Some questions you should ask yourself:
How do I intend to use this boat?
Sunny light wind day sailing?
Weekend with overnights at a dock?
Weekend with overnights on anchor?
Rough water and high wind sailing (over 20 mph)?
Mini cruiser day and night sailing in all weather away from easy sources of assistance for extended periods (that's us)?
What am I willing to invest to make this boat better than it is...
etc.
***I take a stab at some of your questions below:***
questions:
An opportunity to acquire a mast sans boom and several rig components, some of which may be in better shape than some of what I have, has me scrutinizing my mast, boom and standing rig components ahead of plan which has me asking. I'll try to add some pics so you can see what I'm seeing and questioning.
****what size was the old boat that you would get the donor materials from - rigging components for a - say a Hunter 27 would be too heavy of gear for your boat. I recently bought a used mast and when I got it home I discovered that it was a battleship mast! Not really but the rigging and the mast were far far heavier than the Mac gear and I had to strip off everything to lighten it up. All of the big heavy stainless cables had to go along with all of the stainless fittings. I put on the gear from the venture including the stays and shrouds. Ventures are very light boats with light rigging..*****
Most of the shrouds I have are measuring as 1/8" dia (0.126" on my digital caliper) but the port lower shroud is coated with some kind of plastic and measures 0.176" dia -- suspecting this is a PO sub/emergency fix.
Q1: Is it reasonable to believe it should also be a 1/8" shroud as well ?
The forestay received with the boat also measures as 1/8" dia but looks like it was cannibalized from a clothesline as it's clearly not SS and the hex-nutted cable clamps are thoroughly rusted. There's also about a 4 feet of excess cable I'll call a "wild tail" that serves no apparent purpose.
***Mine measure: forestay and backstay= 1/8, all shrouds= 5/32. That backstay of yours is massive. My guess is that both your fore and back stays have been replaced overs the years on the cheap. Where exactly is this 4 feet of excess cable?***
Q2: Can anybody confirm that the correct diameter for the forestay is 1/8" ?
The backstay received measures as 0.191" dia with my caliper -- seems much larger than I expected.
***see Q1***
Q3: Again, can anyone tell me what the appropriate diameter for a backstay should be for my V21 ?
Some of the stays/shrouds I ave appear to be in decent shape, others definately need replacing.
***see also Q1. If the cable is questionable at all replace it. You do not want your mast to come down.***
Q4: Does anybody know of a source for what the "factory" lengths/specs of shrouds and stays should be if I should want to order replacements? I looked on a site called Maury Pro Racing that as a "get a free instant quote" tool that you put your boat make model in but it prompts for the "measured length of your existing component with turnbuckle half open". This is problematic on a couple of fronts. None of the shrouds/stays I have use turnbuckles, instead they're fitted with the multi-hole stay adjusters that MacGregor suggests are better than turnbuckles. Secondly, some of my components have enough bends and kinks in them that I'm unable to pull straight enough to trust any measurement I get.
***No turn buckle on the forestay??? Got a picture???
How I measured: Put mast up make it all plumb and level with boat as close as possible with all the connectors at MIDRANGE (If they are miss-sized they might be too loose/too tight). Use good judgement. Once everything looks to be at neutral mark all shrouds at the bottoms - the idea is to know the "bearing to bearing" distance on the cable. For you that would probably be the inside end of the cable loop/thimble. Take mast down disconnect all cables at bottom and stretch them out tight (use assistant) and measure with tape measure bearing to bearing or marks. Order that bearing to bearing lengths (thimble to thimble loop edges). Adjustments in the connectors can make up for "small" errors. ***
Q3: Can anybody supply me a picture of what a "factory" masthead looks like? I can tell that something at the top of my existing mast has broken but I can't really tell what it was. (See pics attatched)
***Someone with a V21 rigged same as yours would have to post a pic - yours is a masthead rig. V21's were all over the place in types of rig from the factory. The part that looks broken is the original main halyard cheek block - the sheave is gone. That's why someone hung the double block from your backstay tang, Also your Jib block is not original (thats a good thing).****
YMMV