Spinnaker Halyard exit

dmax

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Jul 29, 2018
489
O'Day 35 Buzzards Bay
I'm replacing my halyards and masthead sheaves, adding a spinnaker halyard as my boat did not have one. Probaby won't ever get a spinnaker but I want to have an extra halyard. My question is, does anyone with one of the Isomat masts know how the spinnaker halyard should exit the mast head? There's a pin with two rollers that it looks like the halyard would be routed over (circled in red in the picture below) but that doesn't seem right as there would be a lot of friction and seems likely to jam sometime. Am I missing a sheave there? Alternatively, I could use one of the main or jib halyard exits as there are two for each of those.
 

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Jun 8, 2004
2,562
Catalina 320 Dana Point
Yes, you are missing sheaves, fully loaded those axles carry 2 each, while I use the internal halyard I'm real careful how I lead the halyard with that little roller. There is an external crane available that many recommend but requires drilling and tapping for 2 screws. You still need to get at least one more of the large sheaves for that axle to make the turn down the mast. I'll attach a diagram from rig-rite should show it all, there are places that may have the sheaves cheaper.
Masthead sheaves
 
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dmax

.
Jul 29, 2018
489
O'Day 35 Buzzards Bay
Thanks for the image from Rig-Rite, I didn't see that. I bought sheaves from them, not cheap but they had them, and have one for the spinnaker halyard. I'm not crazy about that set-up (parts 5 and 6 in the diagram) and can see why people add an external crane. Since I don't need it for a apinnaker, I think I'm going to add a sheave to the forward axle and run the extra halyard alongside the jib halyard. Thanks.