We use a block and tackle with a split backstay on our J/36. The 4:1 tackle pulls a pair of sheaves down the two split backstays, pulling them together to tighten them and bend the mast back. The power in this type of setup depends upon how high up the split starts. When it''s not needed, the tackle can be unrigged to allow passage through the spit backstay - very convenient for the transom ladder. It also doesn''t leak hydraulic fluid, and even if the adjuster were to break (not likely), the stay(s) would still be there to keep the mast up.