Humminbird MHX XNT Installation Instructions Manual

High Speed Impact-Release Transom Mount Transducer

Installation Overview

Before you start the installation, we encourage you to read these instructions carefully in order to get the full
benefit from your Humminbird® accessory.
NOTE: Due to the wide variety of hulls, only general instructions are presented in this installation guide. Each
boat hull represents a unique set of requirements that should be evaluated prior to installation. It is important
to read the instructions completely and understand the mounting guidelines before beginning installation.
NOTE: Your transducer may not look exactly like the transducer shown in the illustrations, but it will mount
in exactly the same way.
Supplies: In addition to the hardware supplied with your transducer, you will need a powered hand drill and various
drill bits, various hand tools, including a ruler or straightedge, a level, a 12" plumb line (weighted string or monofilament
line), a marker or pencil, safety glasses and dust mask, marine-grade silicone sealant, and dielectric grease (optional).
You may also need extension cables and hardware for routing the cable to the control head.
Customer Service: If you find that any items are missing from your installation kit, visit our Web site at humminbird.com
or call Customer Service at 1-800-633-1468.

Installation

There are a number of ways to install a transducer on your boat. The transom mount installation provides the least
loss of signal since the transducer is mounted outside the boat hull. This installation also allows adjustment of
both running angle and depth after the transducer is mounted, which enables you to tune the installation for best
results. Also, the mounting hardware is designed to pivot the transducer body out of the way should the boat
strike debris in the water, or when trailering.
1.

Locating the Transducer Mounting Position

Turbulence: You must first determine the best location on the transom to install the transducer. It is very important
to locate the transducer in an area that is relatively free of turbulent water. Consider the following to find the best
location with the least amount of turbulence:
NOTE: Traveling over 65 mph with the transducer in the water is not recommended for the XNT 9 DB 74 T,
XNT 14 74 T, XNT 9 QB 90 T with the transom mount transducer, as damage might occur. If speed above
65 mph is critical, a different mounting technique (such as inside the hull) or another transducer type should be
considered. See the FAQ (Frequently Asked Questions) section of our Web site at humminbird.com.
• As the boat moves through the water, turbulence is generated by the weight of the boat and the thrust of
the propeller(s) - either clockwise or counterclockwise. This turbulent water is normally confined to areas
immediately aft of ribs, strakes, or rows of rivets on the bottom of the boat, and in the immediate area of the
propeller(s). Clockwise propellers create more turbulence on the port side. On outboard or inboard/outboard
boats, it is best to locate the transducer at least 15" to the side of the propeller(s).
• The best way to locate turbulence-free water is to view the transom while the boat is moving. This method
is recommended if maximum high-speed operation is a high priority. If this is not possible, select a location
on the transom where the hull forward of this location is smooth, flat, and free of protrusions or ribs.
• On boats with stepped hulls, it may be possible to mount the transducer on the step. Do not mount the
transducer on the transom behind a step to avoid popping the transducer out of the water at higher speeds.
The transducer must remain in the water for the control head to maintain the sonar signal.
• If the transom is behind the propeller(s), it may be impossible to find an area clear from turbulence, and a
different mounting technique or transducer type should be considered, such as an Inside the Hull Transducer.
• If you plan to trailer your boat, do not mount the transducer too close to trailer bunks or rollers to avoid
moving or damaging the transducer during loading and unloading of the boat.
• If high-speed operation is critical, you may want to consider using an Inside the Hull Transducer instead of
this Transom Mount Transducer.
531565-4_C

Transom Mounted Transducer

Areas of Possible Turbulence
rivets transom
strakes hull
Stepped Hull
step
Deadrise
deadrise angle
rib