Facilities

380 Foot Towing Tank

This tank is equipped with two towing carriages, a dual-flap wave-maker, and a wave-absorbing beach.  The smaller carriage is lighter and capable of towing small models at higher speeds.  The larger carriage is heavier and used to tow large models at lower speeds.  Both carriages are set up with platforms to carry ten or more students, allowing close-up observation of the underway test subject/model.  The center section of the tank’s beach can be lowered to allow access to a finger pier for ballasting and setting up experiments while the tank is being used for other tests.  Measurements from sensors on towed models are monitored and recorded using an onboard computer.   Digital measurement records and live HD video signals are transferred to the shore-based control room using wireless networks.  Measurement records can be evaluated/analyzed onboard the carriage and in the control room.

This tank has been used to test a wide variety of models, including: ships, submarines, planing hulls, hydrofoils, surface-effect craft, SWATHs, sailboats, offshore platforms, wave buoys, diving systems, mine arrays, pilings, etc.  The tank has also been used to study wave motions and forces, without the use of models.

Length = 380 FT (116.0 m)
Breadth = 26 FT (7.9 m)
Depth of Water = 16 FT (4.9 m) 
Carriage Travel = 270 FT (82.0 m)

DESCRIPTION OF CARRIAGE:

1) High-Speed – 11,000 LB box girder, steel wheels, round rails; maximum speed 32 FT/S (9.8 m/s).

2) Low-Speed – 22,000 LB box girder; maximum speed 25 FT/S (7.6 m/s).

TYPE OF DRIVE SYSTEM AND TOTAL POWER:

Shore-mounted motors with twin tow cables; two motors @ 200 HP (150 kW) with 400% overload capability; controlled from shore using a computer-driven touchscreen.

OTHER CAPABILITIES:

Large and small horizontal planar motion mechanisms (PMMs).

Open-water propeller testing.

Current-driven turbine testing.

WAVE GENERATION CAPABILITY:

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

WAVE-MAKER TYPE:

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

BEACH TYPE AND LENGTH:

Four layers of 2 IN (5 cm) square tubes, 60 FT long (18 m); nominal slope of 1:5.

INSTRUMENTATION:

Sensors and amplifiers for measuring: force, moment, distance, angle, rotation rate and position, velocity, acceleration, inertial motion, wave elevation, water particle motion, pressure; multiple 16-bit analog-to-digital, USB-based data collection systems with sample rates of 20KHz+.

TESTS PERFORMED:

Resistance; self-propulsion; seakeeping; open-water propeller; horizontal planar motion; various tests of fixed and moored ocean structures; hydrodynamic forces on submerged bodies, foils, etc.; capsize and dynamic stability tests; flow visualization; basic ocean wave mechanics; etc.