tenndave,
Welcome to the forum. What type of boat do you have? This is a very common problem with the SI transducers.
Post some pictures of your transducer installation. Straight on from the rear and from the side. You may need to drop it down just a little.
Many guys have gone to using a shoot thru hull transducer and Y cable for better 2d readings at high speed.
Good Luck,
Robert