Junk in your (CB) trunk
When you haul out, check to see if anything's caught up in your CB trunk. By the end of last season, we had an entire mussel colony up there which prevented our board from dropping. I just ran a hand saw back and forth along the length of the trunk opening to clear the blockage. Make sure your board's tied off in its upright position though... once I cleared the obstruction, mine fell and the cable snapped (I'm almost certain it was about to break anyway, but still worth watching out for). Our 23' sails okay without the board down, but she does make more leeway.