[CA] Strange black square in 3d sonar images from Axiom 9"?

[Chuck - Raymarine - Moderator]

Welcome back to the Raymarine Forum Ray18,

The black box is indicating missing data possibly due to something passing very close beneath the transducer, aeration of the transducer possibly caused by backing down the engine(s), etc. Should you pass over the area again, then I would expect that the area previously occupied by the black box to fill in.