I just hauled out our 3807, mostly due to a leaking, original (1988) speedometer mechanism. It fit thru a 2-1/4” hole in the hull. Hasn’t worked in years. My thoughts were putting an updated transducer in there for more modern electronics might be cheaper than labor to re-fiberglass the hole and open me up to upgrade the electronics. Turns out to be true. Installer just enlarges existing hole by 5/8” and pops it in. Here’s the rub. He’s a bit gun shy. He says if I hit something it could shift it and leak. It’s flush with the bottom of the hull and sealed under the flange and threads through the hull with 3M 5200. I doubt you could move it if you try and if it does move, then the boat hit something that probably totaled it anyway. Don’t most larger inboard boats use thru hulls transducers? Doesn’t make sense to me, but I am old enough to know there’s always opportunity learn something new. I asked him to install it anyway and if that happens then it’s on me. I may learn the hard way. Thoughts?