if constantly you are having slanted arches in the same direction then you possibly have to level your transducer. BUT in many cases slanted arches are just fish that are on the edge of the cone angle. If they are all angled the same way all the fish could just be on one side of the boat and not under you or on the other side. This screen shot is an example. 95% of the arches are slanted and one way with a few and the large bait ball slanted the opposite. Very few fish in this screen shot were directly fully in the cone angle. The transducer is also a very expensive Airmar with self leveling capabilities and just a few hundred feet down the lake I was once
again getting perfect arches.
Hope that helps...Ryan
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