Leading halyards and control lines aft to the cockpit allows crews to raise and lower sails or make tuning adjustments without moving to the mastbase. Because space is limited at the mastbase and on the cabin house, a variety of specialized blocks have evolved for routing lines aft.
On their way to the cockpit, halyards frequently must negotiate changes in height as they are led to winches or cleats on top of doghouses and cockpit coamings. Mastbase blocks and special-purpose Over-the-Top blocks, used in pairs solve the problem of negotiating height differentials. The mastbase block is used at deck level, and the Over-the-Top block is used at the upper level.
• Low profile, lightweight
• High-load sheaves