Like someone before me said . . . "If you're not using a depth finder, you're wishing, not fishing."

Although I suppose it depends on what your fishing goals and expectations are that determines whether you bring one or not.  Honestly, these things are so light and easy to use that I don't understand the "added weight" argument.  Anyway, w/o a locator you are paddling over trophy fish sitting on midlake structure.  Shoreline is easy enough to read to give you a pretty good idea of depth and what's down there but when you come across midlake structure . . . that's "treasure buried in a field" man.  I know of places on Pickerel, Jean, Cirrus, Quetico, Batch, Kasa where the bottom comes up from 60+ feet to 8 feet in the matter of a paddle stroke.  All the big fish party mid-lake.  But, if you don't want to catch them, that's fine by me.