Most boaters view transducers as a necessary evil. But technical breakthroughs have spawned a whole new generation of transducers that don't have many of the problems experienced by users during installation, use, and maintenance. Here's a quick rundown on what's out there.
Through the hull is still the most common way to install a transducer. "No hole" inside-the-hull transducers can be less effective, especially in terms of signal loss and decreased depth range. But commercial fishermen have started connecting their fishfinders to a new breed of 1kW, 2kW, and 3kW inside-the-hull transducers with remarkable results. Airmar (www.airmartechnology.com) has versions of its M260, R199, and R299 transducers that complement many common fishfinder models. Garmin, Humminbird, Lowrance, Raymarine, and other companies make transducers that can be epoxied in place inside the hull and are effective in transmitting acoustic energy through fiberglass. Several versions have adjustable liquid-filled mounting bases to compensate for a hull's deadrise angle.
The New Through
Trailered boats can wreak havoc on transducers. Transom-mount units encounter turbulent water from props, making sounders unusable at higher speeds. Bulky through-hull transducers require fairing blocks that can make it impossible to launch a boat. But there's a new family of "tilted" element transducers that have a near flush-mount housing. The transducer follows the deadrise of the hull up to 22 degrees, and the internal element or eye tilts downward to compensate for the deadrise angle of the hull. Because it's almost flush with the hull's outside surface, no bulky fairing blocks are required.
The Need for Speed
Need to clear debris or replace a broken paddlewheel? You need to remove your boat speed transducer. Airmar's CS4500 ultrasonic transducer has no moving or protruding parts. Instead, it emits a signal into the water that senses movement within a tenth of a knot. In some cases, you can even use the existing through-hull housing to install the ultrasonic transducer without diving beneath the surface or hauling the boat.
Smart transducers add intelligence to the common transducer. Instead of delivering signals to a another device, smart transducers have the electronics embedded inside them. The output works with any NMEA -compatible display. Maretron's DS T100 Smart Sensor (www.maretron.com) fits inside a single 2" through-hull fitting. Airmar makes a line of similar products: Some only display depth; others add speed and temperature functions; others have downward or tilted depth beams. As a bonus, both manufacturers use 235kHz as a depth frequency, which means they won't cause any onscreen interference with other equipment operating at frequencies of 50kHz or 200kHz.
If you hate the thought of stringing cables throughout your boat, you can buy wireless units that minimize the time, drudgery, and expense of installation. TackTick Wireless Electronics (www.oceanequipment.com) produces a line of depth, boatspeed, water temp, wind, GPS , and compass heading sensor intelligent transducers that communicate with wireless displays that can be mounted most anywhere.