[CA] can you tell what this black thing is?

[Chuck - Raymarine - Moderator]

Ray18,

Objects having vertical height above the bottom will cast sonar shadow. As an object's height above the bottom increases, so will the size of its sonar shadow. Best SideVision and DownVision image is accomplished when the vessel maintains a relatively constant speed 3-5 MPH with little roll. When trying to identify an object it often helpful to pass the object from different directions. As with all sonar imaging, experience gained through use of the product combined with knowledge of the underwater structures will over time permit you to increase your ability to identify underwater objects.