Today, with low-stretch spectra line available, there's not much reason to use wire halyards, esp. for someone who primarily cruises and daysails. You'll save on the cost of the rope/wire splice, and you won't have the unpleasant experience of being fishhooked by the inevitable deterioration of the wire portion. The difference in stretch is too minimal to affect performance, and you'll have a more crew-friendly boat.
Regards, James Libby S/V Blithe Spirit

Replacing the wire/rope halyards with all rope should be easy - if your top of mast sheaves are of the type which can accomodate both. On the C&C 30, the sheaves have a small groove in the center for the wire and a larger one on outside for the rope. Thus, they can handle both. Your main concern would be stretch. The better line you buy, the less stretch. Some of the newest spectra lines have very little stretch, but if you buy Sta-Set or the equivalent, you may find yourself having to tighten your jib halyard during a race. I used Sta-Set X and was not satisfied - moved the jib halyard to T-900, which has about 1/10 the stretch. Some of the newer lines are even better.
Good luck.
Gary Nylander
C&C 30 Penniless

A word of caution: if you switch from wire to rope, you need to be sure that the wire has not left any burrs on the sheeves, otherwise they will cut into the rope (riggers suggestion). Also, you can replace the sheves with Drelin pulleys and save a bit of weight aloft (for the fanatics amongst us). Finally, you can switch the rope halyards end for end and distribute the wear points for longer life.
CW

To see if you need to replace the sheaves simply try to pull the rope halyard tail through them. If the line runs smoothly good to go. You may need to attach a small messenger line while doing this so that you don't loose your halyard.
Wouldn't worry too much about the weight issue. If the halyards are in good shape continue using them. When it's time to replace go with the all rope. Most people don't need the expense or short life of the exotic braids, I'd suggest a decent low stretch line such as Sta-Set X or equiv. An added benefit of the rope halyards is that they're much easier on painted masts.
Jerry

I would recommend using 5/16" spectra core line, to replace your rope/wire halyards. Breaking strength is about 5,000 lb., with very little stretch. You could go to 3/8", but not needed. Working on deck with line is much more comfortable than wire. You can make up the splices and shackles at home. Then attach a small line to your old rope tail, and pull it through the mast. Attach your new rope tail to the small line, and pull it through the mast.Use duct tape to make your joints, so the splice does not break in the mast when pulling. When selecting the new line, review manufactures specification on stretch, go for the absolute less amount of stretch you can find.
Larry

Jerry,
You can go with all rope without premature wear. I asked my local chandelery about doing that for my 32, and they said no problem. They were Marine Exchange, 800-888-8699. They also do lots of mail order and have competitive prices.
Tom Anderson
C&C 32 Nonpareil
Marblehead, MA

I use 3/8 spectra cored line on a C&C36 with no problems for the last 4years.
Gerry/Mintaka

My two cents worth on this one - we have a 30 with 3/8 jib halyard out of T-900 and 7/16 on the main out of Sta-set X. The sheaves are unmodified and the lines are OK. The T-900 stretches less than the X even though it is smaller. I will replace the main with T-900 or equivalent at 3/8 when needed. However if you are cruising, go with the larger stuff to get a better "feel" - the T-900 is rather stiff as are all of the high-tech lines. They don't coil well, either. When we bought Penniless, she had the old wire to rope halyards aboard which had already been replaced with 7/16.
Gary Nylander----------

Jerry,
The only way to know if your sheaves will damage a new rope halyard is to inspect them for wear. Does the rope part of your present halyard come in contact with the sheave, and if so has it been damaged?
As far as rope diameter and material, you have to be the judge of how you use the halyard. For example, do you cruise or race? When cruising on your 30, you may be able to hoist the main by hand rather than using a winch all the way. If so, trying to hoist with a small diameter line may be less comfortable than with slightly larger diameter, I would think that 3/8" would be the smallest and personally I would use 7/16" just for comfort.
As far as the head sail halyard, rope to wire may be the better solution on a cruising boat because we cruisers tend tend set things once and forget them. If you have roller furling, the wire will probably stay where you set it, without stretching, better that rope.
My $0.02
Joe Longtin
Moonlight C&C 35 MKIII
In Beautiful Downtown Bayfield

As regards a messenger line, a trick that I learned from the riggers on my mast rebuild: on the original line, use a sharp tool along the lines of a fid or a small Phillips screwdriver and push it through the line so that the loosens up. Then, with the screwdriver end, push a loop of the (small diameter) messenger line through this opening and then tie a bowline. Strong and won't slip out from the tape if a snag occurs.

I accomplished the replacement of all my wire-to-rope halyards by over lapping the new/old leads by 8" (this allows for some flex when rounding the masthead halyard pulley), and using a fine binding line at both ends. Use tape if you want...this would allow for some taper when the new lead enters the masthead. This is an easy and quite simple process when going from wire to 3/8 Sprectra.If your using 7/16 Sta-Set X I think you'd be fine by butting the new/old leadsand taping with 2"duct tape. Yes, it's tough to remove, but you won't lose your old halyard. If your worried about it, sew some threads, then using 2 " packing tape.
* Your sheaves vary in diameter on the 32's with the largest sheaves appearing in boats vintage '84 (circa) and older....making this process easier.
Chris V.Mariah - 32'

It depends on what you want to do with the boat. Our wire/rope halyards had already been replaced wiht 7/16" rope when we bought our 30. We found the genoa halyard would stretch over time while racing. I believe we had Sta-Setor equivalent on the boat and that stuff is pretty stretchy. It was OK for cruising, but was a pain to keep taut. We replaced it with 3/8" T-900 and it works great. You pays your money and takes your choice.....
Gary Nylander, 1980 C&C 30 Penniless

A friend of mine with a C&C 35 wants to switch from wire&rope halyards to all rope.
Questions. Does he need to change the sheaves at the mast head? What size line should he use?
Kind Regards, - Pete Drage

Pete -- I've heard arguments both for and against on the list; but the prevailing wisdom seems to be that the "combination" wire/rope sheaves with the slot cut in them for the wire don't support the rope halyards as well, especially when they're under tension. I switched over to Sta-Set X halyards this spring, and changing out the sheaves was a pretty easy job, at least with the mast down. The replacement sheaves came from :
Metalmast Marine

55 Providence Street Putnam CT 06260

The wire/rope sheaves can be modifed for all rope by filling the wire groove with epoxy, then grinding/sanding down to match the rope groove.
PeterO

My riggers (The Rigging Loft/Rigging Only, Fairhaven MA) did that when I switched over six or seven seasons ago. Used an aluminum filled epoxy putty, and turned the excess down on a lathe. Last season, the filler started to separate from the sheave. Perhaps it was UV exposure, perhaps they didn't clean the groove completely enough. They'll stand by their work and redo it (Tom and Joe are standup guys), but the technique does have little to recommend it.If you can find rope-only sheaves that fit, I'd recommend doing that.
Dan

Peter,
I'm sure you will get different opinions but I changed out the wire for rope on my C&C 38-3 6 years ago. I did not change the sheaves. I replaced the first halyard this year because of wear at a clutch.
He should ask the outfit he where he purchases the line. They have always been very reliable.
I will not have the shackle spliced on in the future. The one I replaced this year I used a bowline and it has held fine. It gives you the option of switching ends if wear shows in one area. Also saves you the price of the splice.
Bill

I, too, have had no problems with the original sheaves when switching to rope. I have Sta-Set X for the main and T-900 for the genoa.

Same story here - switched to T-900 and have not replaced the sheaves. Not an issue.
John