanks have many applications, mainly concerning resistance and propulsion tests for performance evaluation of proposed design. The size of towing tank no. 1 offers excellent capabilities for the investigation of large, self-propelled models of high-speed vessels (mono- or multi-hull, semi-planing and planing craft, etc.) Equipments and methodologies for testing submarines and sail boats are available. Various unconventional marine vehicles are also designed and tested.

 

Tank no. 1

Description of tank:  length = 470 m, breadth = 13.5 m, water depth = 6.5 m

Description of carriage: motor driven, manual control and automatic, manned

Drive system and power: Electric drive system with 4 pairs of drive wheels, each pair coupled to a DC main motor via a reduction gear. Electric main motors (92 kW × 4), electric secondary motors (5.5 kW × 2)

Maximum carriage speed: 15.0 m/s (accuracy 1 mm/s)

Other capabilities: the carriage supports the set up of the 6-component balance for submerged bodies or the vertical and horizontal Planar Motion Mechanism (PMM) for surface ships and submarines tests up to 5 m/s

Instrumentation: Force balance dynamometers; model propeller transmission dynamometers; Pitot tube rakes and five-hole Pitot tube for wake surveys; capacitive transducers for wave cut experiments. Special test rig for sailing yacht tests; 6-component balance and model propeller transmission dynamometers for manoeuvring tests (PMM), LDV 2-D measurement system  

Model size range: 1.5 m÷8.0 m  

Tests performed:

(1) Resistance and self propulsion in calm water
(2) 3-D wake surveys
(3) Vertical and horizontal planar motion experiments
(4) Resistance, self propulsion and hydrodynamic forces on submerged bodies
(5) Resistance, self propulsion tests at high speed on High Speed Marine Vehicles
(6) Upright, yawed and heeled sailing yacht tests
(7) Longitudinal wave cut experiments

 

 

Tank no. 2

Description of tank:   length = 220 m, breadth = 9.0 m, water depth = 3.5 m

Description of carriage: motor driven, manual control and automatic, manned  

Drive system and power: Electric drive system with 8 drive wheels, each coupled to a DC main motor via a reduction gear, and 2 pairs of horizontal guide wheels (only on one rail). Electric main motors (57 kW × 8)

Maximum carriage speed: 10.0 m/s (accuracy better than ±0.15 %)  

Wave generation capability: regular waves from 1 to 10 m in length, with corresponding height of 100 to 450 mm (slope 1°÷9°); irregular waves according to any desired sea spectrum condition in appropriate scale  

Wavemaker type and extent: one-side flap-type, 9 m wide, electro-hydraulically powered with 3 pumps of 38.5 kW total power, controlled by a 100 harmonic components electronic programming device, each harmonic modulated both in amplitude and frequency  

Beach type and length: 2 crossed layers of square tubular 70 × 70 mm equally spaced, with movable central part for model transit  

Wind generation capability: for mooring tests an additional structure, carrying wind generators, can be added on the beach of the carriage and oriented on the horizontal plane; air blowing generation system, of 2 rows with 6 fans each, capable of a continuous variation of speed (from 0 to 20 m/s), direction (0°±20°) and vertical gradient

Instrumentation: force balance dynamometers; model propeller transmission dynamometers; 5-holes Pitot tube rakes for wake surveys; 1 to 6-component balance for rudders and ship models tests; fully submerged propeller dynamometer (thrust range = ± 400 N, torque range = ± 15 Nm, speed range = 60 to 3000, rpm motor power 5 kW, right and left hand rotation, inclined operation up to ±15° in vertical plane) for open water characterisation of propellers in axial or inclined flow; 3-D optical system and inertial platform for measuring ship model motions in waves

Model size range: 1.5 m÷8.0 m  

Tests performed:

(1) Resistance and self propulsion in calm water (in deep and shallow water)
(2) 3-D wake surveys
(3) Open water propeller characterisation
(4) Seakeeping and propulsion evaluation in head and following waves
(5) Hydrodynamic forces on profiles, especially of rudders and medium and large sized ship models
(6) Mooring tests