Original equipment all line halyards on the Catalina 34 and Catalina 36 are Dacron. But Dacron has too much stretch to maintain good sail shape. Unlike a wire halyard with a Dacron tail, all line halyards are under high load while the line is around the sheave. When a loaded line passes over a sheave, it needs the support of a "U" shaped groove. High tech lines that have low enough stretch for halyard use require the additional support of a "U" shaped groove in the sheave when the line is under load.

A better choice is our #Z1970 sheave shown in suggested products below. It provides the "U" shaped groove appropriate for all line halyards. Low friction ball bearings ease hoisting or dousing the sail.

Outside diameter: 3-3/16"
Inside diameter: 1/2"
Width: 11/16"

Catalina reports that they would occasionally have to sand down the sides of the middle bushings for these sheaves to fit properly. The sanding was required due to variations in the welded masthead into which these sheaves and center divider plate were installed.