Wrecks and Local Resident Fish

Was just curious about how long it takes for a newly sunk wreck to start rusting away and attracting resident fish. Just how exactly do fish like tog, cod sea bass, conger eels (the long black ones with the whitish belly, not ocean pout) or ling choose a nook or hiding place to hang out inside the wreck?? And how exactly do you tell whether your rig is on a certain part of the wreck when you drop your line/bait down? And if anyone has any great underwater shots of some sunken wrecks in the NY area, that would be nice. If sure some of you have dived in or around these wrecks. Let me know.