"Through-hull" Transducer
"Transom-mounted" Transducer
Navigation Menu
Types of Transducers and Installations
Nanticoke Maritime LLC
214 295 5733
A transducer is best described as an electronic device that converts input signals of one kind into output signals of another kind, such as sound waves to electrical waves. In the case of fish-finder or depth finder transducers, an electronic ping sounding is emitted from the transducer, bounces from an object which it intersects, and is instantaneously received by the transducer. An image below the boat is detected from the emitted and returned “pings” and is translated to an electronic image recorded by the onboard electronics. The result is generally made visible on the screen of an on-board monitor. Boaters and fishermen use transducers mounted on or in their boats to detect images of fish, bottom structures, topography, depth of water and generally aid in navigation by locating images below the bottom of a boat. And, of course, there are many different types and models of equipment to suit most any user requirement. Many boat owners and fishermen are now equipping their boats with multiple transducers and electronics which perform various functions. The method and type of mounting a transducer used on boats oftentimes becomes very confusing. There are typically only 3 types of methods of mounting a transducer in a boat. Transducer mounting and adjustment problems comprise the majority of all marine electronics troubleshooting issues.
What is a Marine Transducer?
The "transom-mounted" external transducer is externally mounted on the transom whereby the face of the transducer makes contact with the water. Typically, these are the most effective, the easiest to service, to adjust for an optimum sounding, easily replaceable and, of course, the most popular. This type of transducer mounting allows for maximum performance of your electronic equipment as designed by its manufacturer. To mount a transom-mounted transducer, screw-holes are required by drilling holes below the waterline of your boat. Review and understanding your boat warranty disclaimers and the disclaimers made by the electronics manufacturer should be considered before mounting this type of transducer. Many boat owners are justifiably reluctant to mount transom-mounted transducers. Oftentimes they can be very cantankerous to adjust properly and generally will leak when you least expect it. There is an abundance of advice on "how to drill holes in the hull of your boat".
click thumbnail to enlarge
"Shoot-through" the Hull Transducers
The "Shoot-through" the hull type transducer is mounted inside of the hull, usually in a bilge, sump or keel, permanently adhered to the cockpit side of the hull with an epoxy or may be contained in a liquid reservoir. The sonar ping emitted from the transducer must adequately penetrate a solid unblemished hull material. Hull material actually will absorb or muffle much of the sounding from a transducer. There must be no voids in the layers of glass layup, no uncured or dry glass mat or resin bubbles to muffle, thwart or distort the emitted sounding. Most often it is impossible to investigate the quality of the glass layup you are seeking to "shoot through" to determine its suitability. The transducer has no contact with the water outside of the boat. "Shoot-thru's" are generally installed to avoid the necessity of making screw-holes in a transom below the waterline, for protection, and in most instances, will reduce or compromise the effectiveness of the transducer sounding. Other compromises are made in regards to eliminating a speed wheel, if equipped, and recording water temperature. Unlike the easily maintained and adjustable transom-mounted transducer, this method of mounting is generally fixed in place with a bonding material and cannot be adjusted, serviced or changed without the likelihood of destroying the transducer during removal. The user generally will install his transom-mount designed transducer in this manner and will settle for reduced performance as a compromise to sacrificing his boat hull as a "trade-off" for screw-holes and leaks and, of course, it may not work at all. There is also an abundance of advice on "how to install a shoot-thru".
click thumbnail to enlarge
The transducer "Through-Hull" is permanently installed in a "through-hull" hole on the bottom side of the boat hull whereby the face of the transducer is in direct contact with the water. It is usually “faired” to the hull deadrise (angles) so as to cause its beam to be parallel to the surface of the water. This transducer is fixed, cannot be adjusted, and is most always found on larger boats. They are usually the most expensive to purchase, install and to replace and seldom are found on trailer boats. These are the most permanent of all types of transducers.
click thumbnail to enlarge
Nanticoke Maritime LLC
"Transom-mounted Transducer"
"Shoot-through-the-hull Transducer"
"Through-hull" Transducer"
