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Sheave Box Internal Single Line Reef

Part #: Z2826
Installed inside the boom and used for internal reefing lines on the Catalina 28, and newer Catalina 30, Catalina 310, Catalina 34 and Catalina 36's. The box has four vertical plates to provide separation and proper spacing. The compression tube also functions as the axle for the sheaves to rotate upon. Two sheaves are included allowing one box forward and one aft to handle both the first and second reef lines.
There are two of these units inside of each boom. One is mounted just aft of the gooseneck for the forward reef, another a bit forward of the aft end of the boom for the aft reef.
• Base: 3" x 3"
• Height of two center divider plates: 3"
• Height of outside plates: 2-1/4"
• Sheave OD: 2"
• Sheave ID: 1/2"
• Sheave width at hub: 0.650"
• For line diameter: 3/8"
Warning: Since the aluminum compression tube passes through the vertical plates of the box, corrosion will occur at the interface unless protected against. Corrosion is also likely to occur between the stainless steel mounting bolt and the inside diameter of the compression tube. Once corroded, it may be difficult or impossible to remove the bolt from the tube or the tube from the frame, or the entire assembly from the boom.

To facilitate future service, we highly recommend application of Marelube TEF pictured below to prevent electrolytic corrosion between the bolt and compression tube and the compression tube and the vertical plates.

Technical Support

Complete Catalina 30 boom drawing
Remember that part number F8069 is the extrusion only.

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