User blog comment:SoSV/Subnautica Tips!/@comment-34764976-20180329115920/@comment-35129784-20180330221430

I've found that it does do something, but not that much. In my experiences leviathans have to get a bit closer to you before they find you, but given how they roam around it still seems inevitable they will find you eventually. It's certainly not going to render a 40m submarine invisible. You're better off just getting away if possible, using the defense shield if needed to mitigate their attacks. Once you move beyond a certain range they will give up.