2. Select the Angle
Use a bevel gauge to confirm the angle of the V-hull at the mounting location, then choose the transducer tilt angle that most closely matches so that the sonar beam is transmitting as vertically as possible. The Airmar B175HW, for example, is available in three angles: zero tilt (for zero- to 7-degree deadrise), 12-degree tilt (for 8- to 15-degree V-hulls) and 20-degree tilt (for 16 to 24 degrees). Our V-hull has 22 degrees of deadrise, so we chose the 20-degree-tilt version.