The lower step is the only part of the hull in the water on plane ...
Mount the xducer on the upper step at least far enough to the side that the motor doesn't hit it at full lock to that side ...
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Then if you need high speed depth readings you will need a shoot thru XP 9 20 epoxied in the hull and the 9 MSIDB Y cable ...
https://www.humminbird.com/productDe...id=728&id=1265
https://www.humminbird.com/Products/9-M-SIDB-Y/
Rickie