Replacing H16 masthead with new dual sheave head - questions

The single sheave in my original '81 H16 masthead is blown and I have decided to replace the masthead with the new dual-sheave style, part #20614001. Will I be able to reuse my original halyard cable? I am prepared to cut and remake either the shackle end or the thimble end if needed in order to route the cable through the head, but I am wondering if the spacing measurement between the halyard shackle and the hook stop on the cable will be different thanks to the new sheave arrangement. If so and the distance is shorter I can easily accommodate by remaking the shackle end (Murrays or Grainger sells the single shank ball stop a lot cheaper than a new halyard), but if the distance is longer, then I could relocate the halyard hook on the mast or ...?

Anybody done this? Any other tips or gotchas I should know before proceeding?

Thanks!
Stuart

Has anyone done this replacement? I'm curious.

Stuart, how messed up is your original masthead? I assume a broken sheave. Sometimes you can find a used masthead on eBay, often with the wire halyard.

The halyard shackle pin to stop measurement is different between the two mastheads. I believe it is shorter, but I'm not sure of the exact measurement.

The Comptip masthead was meant to be used on the Comptip. I'm not sure why you'd want to change to it vs. finding a used aluminum masthead (probably for cheap on eBay).

If it helps any, a dealer sent me a comptip halyard by mistake for my all aluminum mast. I count not hook the comptip halyard onto my mast, it was 1 inch too short.



This means that with the new dual sheave, your halyard would be too long and you'd have to lower the hook to compensate or live with the sail being an inch or 2 lower.

One question that I don't know the answer to and that you should find out. Does the new masthead for comptips fit the old all aluminium mast, regardless of the halyard?

_________________
Marc...
1978 Hobie 16 Keoke, sail# 36 84

Wow you guys really came through on the answers I need, thanks!

Yes, the sheave in my original masthead, being plastic, is deteriorated, specifically the edges have broken off in spots, allowing the cable to slip off the wheel. I figured I would run the risk of the same thing happening if I buy a used replacement, so I am satisfied to spend the money for a new masthead -- buying a bit of peace-of-mind, if you will. I cannot cite where, but I am certain I read that the new dual-sheave masthead will fit onto the aluminum mast. I'll let you know if that's wrong! Will have to drill new rivet holes, that's no biggie.

Marc, thanks for the pic...your line is key: "your halyard would be too long.." I believe I can easily remedy that by cutting and re-crimping a new stop for the shackle, making the halyard cable shorter. Plan B is to put a new hook on at the right place, or just buy a comptip halyard.

And if the new masthead doesn't fit the mast, then I'm off to eBay! Or find the post about the guy who can fabricate a new new Delrin sheave for my masthead -- but his repair cost is as much as buying the new masthead.

I'll let you know how it goes...

Stuart

Or you could do this:
http://www.hobiecat.com/forums/viewtopic.php?f=14&t=28129&p=117139&hilit=sheave#p117139

Or
http://www.dailymotion.com/video/xd19u1_hobie-16-mast-repair_sport

_________________
Marc...
1978 Hobie 16 Keoke, sail# 36 84