Originally Posted by Capt.Bill11
Does your hull have any dead rise angle to it at the area you mounted the transducer in? If you the beam from the transducer is shooting off at an angle instead of straight down.
Generally, just about anything other than a jon boat or a barge will have some dead rise. That is why you have to pick and chose the most reasonable position usually based on accessability, prop cavitation, water past the hull while moving or planning cavitation. These are all concessions that have to be made when shooting through the hull. The transducer will be slightly at an angle and will be slightly inaccurate - how much? I don't know I never calculated it. I can tell you thid though, It has never beed a problem on any of my sailboats and so I don't expect it to be a problem on my power boat. keep in mind that these inaccuracies bcome greater at greater depths. My concern was never how deep the water is but rather how shallow it is. The shallower the water, the more accurate the transducer will be in regards to actual depth.
Another real concern is that most transducers will not shoot accurately through a fiberglass boat that is more than an inch thick or a hull that is cored. Even if the hull is not cored and is less than an inch thick, I will still probably lose at least 20% of the definition of the fish or the bottom.
If these are concerns, Then a wedged through hull mounting will be required. I personally don't need that type of accuracy or definition because I don't fish.