32
DSM300 Installation Manual
• On a boat with a fiberglass hull, the leading edge of the transducer should
extend 1/8" (3.2 mm) to 1/4" (6 mm) below the bottom edge of the hull as
shown in Figure 2-5 . On an aluminum hull, the transducer should extend a bit
more – 1/4" (6 mm) to 3/8" (9 mm)
• If the boat will be trailered, be sure the transducer will not hit any rollers,
bunks or fittings on the trailer.
Figure 2-5: Transom Mount Transducer - Vertical Position
Thru-hull Transducer and In-hull Transducer
Similar consideration should be given to the location of thru-hull and in-hull
transducers. Figure 2-6 shows the best transducer location for different hull types.
• Displacement hull powerboat – Locate at 1/3 aft load waterline length (LWL)
and 6 - 12" (150-300 mm) off the centerline on the side of the hull where the
propeller is moving downward.
• Planing hull powerboat – Mount well aft, on or near the centerline, and well
inboard of the first set of lifting strakes to ensure that it is in contact with the
water at high speeds. Mount on the side of the hull where the propeller is
moving downward.
No!
No!
No!
Average transom angle -
no wedge necessary
Vertical transom -
place wedge this way
Sloping transom -
place wedge this way
2° to 5°
2° to 5°
For fibreglass hull 1/8 to 1/4 in (3.2 to 6 mm)
For aluminium hull 1/4 to 3/8 in (6 to 9 mm)
The bow of the transducer
is above the bottom of the
transom, creating cavitation.
Rivets on the hull are
creating bubbles. Lower
the transducer a bit.
The rear of the transducer
is too high, creating
cavitation.
D4873-2
2° to 5°
