Dismasted this past weekend.

[Catigale]

I guess I'll just have to disagree on this one and go with the guy that makes his living doing this and like I said if we ever have a problem I'll be sure and post. Still love ya and agree with 99% of your posts

Ill shoot for 99.9% next year.....

[delevi]

I have to back Catigale on this. Different thickness wire requires different tension, which is why guidelines are % breaking strength which varies with wire thickness. What's tight on 1/8" may not be tight enough on 5/32" etc. From a guy who messed with rig tension to the point of embarassment (Yes, I'm a bit obsessive;) here is what I found:
15-20% breaking strength on a Mac is just unrealistic unless you keep your boat rigged all the time. 20% is extreme and probably too much for a Mac. Keep in mind that this is static load, before the wind ever hits the sails and Mac rigging is on the minimal side, especially the 1/8" headstay. At one point I had the upper shrouds around 650 lbs. Pinning the forestay was extremely difficult. I feared the mast raiser would snap. As far as reaching the appropriate tension; the best option if you don't want to convert to turnbuckles is to take the load off with the mast raising pole and make adjustments while the rigging is slack. This takes time as you have to slack, adjust, re-tension, re-fasten headstay, measure tension and do it all over again until you get the numbers where you want them. Turnbuckles are ideal, but you will end up replacing all your standing rigging and secure them nicely for trailering, otherwise they'll bang against the sides of the hull. All the tools available that I used for the Mac stay adjusters just didn't work well enough when the tension gets near the desired level. As far as proper headstay tension for pointing; forget about it. When I had the shrouds at 650 lbs, I still had plenty of headstay sag sailing upwind. Before buying my C380, I looked at a few hunters in the 35+ foot range. Very similar rig to the Mac w/o backstay. I could wiggle the headstay on those Hunters by hand and they had ample give. If pointing high is important to you, the only way you will substantially reduce headstay sag is by installing either a backstay or running backstays. Both systems have their inherent problems which I won't go into, unless someone is interested, in which case, reply and I'll share.

Cheers,
Leon
Akula-SF

[vizwhiz]

Sorry to hear about the dismasting...never a good thing!

Back to an earlier part of the thread please...
My spreaders (95 S) are the swinging type, which I'm assuming mean that they are just pinned with a vertical bolt at the inner end and can swing back-and-forth. (Mine swing back-and-forth when I'm putting the mast up and are not "fixed".)
If this is not good, and I need to upgrade, are the new brackets/sockets available on BWY for all boats? Was this a problem only for the X boats?
And for those who have the older boats, did everyone upgrade theirs, or are there some of you who still have the swinging spreaders and have not had problems?

[seahouse]

(Sorry Viz- please excuse my timing - hopefully we can leapfrog the thread topics concurrently without interference).

Not sure I understand the problem regarding the forestay tension for the two different diameters of wire. Sorry if I’ve got it wrong – I’m begging indulgence, I’d like to get it right.

The length of the forestay is chosen to provide the desired mast rake angle. If a furler foil is present, it’s often not even practical to measure the forestay tension.

With aft-swept spreaders, because of the geometry of the construction and the pairing of the forces, the tension that the top shrouds are set to dictates the tension on the forestay. If the tension on the top shrouds is set to, say 20% of breaking load (and the presence of aft-swept spreaders does dictate the highest tensions), then that is what dictates the tension on the forestay, regardless of the diameter of the forestay wire.

I would have to guess that the geometry of the design as built by the factory would have to allow the tensions for both to be adjusted within the required bounds (15 to 20%) otherwise, it would not be possible to properly balance the tensions on both the top shrouds and forestays at the same time.

So is one school of thought that using a larger diameter wire on the forestay is verboten because it would not be possible to attain the correct range of elongation for it? That it is too inelastic to be placed in concert (or opposition) with the smaller diameter top shrouds? It is logical that tension is tension, reagrdless of its source, but the tension provided by a smaller diameter wire is "springier", and more able to adapt to movement and to absorb shock.

I’m looking for the reasoning and logical line of thought that leads up to the conclusions, and not just the (conflicting) conclusions. Anybody understand how this is derived? Thanks in advance.

- Brian.

[delevi]

OK Brian. I will attempt to indulge. First, I lack degrees in physics and engineering, but I haven't let that stop me in the past
It is true that tension is tension, however, tension will not act the same on different diameter wire. If you take a guitar string and put 20 lbs tension on it, it will be very tight. If you take a 1/4 inch cable and put the same 20 lbs tension on it, it will be sloppy and easy to deflect and certainly won't be adequate for sailing loads. If you look at a Loos Gauge, it will have different pound loads on the legend scale as it corresponds to the numbers on the gauge. The gauge works by measuring deflection. If you measure (deflect) a 5/32" cable and get a number of 40 for example; that #40 will translate to a certain amount of load defined on the gauge. If you got 40 on 1/8" cable, that would translate to a much higher load. The gauge legend has a table for different cable thickness so the same numbers correspond to different amounts of load depending on cable diameter. For a more scientific answer, someone else should chime in. As for the triangle of upper shrouds to forestay, you are absolutely right. Forestay sets rake and upper shrouds control its tension. That said, the configuration has limitations based on angle (35% sweep of the spreaders,) distance form the point of effort (length of spreaders) and leverage-the bottom line. You would need to apply a massive load to the upper shrouds to get forestay tension equivalent to what you would attain using a backstay with much less force. The backstay has a more advantageous angle, and leveraged much better to do that job. So although the tripod setup is sound structurally and will do the job, it will never enable the same headstay tension as a backstay would.

Leon

[Catigale]

Trying to summarise my view on this...

It is my belief that the vast majority of failures of forestays on Macs are caused by rigging being too loose, causing failure by fatigue. I don't recall a single instance of tensile failure, where the rigging breaks ue to excessive static load.

Moving the rigging up in size does not protect you from this, other than the benefit that larger wire will take longer to fatigue fail...but I don't think this benefit is large.

If you aren't careful when you upsize to add tension, you end up Worse than smaller wire with correct tension.

My guess is guys like Sum and Leon know their stuff and will tension accordingly. I'm a bit disturbed by a rigging guy who thinks tension and wire size aren't related.....

The definite path to avoid is

Hmmm..I have to replace my forestay, I'll go up one size so it's stronger. You have to add tension, of approx 50%, as noted above...you will then have a stronger and safer rig.

[Catigale]

Roger may have chosen the 1/8 forestay (different from the rest of the standing rigging) for his exact reason: strong enough tensile strength, but light enough that it can easily be pinned at the appropriate tension to avoid fatigue failure

[Ixneigh]

I used 7x19 on my headstay for this reason. Plus a size up. I treat this boat like a wooden boat. I think rigging that is too tight puts a lot of static strain on the boat and fittings. This is a lightly built boat. My mast is up most of the time.
The head stay should be checked by some experienced sailor in absence of a gage to see that excessive sag does not occurre when sailing. Top and bottom of all wires should have either toggles or enough play so that the wire where it comes out of the sleeve is not bending. If the head stay looks good and the lee shrouds are not loose when sailing, I think everything should be ok.
The rigging on trailor sailors gets a lot of abuse. I mangled the lower shroud eye fitting the first time I put the mast up because I did not notice it was not lying fair with the shroud adjuster.

[Divecoz]

Roger is NO DUMMY... No Doubt he doesn't want Bad Press about his boats, so he has designed and built them to be .. Safe , Cost Effective and to Last..
That's a Pretty big order if you also, want to be in business forever.. BTW He has outlasted most of the competition.

Roger may have chosen the 1/8 forestay (different from the rest of the standing rigging) for his exact reason: strong enough tensile strength, but light enough that it can easily be pinned at the appropriate tension to avoid fatigue failure

[Sumner]

........I’m looking for the reasoning and logical line of thought that leads up to the conclusions, and not just the (conflicting) conclusions. Anybody understand how this is derived? Thanks in advance. - Brian.

You have it all figured right in my mind.

First can anyone tell me why our 5/32 shrouds aren't breaking? Anyone on here have them tensioned to 500#?

The purpose of the rigging is to first hold the mast up, but also appose the loads when sailing. When sailing the lee shroud can go almost slack or slack in the case of a boat without proper tension. Here is a quote from the loos site...

Contrary to popular thought, a slack rig is more punishing on a hull than a properly adjusted, tight rig. Insufficient tension will not reduce the loads transmitted in the hull. Slack rigging will punish the spar and rigging needlessly by allowing excessive movement, chafe and shock loading. Modern fiberglass hulls should not be damaged by a properly adjusted, tight rig.

So we want the rig tension high enough that the lee shroud will not go slack and promote mast pumping and the stress on everything that creates. Since we have fractional rigged boats the forestay sets the rake but also opposes the shrouds, especially the upper shroud that attaches at the same point the forestay does at the mast. The lower shroud is use to straighten the mast and give support also. Most people's boats probably have the lower tensioned less than the top (ours isn't). There again they are 5/32 wire and are not breaking. So why is it that if none of the shrouds are breaking that it is dangerous to go to 5/32 wire on the forestay if one wants? I've been the first to admit that even though we have done it that I don't think 1/8 is dangerous if it is checked and cared for.

Almost all of the forestay breaks that I've heard of or seen pictures of show the break at or near the swaged sleeves at the thimble. They are happening due to bending at that location and the condition is worsened by using a furler without toggles at both ends, especially the top.

So what we should be talking about is keeping enough tension in the rig to avoid slack lee shrouds and to use toggles to avoid bending and breaking of the forestay near the ends by the swaged on fittings. Also replace rigging more often and not implying that a 5/32 forestay is creating a dangerous situation unless these are failing and I've seen no evidence of that.

Also you can check tension on a forestay inside of a furler if you have a Johnson lever or turnbuckle. Check the tension without the foil on the forestay first with the Johnson lever in place using the turnbuckle. Now mark the turnbuckle and put the furler back on and the turnbuckle to where it was and just use the Johnson Lever in the future. You could do the same with the turnbuckle and mark it for future reference. You are sliding the furler drum up and tightening the turnbuckle to tension the rig after pinning the forestay aren't you? A pain that probably a lot of people are not doing and I'll bet that sooner or later that is going to present a problem. Get a Johnson Lever and don't look back,

Sum

===================================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

[macr]

Found an article to share with information on this topic...

"I have a MacGregor 26x, and I can't tell you how much the proper tune helped my boat this year. I have done some reading on the subject, watched Brion Toss's video (http://www.briontoss.com) and have generally become familiar with the subject. By the way, I highly recommend Brion's video. While a number of the comments here will be specific to my MacGregor 26x, the basic comments will apply to most trailerable fractional rigged sailboats. The procedure is similar for masthead rigs, but not quite the same, as the spreaders may not provide a bending force on the mast, instead relying on the backstay to provide the mast bend.

One question that is commonly asked is "Why bother tuning?" "Stainless rigging doesn't stretch, right?" and finally, "Gee, it looks tight - it must be OK, right?"

Well, stainless cables DO stretch. Not much once they reach a reasonable tension, but nonetheless, stretch does occur. Also keep in mind that there is some initial stretch that occurs because of the cables are made of stainless wires that are wrapped around each other - in other words, initial tension removes the "slop" from with wire itself and the wire bundling. Not to mention, on many smaller boats, the rigging is attached to the mast and chainplates using simple loops, thimbles and crimp connectors, meaning you need to get the slop out of the connections before the rigging will be tensioned correctly.

Let's start with the caveats - each rig is different. Some basic ideas apply to all sailboats, but nothing is carved in stone. And, unfortunately, many small boat owner's manuals just aren't very specific on this subject of tuning. That leads you to either learn it from what you can find to read (also rather limited), finding other owners of your boat (who may know even less than you, or worse yet, give you wrong information), or hiring a professional, and hope to watch how its done.

Keep in mind, as Brion Toss says, tuning a rig is about "relationships". Each time you tension one shroud, you change the tensions on the other shrouds. Each shroud has a specific purpose or purposes, which will become evident once you understand the basics, then spend some time looking at the shrouds and thinking about those "relationships". Keep in mind this is a primer, not an authoritative work. This should give you some basic tools, but then also get you thinking about how to apply these principles to your boat.

Lets start with the basics of wire tension:

First, overtensioning is bad (here's a case where more is NOT better). If your rigging is too tight, you will wear out your rig faster, and cause some nasty mast compression forces to build up. On deck-stepped masts, you can even do damage to your deck, especially if there is no compression post inside the cabin to support the mast compression forces. But on the other hand, undertensioning as bad, if not worse than overtensioning. If your rigging is too loose, the mast will slop side-to-side from waves, sudden bursts of wind, etc., causing tensions to suddenly rise in the rig. This is called "shock loading". These shock loads can end up being higher than the designed loads, either weakening the rig or breaking it outright. Think of it this way - you're pulling a car out of a ditch - if the rope is loose and you get to 10 mph before you hit the end of the rope, BANG! Something's going to break - it might be the rope, it might be the car - the same thing applies here. In addition, a loose rig will allow the mast to tip off leeward, increasing the wind force downward (think about it for a moment, it will make sense) and therefore increasing heel. As the heel increases, the weather helm increases. In the end, you have a boat that doesn't want to point. I will tell you that with our rig undertensioned, I found one of our thimbles on the lower shrouds cracked all the way through from shock loading - obviously not a good thing?

The initial tension required to take most of the stretch out of a shroud is about, IMHO, 5% of the breaking strength of the wire, or in the case of my 26x, about 165 lbs. of tension. You will be probably be surprised at just how much tension that really is. I suggest, however, that you get a gauge to do this - it is extremely common for people with regular turnbuckles to over-tension the rigging. It is also very common to under-tension the rig as well.

Tuning the rig - the steps involved:

As for the tuning, plan on a couple hours worth of tinkering, especially if you don't have true turnbuckles on your stays (I just have those slot adjuster thingies that MacGregor uses - this makes the job kind of a pain). Once you're done, however, you shouldn't need to do it again - assuming you mark the turnbuckles and adjusters for the correct position.

First, check your owners manual and try to find out as much as possible about your particular boat. While these comments are guidelines, each boat can be a little different, so relying on any one source of information (even the manual, if it is vague or unspecific about tuning) can be dangerous. For those of you with MacGregor 26xs, I have found that the mast rake should be about 2 degrees and the mast bend should be about 1-2" if you have an adjustable backstay. You will probably note that this contradicts the manual - its just what I found works for me, reducing weather helm and increasing pointing ability.

With the mast down, measure the upper, then the lower shrouds for equal length side-to-side. Adjust the shrouds to equal length if they are not there already. If your mast is already stepped, you can measure the shrouds with a tape measure. Raise the end of the tape measure on a halyard and measure to each chainplate for equal length. If not equal length, adjust the shrouds accordingly. This is your starting point for a straight mast.

Now with your mast up and all the shrouds and stays loose (but not entirely floppy), adjust the forestay to get the amount of mast rake you have in mind. Reducing mast rake (tilting the mast more towards vertical) will reduce weather helm or increase lee helm. Increasing mast rake (tipping the top of the mast more towards the rear of the boat) will increase weather helm or reduce lee helm. In the end, you will want a little weather helm. Once adjusted, make a mark on the forestay turnbuckle so you can re-set it to that rake consistently.

Now remember, rake is the angle of the mast to the WATER, not to the deck or the bootstripe, unless your bootstripe or waterline is truly level with the water. With the MacGregor 26x, so many of us have different motors (including some up to a whopping 90 hp!) that loading of the boat can differ substantially, effectively changing the mast rake, even though the angle to the boot stripe is identical. Therefore sticking to the "specs" may not get you the handling you want.

Once you have the mast rake set for the desired angle, tighten the upper shrouds EQUALLY ON EACH SIDE (in SMALL increments) and tighten the backstay to induce mast bend to the desired amount. As you tighten the shrouds and backstay, sight up the mast to make sure it is straight laterally (side-to-side) and doesn't tip off one way or the other. Do this often (after each set of adjustments, i.e. adjust port upper shroud, then starboard upper shroud, & sight up the mast). Some people recommend tightening the backstay to get the bend, then tightening the upper shrouds to maintain that bend, but either way, you want to tighten just enough to get the bend you want. With fractional rigged boats with backswept spreaders, the upper shrouds induce the mast bend. The lower shrouds limit the bend, in effect "freezing" the amount of mast bend and keeping the mast from "pumping" over waves and in puffs. Also, double check your mast bend, and make sure it is a nice smooth bend, with no s-shapes, etc. Ideally, you will keep adjusting first the upper shrouds, then the lower shrouds. You will keep going until you have tension on your upper stays of about 15% of the breaking strength of the shrouds (check a West Marine or other catalog for specs on wire) and about 10% of the breaking strength of the shrouds on the lowers. All this while maintaining the proper mast bend, rake, and lateral alignment of course.

Keep in mind that on most fractional rigged boats, an adjustable backstay will only bend the top of the mast, so don't rely on it for all of your mast bend. Instead, induce some "static" bend using the rigging, and use the adjustable backstay to get a little additional bend when needed. I have heard it is possible to actually bend (permanently) the mast if you give the adjustable backstay a gorilla pull.

At this point, you may be having to back off the forestay turnbuckle, and maybe even releasing the forestay entirely to make the adjustments on the shrouds if you have those slot/hole adjuster thingies (love those nautical terms!) rather than true turnbuckles.

Remember, once you've got it right, and you double check it after your first few sails, its done - no more messing with it. So if you can borrow a gauge, rather than buying one, so much the better.

The MacGregor manual and many other trailerable sailboat manuals are extremely vague on the issue of correct rig tension. I have asked a master rigger about the correct tensions, and it seems that MOST builders design their boats and rigging to be tensioned according to the tension "rules" I've noted above.

I do NOT know for certain that the 26x (or any other boat) is "designed" for this tension, but when you read the information available, it seems most manuals seem to support these conclusions. Any way about it, if your rig is undertensioned to the point that you get "shock loading" over waves and in puffs, this results in much higher temporary loads on the shrouds, chainplates and other tackle than would occur if it were properly tuned in the first place.

By the way a 10% of breaking strength load on the shrouds will make a very low "musical note" when whacked. We're talking about as low as the lowest piano note, maybe lower. 15% makes a slightly higher note, but not much. On the Blue Water Yachts website, where it talks about rig tune, there's a comment that the rig shouldn't be "so tight as to play music", and I think the 10% - 15% rule would still qualify.

Once you have all this done, you've completed your dockside tune. Go sailing. The lee shrouds should loosen a little in 15 - 20 knot winds, but not go slack. The top of the mast shouldn't fall off to weather, and should look straight in these winds. It is possible that the top might point toward the wind in very light winds, but that is OK, as long as the mast is straight in 15 knot winds. The boat should point well. It should have a little weather helm (my 26x has none - the steering with a big motor attached is too stiff to feel weather helm). The mast should not "pump" forward when hitting waves. The boat should not heel excessively, and it should generally be well behaved.

When is "close" good enough? It all depends on how "close" is close (no, we are not talking about "what the definition of "is" is). If you asked me "is 5% tension close enough for most trailer-sailors?" I'd probably say yes. But then again, I'm not an expert.

I would say, however, that if your mast is straight laterally, if it has the correct mast bend, if the lee wires do not go floppy on a close reach in 15-20 knot winds, you're rig is probably tuned acceptably UNLESS the rig is over tensioned. As a test, "whack" on your wires to make sure you're getting a LOW note and that the lowers are at a slightly lower note than the uppers, and that they are the same "note" side to side. Lots of ifs, I know.

This completes the primer on rig tuning. Lots to know, but lots to gain. In closing, racers will generally keep their rigs tighter than cruisers, but may also get a correspondingly shorter life from their rig. Each boat is different, so study up. It always helps, in my opinion, to talk to a rigger if you can find one, or get a rig tuning video. In closing, the tuning of your rig will have more impact on your speed and handling under sail than anything else except sail trim, yet great sail trim still won't offset the negative impact of a bad rig tune.

I hope this helps you enjoy your sailing to its fullest.

Fair winds,

Bruce "

http://www.macgregorsailors.com/article ... racrig.php

[delevi]

Good points by Summer & Catigale. I change to 5/32 forestay and found it was more difficult to keep tight. One point that hasn't been brought up is jib halyard tension. This can go a long way in reducing forestay sag, but unfortunately, not controllable with a CDI furler. For those with hank-on sails, can be an interesting experiment. Crank up the jib halyard tension with a winch and sail close hauled and observe forestay sag. Drop tension and see what happens. For roller furling, the only way to take advantage is to upgrade to a Schaeffer or Harken which use true halyrards, as the CDI only compresses itself within the foil as it is not attached to the mast.

Leon

[DaveB]

Sumner,
Main reason I went to a 5/32 headstay is the wire is much more ridgid than the 1/8 thus haveing a less bend in it when beating to windward giving the sail much better trim.
I also like the safty margin of fatige that one might not notice.
When I reriged my Alberg 35 for around world cruise all standing rigging was one size up and after spending 3 days in 40 ft. seas beating to St Thomas I was glad I did with no rigging problems at all.
I have always been a person that thinks, beter to be safe than sorry.
The Mac. Hull flexes as there are no bulkheads, how do you tune that.
So I am in agreement with you and I never heard of a Mac. dismasting because of the 5/32 wire.
I tune a Mac. from 45 years of Sailing, don't use gauges and it's just sea knowledge sence.
Dave

SW Florida Sailing Red Neck.

........I’m looking for the reasoning and logical line of thought that leads up to the conclusions, and not just the (conflicting) conclusions. Anybody understand how this is derived? Thanks in advance. - Brian.

You have it all figured right in my mind.

First can anyone tell me why our 5/32 shrouds aren't breaking? Anyone on here have them tensioned to 500#?

The purpose of the rigging is to first hold the mast up, but also appose the loads when sailing. When sailing the lee shroud can go almost slack or slack in the case of a boat without proper tension. Here is a quote from the loos site...

Contrary to popular thought, a slack rig is more punishing on a hull than a properly adjusted, tight rig. Insufficient tension will not reduce the loads transmitted in the hull. Slack rigging will punish the spar and rigging needlessly by allowing excessive movement, chafe and shock loading. Modern fiberglass hulls should not be damaged by a properly adjusted, tight rig.

So we want the rig tension high enough that the lee shroud will not go slack and promote mast pumping and the stress on everything that creates. Since we have fractional rigged boats the forestay sets the rake but also opposes the shrouds, especially the upper shroud that attaches at the same point the forestay does at the mast. The lower shroud is use to straighten the mast and give support also. Most people's boats probably have the lower tensioned less than the top (ours isn't). There again they are 5/32 wire and are not breaking. So why is it that if none of the shrouds are breaking that it is dangerous to go to 5/32 wire on the forestay if one wants? I've been the first to admit that even though we have done it that I don't think 1/8 is dangerous if it is checked and cared for.

Almost all of the forestay breaks that I've heard of or seen pictures of show the break at or near the swaged sleeves at the thimble. They are happening due to bending at that location and the condition is worsened by using a furler without toggles at both ends, especially the top.

So what we should be talking about is keeping enough tension in the rig to avoid slack lee shrouds and to use toggles to avoid bending and breaking of the forestay near the ends by the swaged on fittings. Also replace rigging more often and not implying that a 5/32 forestay is creating a dangerous situation unless these are failing and I've seen no evidence of that.

Also you can check tension on a forestay inside of a furler if you have a Johnson lever or turnbuckle. Check the tension without the foil on the forestay first with the Johnson lever in place using the turnbuckle. Now mark the turnbuckle and put the furler back on and the turnbuckle to where it was and just use the Johnson Lever in the future. You could do the same with the turnbuckle and mark it for future reference. You are sliding the furler drum up and tightening the turnbuckle to tension the rig after pinning the forestay aren't you? A pain that probably a lot of people are not doing and I'll bet that sooner or later that is going to present a problem. Get a Johnson Lever and don't look back,

Sum

===================================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

[Highlander]

Three forestays 5/32 , third set of masthead shrouds, second set of upper spreaders , rotating backstay on a arch mounted traveller I have no Issue's keeping my forestays tight


J

[Sumner]

Three forestays 5/32 , third set of masthead shrouds, second set of upper spreaders , rotating backstay on a arch mounted traveller I have no Issue's keeping my forestays tight


J

I see that picture and feel that Ruth and I are such wimps . If I tried that I might loose a sailing partner. I would like to sneak out one day on someone else's boat and sail like that .

.............and then there is Dave...

....I tune a Mac. from 45 years of Sailing, don't use gauges and it's just sea knowledge sense.
Dave

I'll have to live to about 110 to be able to say that , don't think that is going to happen ,

Sum

===================================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links