When sound emitted from the sonar hits a submerged target of any height above the seabed, an acoustic shadow is produced from the sonar. An experienced sonar operator can use the length of these shadows to get an idea of the size and height of the object.

To help you understand this, imagine that you are in a dark room, holding a flashlight and standing above an object. If you shine the light down on the object, a small shadow is cast around it, while if you lie down at the same level as the object and shine the light at it, a much longer shadow is produced stretching away from it. 

What’s under your boat? If you want to understand how your sonar works, just click on the following link and allow yourself to be taught with utmost care and proper guidance.

INTERPRET what you see.

MAXIMIZE your fishing.

Vassilis is a passionate and knowledgable freediving and spearfishing trainer.