KULAÇ, an echo sounder system developed indigenously by Turkey's leading defense electronic systems producer, ASELSAN, and used in Turkish submarines, has been put into action for the first time abroad by Indonesia.Turkey's first export regarding underwater acoustic systems, ASELSAN's KULAÇ Echosounder System has been integrated into an Indonesian submarine.Integration and approval projects conducted in the KRI Nanggala 402 submarine included in the Indonesian Navy's inventory were completed within a short period of time. It is expected that the Indonesian Navy's demands for ASELSAN-made submarine and underwater acoustic systems will increase following the system's successful activation.KULAÇ helps submarines and vessels sail safely as the system precisely informs the user about the depths of the ships and submarines by measuring the distance by receiving the echoes from transmitted by acoustic signals and measuring the time difference between the sent/received signals.The KULAÇ Echosounder is composed of a transmitter, receiver and processor unit, remote display unit and low-high frequency acoustic transducers. Operating with high precision, the system can measure down to 1,000 meters. Along with its high-capacity recording option, it enables the simultaneous usage of more than one acoustic system in one platform.The Turkish-built echo sounder system has three range determination modes: Auto-Interval, Auto-Phase and Manual. When "Auto-Interval" or "Auto Phase" range determination mode is selected, pulse power and pulse length of transmissions are automatically adjusted by the system.The system is capable of data recording, transferring data to external storage via USB and printing recorded and instantaneous measurements.KULAÇ has the capability to self-test in addition to a built-in test infrastructure which can inform the user about the source of the problem when an error occurs.The system developed by ASELSAN was integrated into submarines included in the Turkish Naval Forces inventory. Operating uneventfully since 2013, KULAÇ will be used in ADA Class Corvettes (MİLGEM) and multipurpose Amphibious Assault Ships (LHD) in the coming period.