Raymarine DS400 & DS500 User Manual

Chapter 2: Installation

19

1. At the selected location on the starboard side of the hull, position the 

transducer, so the transducer projects 3mm (1/8") below the bottom edge 
of the transom (see Figure 2-10 ). 

2. Being sure the bottom of the transducer is parallel to the waterline, mark 

the location of the screw holes with an “X” in the center of the two outer 
most slots.

3. Using a 4mm, #23, or 9/64" drill bit, drill two holes 22mm (7/8") deep at 

the locations indicated. To prevent drilling too deeply, wrap masking tape 
around the bit 22mm (7/8") from the point.
Fiberglass hull—Minimize surface cracking by chamfering the gelcoat. 
If a chamfer bit or countersink bit is not available, start drilling with a 
6mm or 1/4" bit to a depth of 1mm (1/16").

•

Standard transom (13° transom angle)—The bracket is designed for a 
standard 13° transom angle. The shim is not needed for this installation. 
Skip to Mounting the Bracket.

•

Stepped transom and jet boats (3° transom angle) —Use the shim with 
the tapered end down. Be sure the nuts are in the slots in the back of the 
bracket before applying the shim (see Figure 2-8 ).

•

Small aluminum and fiberglass boats (20° transom angle)—Use the 
shim with the tapered end up. Be sure the nuts are in the slots in the back 
of the bracket before applying the shim (see Figure 2-8 ).

•

If you are unsure about using the shim, do one of the following:

•

Measure the transom angle of your boat using a digital level or bubble 
level and protractor. Then follow the instructions above for your tran-
som angle.

•

Experiment with the shim by following the instructions Mounting 
the Bracket and Checking the Angle and Projection.

1.  Apply marine sealant to the threads of two, #10 x 1-3/4", self-tapping 

bracket screws to prevent water seepage into the transom.

2. Screw the transducer (with the shim if needed) to the hull (see Figure 2-10 

). Do not tighten the screws at this time.