I just posted on the Grand Banks forum my results from using boracol, a product recommended by our surveyor for removing algae and moss from teak decks. I purchased a gallon of the product and applied it to the decks of our GB32. The results are great! No more of the ugly green stain that is prevalent here in the PNW. I cannot comment on the long term effects on the teak or caulking, but so far, so good.