There are two primary components to install with a typical fish finder, the control head and the transducer.

The control head contains the sonar transmit and receive circuitry, as well as the user controls and display. It should be installed in a location that provides access to the controls and visibility while in use. The control head usually mounts on a quick disconnect mounting system that swivels and tilts providing flexibility for viewing from almost anywhere on the boat. Some units come equipped for a permanent console mount.

The transducer converts electrical energy from the transmitter into mechanical pulses or sound waves. The transducer also receives the reflected sound waves and converts them back into electrical signals for display on the control head. It should be installed in contact with the surface of the water in an area that has smooth waterflow- usually on the transom of the boat. There are several mounting options for the transducr. The following section will help determine the method that works for you and your boat.

Determining How to Mount the Transducer
A standard transducer can be mounted on the transom of the boat, bonded to the inside of a many fiberglass hull boats or attached with a portable mount.

The transom installation, which is the most widely used, places the transducer on the outside of the boat hull. This technique produces the least signal loss, and provides a way to adjust the transducer after installation. The mounting hardware included is designed to protect both the boat and the transducer should the boat strike debris in the water or when trailering. The transducer must be placed in a location that has a smooth flow of water at all times. If the transducer is not placed in a smooth flow of water, interference will show on the sonar's display in the form of random lines or dots whenever the boat is moving. The transducer should be installed with it's face pointing straight down, if possible. Make certain the transducer's location doesn't interfere with the trailer or hauling of the boat. Also, don't mount it closer than approximately one foot from the engine's lower unit. This will prevent cavitation interference with the propeller. Typically, the transducer should be mounted as deep in the water as possible. This increases the chance that it will be in the water in high speed and reduces the possibility of air bubble interference.

As an alternative to transom mounting, it is possible on many fiberglass-hulled boats to glue the transducer on the inside of the boat hull. Since fiberglass has similar sonar characteristics as water, the sonar signal can pass through the boat hull with minimal loss. The hull of the boat must be single layer construction (not double-hulled) Also, any air trapped in the lamination of the fiberglass would prevent the sonar signal from passing through.
Inside the hull installations require no holes be drilled into the boat and through experimentation, high-speed operation comparable to transom mounting can be achieved. A two-part slow cure epoxy is usually required to glue the transducer in place.

Your fish finder will come with everything necessary for installation and operation on most boats. However, there are several situations which may require a different type of transducer. Inboard boats, wood or metal hulls, and sail boats create unique transducer mounting needs Alternate transducers and mounting methods are detailed below.

Portable Mounting
The standard transducer can be adapted for portable installations with a portable mounting kit available from most manufacturers. This accessory adapts your transducer to a suction cup mount for temporary installation on the boat hull or other surface.  

Trolling Motor Mounting
The standard transducer can also be adapted to mount on most trolling motors using a different accessory kit. This accessory includes a bracket and hose clamp that allows mounting the transducer to the body of most trolling motors.  

Thru-Hull Mounting
Thru-hull transducers install through a hole drilled in the hull of the boat. Larger boats or boats with inboard motors create turbulence that make transom mounting ineffective. Also, hulls that are very thick or are double layered, or made from materials such as wood or metal, (which do not conduct sonar signals) make inside the hull mounting inadvisable.

Now that you have determined the transducer mounting method you can begin installation of your new fish finder.
In addition to the parts included you typically need the following for installation and operation:
• A powered hand drill and various drill bits
• Philips and flat-head screwdrivers
• A ruler or measuring tape
• Pen or pencil
• 12 volt power source (your boat's battery)
• A fuse holder (if you are wiring directly to the boat's battery)
• Silicone sealant (for sealing drilled holes)