The three-hour window before dark is ideal — you’ll hook lots of fish after dark too, but you can’t see anything, just hear a lot of splashing. Once you’re anchored up, cast the crab up-current and let it drift back with the tide. Every 30 seconds, stop the drift and let the crab rise to the surface. Let it hang for 30 seconds, then go back to free-spool for 30 seconds, and repeat till you’ve covered all the prime water. A crab on the surface drives the tarpon crazy, but you can’t let it hang there forever; no crab swims that well.