Hafken 29 mm thru hull

I have a few Harken 29 mm Thru Hull Blocks on my sail boat . They are mounted on some vertical surfaces which i think is not common . I decided i would like a little less rain water to flow in thru these holes and in order to accomplish this I have replaced the existing face plate with one that has a slight rain gutter at the top just big enough to direct water that contacts the hull above the block its not a water proof solution but my point of view is that a bilge pump should never work harde