Replacing wire/rope main halyard

[stanirish]

My 1975 31' C&C 1/2 Ton main halyard needs to be replaced; there was only 12 of these boats made but the C&C 30' sailboat mast is likely the same. The main halyard is a wire/rope design likely 1/8" wire 3/8" rope. From my research I read that most masts were designed to have wire/rope halyard sheaves that will work for both wire/rope or just rope? I'd prefer to replace the wire/rope with just rope such as a Vectran or Dyneema. Everytime I raise the mainsail I worry about the strength of this wire/rope seeing how worn the current halyard is.

I'm planning to attach a mouse line to the halyard from the base and pull the wire/rope out from the top and then attach the new Dyneema and pull in reverse up and through the sheave down through the internal mast and out the base as videos suggest but would first prefer to hear others with the experience of doing this. Will the sheave on this mast take just rope? Any input appreciated. Wow this stuff makes me nervous...

 

[Roland5048]

Will the sheave on this mast take just rope?

Depends on the sheave. I replaced the rope to wire halyard with rope years ago. My sheave could take both, fortunately. You might have to go up and take a look or maybe you can view it with binoculars. Don't be nervous about this. There's always a myriad of more serious boat issues to keep you awake at night.

 

[Joe]

Build a "tapered" halyard with dyneema core covered over the back half (that is handled, winched and cleated but does not run through the masthead sheave) with a softer polyester sheath. Difference in diameter between core an cover is 1/4". So a 3/8 line needs a 1/4 core. On my boat, I use a 3/16" amsteel core, I use the core of inexpensive 5/16" double braid to fish that core into place. The "taper" or "bury" splice is used to smooth the transition. The halyard's strength is all in the core and it will easily fit your existing sheave. Dyneema strength is huge... 3/16 more than enough. You may want to go larger because of the feel and function in winch. but price goes up accordingly.
The Samson website will have instructions for the very simple splice, no special tools need. A phillips screwdriver to open the weave, a very sharp pair of scissors, razor or xacto knife, some whipping twine and a heavy needle for lock stitching both ends and the splice, a ruler and tape. that's it. If you want to put an eye splice in the dyneema's end for a shackle.. the process is very easy on single braid line, and if you do, install a "luggage tag" long loop eye that will allow you bend the shackle on and off easily.

 

[RoyS]

The time to be really concerned about the strength of your halyard is when hoisting someone up the mast. Who knows the load limit that will cause the old halyard to part or the original winch fasteners to shear? If the main sail falls no one will be hurt, but if the guy at the top of the mast inspecting the sheave falls, that is a different story. Worry about that.

 

[jssailem]

Hi, just 2 years ago you were discussing a mainsail insignia for an Island 17. Sounds like you have a new to you boat. Congrats.

This 1975 sailboat with wire/rope halyard is 45 plus years mature. In the day they made sheaves that had 2 grooves. One for the rope, and a narrow groove in the center for the wire. The sheave is said to handle both. It is a compromise. You can try, but when you try to get that last foot of sail up the mast you will be stretching the rope and there is a possibility the rope could start to weaken as it strains and gets squeezed into the smaller groove.

Best practices is to:

1. Replace the sheave with a U shaped groove designed for rope.
2. Take the sheave off and grind/sand the groove until it is U shaped.

How long has it been since the mast has been serviced? How old is the standing rigging?

You sail in the SD Bay, maybe dream of sailing out beyond Pt Loma, it maybe time to do a mast/rigging refit so that the boat will safely carry you on your adventures and return you back to a sheltered port.