The fish finder transducer available for your machine may vary from a manufacturer selected unit packaged with the display to a variety of optional units.
You’ll likely find transom mounts, thru-hulls, and possibly a shoot-thru unit as options.
Airmar B744V
Transom mounts are normally constructed from plastic while a thru-hull unit can be either plastic, bronze, or stainless steel.
One of the most important decisions youll make when outfitting your fish finder or black box sounder is what type of mount you want.
A transom mount only requires you drill a few small holes into the transom while a thru-hull requires you cut a large hole through the bottom of your boat.
A thru-hull installation can be complicated and is often best left to a professional marine electronics installer, especially on a fast boat where the unit will be mounted flush with the bottom of the hull.
Another option is a shoot-thru, these mount inside your hull with no need to drill any holes.
Your hull must have a space big enough somewhere in an accessible bilge area where you can mount the unit.
Also, it is important that the shoot-thru be mounted in an area of the hull with no coring materials sandwiched into the fiberglass.
Airmar M260, a modern high-performance shoot-thru fish finder transducer.
In the past, most experienced anglers seeking to optimize their fish finder performance opted for a top-notch thru-hull.
Today, with the recent release of 1000-watt capable transom mount units like the Airmar B164 Tilted Element and some very impressive shoot-thru units like the Airmar M260 things have changed for the better.
Nowadays you can achieve outstanding fish finder performance with any style of transducer. Youll find recreational transducers available in frequencies ranging from 28 kHz to 200 kHz, with 50 kHz and 200 kHz the most common. Some units will also provide speed and water temperature data.
Generally speaking lower frequencies penetrate deep water better and have wide beam widths while higher frequencies have a narrow beam and show more detail.
Usually you won’t have to choose a single frequency anyway as most fish finders on the market today are dual frequency capable, so youll get the best of both worlds.
The most common dual frequency setup will be using 50 kHz and 200 kHz.
A 200 kHz xducer powered by 500 or 600 watts will be able to read bottom and see fish in water up to about 400 feet deep. To read deeper youll need to use a low frequency like 50 kHz, which should read bottom at slow speeds to at least 1500 feet.