thru hull transducer vs transom mount
Thru hull transducer vs transom mount
Thru hull transducer
Through-hull transducers require that a hole is cut in the hull, so their installation is more involved than a relatively simple transom mount. This type of transducer usually provides the best performance.
They are also more difficult to access for periodic cleaning, which they may require more often than a typical transom mount transducer. Owners of trailerable boats with through-hull transduc- ers must be careful not to damage it when launching or loading the boat.
To keep the transducer facing squarely downward into the water column, a fairing block must be used. The fairing block is installed parallel to the flow of water to ensure proper boat handling, and this will not necessarily be the same from hull to hull.
Fairing blocks
The purpose of a fairing block is threefold: to compensate for the deadrise of the hull, to reduce drag, and to create a smooth surface for water to flow cleanly and unaerated across the face of the transducer. When a fairing block is correctly installed, boat drag will be minimized and the flow of water over the transducer face will be free of bubbles and turbulence.
A standard fairing is of a similar shape to its companion transducer. By contrast, a high-speed fairing projects a longer, more streamlined form. This elongated wedge shape cuts the water into two streams which flow along its sides towards the tapered end, where they will smoothly rejoin. The result of a well-installed fairing is excellent fish finder performance above 15 knots.
After the fairing is cut, it must be shaped to the hull as precisely as pos- sible with a rasp or power tool. A tight fit will allow water to flow more smoothly over the transducer. If the transducer is recessed more than 0.5 mm (1/64th inch) inside the fairing, you should either shim the transducer or carefully file or sand the fairing until the two are flush.
A fair amount of skill is required to achieve a proper through-hull installation. If in doubt, please contact us.
Transom Mount
Transom mounting is the simplest method of transducer installation and is most common among smaller boats. The transducer is installed on the tran- som, slightly below the waterline. The transducer face should be at a slight angle forward so as to reduce the effects of turbulence and aerated water.
