I just bought a Hummingbird 997 SI fo my 1990 Gulfstream it comes with a transom trans ducer. The rep says it will work. I sent him a pic of transom and he marked the spot where to install. The truhull Hummingbird offers is plastic and that does not thrill me at all. A compatible ducer is way more than I can afford. The transom mount ducer is huge 3 x5. Let me know if you have had good or bad luck.
Thanks..
Thanks..