Simrad EQ60 - Manual (Page 189)

Transducer installation
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857-164342 / Rev.C
Ways of mounting the transducer
Inclination of the transducer face
Incline the transducer face approximately 3 degrees, so that the
flowing water meets it directly. This assures laminar water flow.
Mounting screws should not be extruding from the transducer,
and the space around the screws could be filled with a
compound or a locking ring.