36
DSM300 Installation Manual
Figure 2-8: Position of Screws in Mounting Bracket
Installation
1. On a fiberglass hull, to minimize surface cracking of the gel coat: Before drill-
ing the pilot holes, use a 1/4" (6 mm) drill bit to drill a shallow hole (chamfer)
at each location about 1/16" (1.5 mm) deep.
Drill pilot holes 3/4" (19 mm) deep using a 9/64" (3.6 mm) drill bit.
To prevent drilling too deeply, wrap masking tape around the drill bit about
7/8" (22 mm) from the tip. Drill in only as far as the tape.
2. Apply a good quality marine sealant to the pilot holes to protect the hull from
water penetration.
3. Attach the bracket to the hull using the panhead screws with flat washers. Do
not completely tighten the screws yet.
4. Move the bracket up or down so the leading edge of the transducer has the
clearance shown in Figure 2-5 .
5. Once the bracket is in the correct position tighten the screws.
2.5 Installing the Thru-hull Transducer
Tools and Material Needed
Water-based antifouling paint (mandatory for boats kept in salt water)
Safety goggles
Dust mask
Electric drill
Drill bit: 1/8" (3 mm)
D4875-2
Insert screws 1 and 3, 6.4 mm (1/4 in)
from the bottom of the slots, and
screw 2, 6.4 mm (1/4 in) from the top
the slot to allow room for adjustment.
If screws are inserted this way it
won't be possible to make the
height adjustment.
1
Correct alignment
Incorrect alignment
2 3
1 2 3
