Installation Procedure - Furuno DFF1 Operator's Manual

1.3.3

Installation procedure

1. With the boat hauled out of the water, mark the location selected for mounting the
transducer on the bottom of the hull.
If the hull is not level within 15° in any direction, fairing blocks made out of teak
should be used between the transducer and hull, both inside and outside, to keep
the transducer face parallel with the water line. Fabricate the fairing block as
shown below and make the entire surface as smooth as possible to provide an
undisturbed flow of water around the transducer.
The fairing block should be smaller than the transducer itself to provide a channel
to divert turbulent water around the sides of the transducer rather than over its
face.
Upper
half
2. Drill a hole just large enough to pass the threaded stuffing tube of the transducer
through the hull, making sure it is drilled vertically.
3. Apply a sufficient amount of high quality caulking compound to the top surface of
the transducer, around the threads of the stuffing tube and inside the mounting
hole (and fairing blocks if used) to ensure watertight mounting.
4. Mount the transducer and fairing blocks and tighten the locking nuts. Be sure that
the transducer is properly oriented and its working face is parallel to the water line.
Fairing block
Hull
bottom
Note: Do not over-stress the stuffing tube and locking nuts through excessive tighten-
ing, since the wood block will swell when the boat is placed in the water. It is suggested
that the nut be tightened lightly at installation and retightened several days after the
boat has been launched.
Hole for
stuffing tube
Lower
half
Saw along slope of hull.
Construction of fairing block
Flat washer
Deep-V Hull
Rubber
washer
Flat Hull
5
BOW
Hull bottom