// 3/16 inch in mm deck_depth = 4.7625;
// 1/4 inch in mm = 6.35
// subtract a little to be a squeeze fit
-deck_depth = 6.35 - 0.4;
+deck_depth = 4.7625 - 0.4;
sonar_plate_width = 20;
// sonar sensor measurements taken with calipers:
// 10.82 in between, 42.33 outside, 15.82 diameter