Speaking of crankbaits, trolling is the rule when you need to cover acres and acres of deep structure. Not only do trolling techniques allow you cover water quickly, they are effective for triggering late summer walleyes. Both crankbaits and live bait spinner rigs, properly rigged, can be trolled in super deep water. Right out of the box, some crankbaits run very deep. However, no company that I am aware of manufactures a crankbait that runs down to eighty feet on its own merit.
Help is available in the form of line weights, snap weights, and special lines.
New high tech lines, such as Berkley Fireline, allow deep diving crankbaits to achieve even greater depths. Anglers can gain as much as twelve feet of additional depth by simply spooling-on six pound Berkley Fireline. Lead core fishing line will drag crankbaits to unbelievable depths. But because of the added bulkiness, you will need a large capacity reel. I've found that my Abu Garcia 6500's offer enough line capacity to accommodate lead core line.