Measurers Corner

Measurer’s Interpretations and Recommendations

Topic:Control Lines
Question:May the spinnaker halyard exit the mast above the deck?
ID Number:000020
Date:2008-08-04
Short Answer:Yes 
Answer:Proposed rule change: The spinnaker halyard may have the return inside the mast and exit the mast at any location or be wholly outside the mast. When a halyard block is used the top of the sheave of the halyard block shall be at the same height as the spinnaker halyard fairlead as shown on Official Plan 2.
Official Plan 2 is changed to indicate the Spinnaker sheave block is optional. 
Section:§IV-8.11 
Status:Affirmed
Action Date:2008-10-15
Sat Oct 19 10:37:29 2019
DateNameComment
2008-08-04Richard RobbinsAccording to Cape Cod Shipbuilding there are 3 ways they build masts related to the spinnaker halyard. 1) Halyard exits mast under the deck from sheave box; 2) Halyard exits mast close above deck (uses a block and cleat on deck); 3) Halyard exits mast high above deck (allows halyard to be "jumped") uses a cam cleat on the mast.
2008-08-04Richard RobbinsThis raises the question of whether a mast can legally be fabricated without the spinnaker halyard sheave box even though it may not be used. Since the sheave box is called out on the Official Plan it could be argued that it is required (even if then is not used).
2008-09-06Richard RobbinsProposed rule clarification and making the spinnaker sheave box optional:
The spinnaker halyard may have the return inside the mast and exit the mast at any location or be wholly outside the mast. When a halyard block is used the top of the sheave shall be at the same height as the spinnaker halyard fairlead as shown on Official Plan 2.

Change Official Plan 2:
21 HALYARD LOWER SHEAVE BOXES (MAIN AND JIB) - REQUIRED
21A HALYARD LOWER SHEAVE BOX (SPINNAKER) - OPTIONAL
2008-10-20Richard RobbinsThis clarified rule has been adopted by the Governing Board on October 15, 2008.