I am not familiar with the 18.5. However, the tension on the lifting line on a 23, which must have a substantially heavier mast, is not that great. I would think a block attached to the bottom of the front bow pulpit (assuming you run the line aftwards to some place for the winch) would support the line. If you don't do this alone, running the line through such a block and aft to the sheet winches may be almost as easy, saving the cost of the electric winch. It all depends on how heavy the 18.5 mast is.