Facilities

120 Foot Towing Tank

Ship models up to about six feet in length can be tested for resistance and seakeeping properties. The dual-flap wave-maker at the end of the tank is similar to the wave-maker in the 380 FT Towing Tank, so wave-making techniques can be developed here and then reproduced in the larger facility. The tank is setup for normal, powered carriage towing (constant velocity), as well as gravity-powered towing (constant force). Measurement signals from the carriage are wired directly to shore using a shielded cable carrier system.  The data acquisition systems on shore are interchangeable with those used in the 380 FT Towing Tank.  The smaller tank size allows for shorter delays between runs, and the tank can be drained quickly for shallow-water testing.

Length = 120 FT (37.0 m)
Breadth = 8 FT (2.4 m)
Depth of Water = 0 FT to 5 FT (1.5 m)
Carriage Travel = 85 FT (26.0 m)

DESCRIPTION OF CARRIAGE:

Unmanned, overhead monorail with side rail for roll stabilization.

TYPE OF DRIVE SYSTEM AND TOTAL POWER:

Wire-tow cable driven by electric motor, 7 HP (5.2 kW); computer-controlled using touchscreen.

WAVE GENERATION CAPABILITY:

Regular, irregular, and transient water waves; wave frequency range 0.25 Hz to 1.40 Hz.

WAVE-MAKER TYPE AND EXTENT:

Dual-flap, servo-hydraulic control with dry back.

BEACH TYPE AND LENGTH:

7 layers of 0.5 IN (13 mm) square tubes, 16 FT long (4.9 m), nominal slope of 1:3.

INSTRUMENTATION:

Identical to equipment used in 380 FT Towing Tank.

TESTS PERFORMED:

Resistance; self-propulsion; seakeeping; shallow-water; various tests of fixed and moored ocean structures; hydrodynamic forces on submerged bodies, foils, etc.; capsize tests; flow visualization; and basic ocean wave mechanics.

OTHER REMARKS:

Side windows in tank; gravity-tow capability; shallow-water tests (calm water only); short delay between runs.