ultrahelimeetodil põhinev mittepurustav katsetamine, mille korral muundur ja katsekeha, mis toimivad akustilise paarina, on sukeldatud veevanni (vt ultraheliuputuskatse), the inspection by ultrasound of engineering parts and components submerged in a tank of water, or water squirters must be used to act as couplant for ultrasonic beam (see: ultrasonic immersion test)