These imaging sonars transmit sound pulses and convert the returning echoes into digital images, much like a medical ultrasound sonogram. The advantage is that they can “see” what’s going on through dark or turbid (cloudy) water in zero visibility conditions. With 128 beams operating at 3MHz, the ARIS Explorer 3000 collects more data than many others. Its depth rating is 300m. For longer-range applications, there are the Explorer 1800 and 1200 models.