Re: Thoughts regarding Shoot Through Hull Transducers?
Bruce has the way you determine if it will work, and while you are at doing what he said, build your dam where you want to mount it. Plain water is all you need for the test and if you have a lot of dead rise at the transom, and that is where you want to locate it, just fill your bilge with enough water to cover at least the lower half of the transducer and you will get your answer.
If you like the response you get as compared to his over the side suggestion comparison, hard epoxy (not soft silicon....you want the mechanical vibration to move through the glue and silicon is soft and attenuates it) the transducer as vertical as you can get it in that location....obviously after you clean up the grease and water and other bilge crud from the transducer and the location. A little sanding of the area wouldn't hurt to help the epoxy adhere.
On Achris's "no tin cans" (aluminum hulls).......Depth finders are acoustic (sound....percussion) devices, not electronic devices. The transducer is a piezo device that converts 50KHz or 200kHz electronic sine wave pulses into mechanical vibrations. These vibrations go through "tin cans" like they weren't even there. Water does an excellent job of amplifying sound which makes it easy for sound to travel through it. My current boat is my second tin can with the transducer mounted internally.
If you have any doubts and are not technically inclined about sound being amplified through a dense medium such as water, have someone go by you with their boat at say 100 or so feet away from you at 20 mph (for a number) and with your head out of the water try to hear the prop spinning. Then duck under the water and listen again. While you are down there listening, think about what the fish hears when you think you are sneaking up on him with your engine/prop running, and his acoustic sensors are probably 100 x more sensitive than yours or mine.
Mark
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