Hey, they're right, if it is nuetrally buoyant, your screwed unfortunately, you'll have to wait for it to wash up somewhere and hope that someone reports it. If it did sink, which it most likely did completely, then heres what you do.
First get a big heavy anchor, and a very buoyant buoy. Sink the anchor done where the approx. location is (within like 50 feet), and make it so the line in the water to the bottom is taught.
Take another very long line, and get your SCUBA gear out, and head down there. Tie the line around the base of your anchored buoy, loosely so it will swivel around. Make one circle around the anchor holding onto the line you tied around the buoy line base, and on completion of that circle, let the line out in your hands a few feet, so basically, you can guarentee you'll cover everything in that circle. This is how we found our outboard. After being on the bottom for 3 months, it was in great shape still, there should be no barnacles on it, since its too deep for that, mabye some fuzz, but the hull will look like new upon cleaning, unless water has seeped into the gelcoat and destroyed it (this takes at least a week or so).
By the way, a note of caution, you wont be able to see anything at all down there (at whoever may SCUBA), a flashlight wont help either, as its rays extend only about 3 inches! You have to feel around until you run into it. And yes, it sucks a lot to do that, because you may find some scary stuff down there, and it will be pitch black, I guarentee it. But for 5 grand, its more then worth it.
Found a couple eel pots and anchors when I searched, and also came across then occasional live crab that would kick mud in my face :frown: but we still found it!