Mastbase and cabintop blocks allow crew to raise, lower and trim sails from the cockpit. A variety of specialized blocks have evolved for routing lines aft.

Typical Boat Length:
Small Boat: 22' - 28' (6.7 - 8.5 m)
Midrange: 29' - 34' (8.8 - 10.4 m)
Big Boat: 35' - 42' (10.7 - 12.8 m)

1 Halyard This simple system leads principle halyards aft. Used by boats under 9 m (30 ft). Diagram Ref. Description Small Boat Part No. Midrange Part No. Big Boat Part No. A Mastbase block 222 1986 1990 B Cheek 2644 2606 3220 C Single 2652  —  — D Flip-flop 2142 3122 1987

3 Halyards Larger boats use special mastbase halyard lead blocks. Lines are routed out to deck organizers then aft to stoppers and winches. Stand-up blocks on a base are sometimes preferred for their complete articulation, but they hold halyards higher off the deck than specialized mastbase blocks. Diagram Ref. Description Small Boat Part No. Midrange Part No. Big Boat Part No. A Mastbase block 222 1986 1990 B Deck organizer 9001 9001 9006 C Winch 20.2PTP 35.2PTP 40.2PTP D Single 2636 2660 1540 E Stand-up spring 097 071 1634 F Stand-up 2652 3227 3244

6 Halyards Modern race boats lead halyards and control lines straight aft through deck organizers so they can be used on either cabintop winch. Diagram Ref. Description Small Boat Part No. Midrange Part No. Big Boat Part No. A Mastbase block 1986 1988 1990 B Deck organizer 9001 9006 9006 C Winch 20.2PTP 35.2PTP 40.2PTP D Crossover block  — 1984 1981

Over the Top Special “over-the-top” blocks are required to route lines over an outside corner like the front of a doghouse or coaming. Diagram Ref. Description Small Boat Part No. Midrange Part No. Big Boat Part No. A Mastbase block  1986  1988 1990 B Mastbase block  1986   1988 1990     C Over-the-top block 3002 3002 3002

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