I have a Marcum Showdown Troller, and it REALLY cuts down on drilling. Carry a bottle of water with you, scrape down to bare ice and then pour a small puddle (an ounce or so) to set the transducer on. (You can't have any air between the 'ducer and the ice.) If the ice is mostly clear, you'll get a fully usable look at the water column. If no fish are showing, move.
