I doubt they have a sidescanner fishfinder at west marine, at least not at mine. Hey, who says you need metal for a fishfinder? You guys know how the sidescanners work? Sends a signal down, and when it bounces back up, it uses the time to took to travel up to create an image of the bottom. At 35 feet deep, the one he linked to has plenty of sideview to see the ski. This isnt a traditional vertical view scanner. The way they see fish is when the signal travels through their air sac, it travels faster and then slow down, so depending on the depth, it will now it should of come back faster, so it marks it as a fish. If theres any air bubbles in the ski, you could be able to find it with a regular finder, but I highly doubt it. If any, a sidescanner is your only bet for seeing onto the bottom.
Other then that, rent some gear and go searching yourself. A good sized tank is good for about 1 1/2 hours if you know how to breath correctly, even longer if your used to SCUBA.
Cameras wont work. Visibility is completely gone after the first 15 feet in places like that. And if you guys got a lot of rain like I did, the water probably looks like coffee. The only way to physically look for it is to do it with your hands, feeling for it.
You better let us know if you find it! Oh, and I'd scratch the idea about trying to 'rent' a fishfinder. Those sidescanners are usually only used on offshore tuna fishing boats, nothing inland. And the money it would cost to transport it from here to there would be way too much. (and for the guy to come with it). Your best bet is to find a store with a good return policy, use it and try and return it, or get an ebay unit and then resell it if you dont want it. Bass fishermen dont have sidescanner, they're not worth the money for such small narrow waters they're usually on. And come on, they're rednecks, they dont have money!
-meaty