Halyard Shackle

[NiceAft]

I took a look at the halyard shackle for the main and I am amazed at how bent, warped, mangled it is. Definitely time to replace, but with what pin size 3/16, 1/4, 5/16 I don't have the standard Doyle sail. I have a musclehead. That may place excessive stress on the factory supplied shackle.
(For those who are new to the board and may not be aware, click on photo to enlarge)

I'm thinking that overkill is not a bad idea for something so vital. I've never heard of any Mac's that had a failure there, but I don't wish to be the first
I am leaning towards this one (5/16 pin). http://www.westmarine.com/webapp/wcs/st ... J-t4IauVq0

Any engineers out there in Mac land should feel free to chirp in with technical advice. Here are the choices from West Marine. http://www.westmarine.com/webapp/wcs/st ... mpleSearch

Ray

[c130king]

I don't even use a shackle. Just a bowline tied through the headboard. Nothing to bend or mangle...or break or fail.

Just a thought.

Cheers,
Jim

[bscott]

I don't use stamped shackles in high load twisting apps. A forged shackle is more resistant to twisting. Whichard makes a captive pin D shackle that you might consider.

Bob

[NiceAft]

Thanks for responding fellas.

My fear Jim, is that chafing on the bowline will create a greater probability of failure than any such rubbing by a shackle designed to do the job.

Bob, I did not look to see if any of the Whichard shackles shown are forged or stamped. I will look.


Ray

[mastreb]

The stamped shackles that come with the boat are way too lightwieght imho--all of mine became twisted after the first few sails on the mainsail, vang, and halyard.

The problem I have with forged shackles for the halyard is that they don't have a separate eye for the bowline knot, and so can fall out if the key pin is left open. You might consider going to a forged jaw swivel shackle to prevent twisting from damaging the shackle but those are a bit pricier.

A bowline knot will work just fine--it's what holds your shackle fast to the halyard anyway. The reason to use a shackle is for ease of disconnecting the mainsail when rigging to trailer. If you stay mast up I'd save the $20 and just tie the knot when necessary.

[RobertB]

I am still updating from the cheap factory shackles as the budget allows.

So far, the following allows me to rig fairly quickly:
I use a bowline directly on the main headboard as Jim does. I can tie a bowline as quick as engage a shackle.
I use small brass snap shackles on the mast raiser at the mast and the main sheet to the traveler.
I use the cheap stamped quick release shackles that were delivered with the boat for the mast raiser mini stays. I leave these attached to the stantions, held in place with small wire ties thru the holes in the shackles. I would like to replace these with good snap shackles but would have to rework the crimps in the mini stays to attach. I may look into using dyneema instead of wire for the mini stays.
Last, I keep the tack of the sail attached directly to the boom using a twisted shackle and a bolt. Using sail slugs, I keep the main on the boom and store suspended from the ceiling in the main cabin when not rigged. I use a clevis at the gooseneck instead of a bolt.
I use the oversize clevis at the bow fitting for the roller furler and clevis pins for the mast and mast raiser at the tabernacle.

End result, only need tools when rigging to open the mast gate (screwdriver) and unlock the rudders (two 9/16 inch wrenches).

[Terry]

The prices of those halyard shackles are way off the charts, no way I paid or ever would pay that kind of money for something so simple. I do have a heavy duty SS captive D shackle better than those WM ones mentioned and I did not pay that much for them, I have a few of them. I would not waste my money on those cheap stamped ones that appear to be forged from aluminum. Go to a marine store in person and have a look around, you should find a good high quality SS halyard shackle for a reasonable price like under $20.00. I also have the Musclehead sail and it is much heavier than the OEM Doyle and will easily bend those stupid cheap shackles out of shape over time. I also have a tiny liitle SS shakle that stays with the top slug when I fold the sail up, you know that last shackle at the top of the headboard that has to be dis-connected in order to fold the headboard down. I use a easy undo SS shackle for it and I also have a big SS halyard shackle to hold the headboard up while I connect that tiny shackle from the slug to the top hole in the headbaord. It is a finnicky process but I do it every time. The big halyard shackle gets connected to the mast reefing hook when not connected to the sail, I have other places to hook it too but I would definately not want to be always looking for somewhere to tie with a bowline, when a shackle is so much easier.

[NiceAft]

Pictures would be nice to see, and also easier to comprehend. I believe I understand your system, but a photo would help.

Ray

[mastreb]

I am still updating from the cheap factory shackles as the budget allows.

So far, the following allows me to rig fairly quickly:
I use a bowline directly on the main headboard as Jim does. I can tie a bowline as quick as engage a shackle.
I use small brass snap shackles on the mast raiser at the mast and the main sheet to the traveler.
I use the cheap stamped quick release shackles that were delivered with the boat for the mast raiser mini stays. I leave these attached to the stantions, held in place with small wire ties thru the holes in the shackles. I would like to replace these with good snap shackles but would have to rework the crimps in the mini stays to attach. I may look into using dyneema instead of wire for the mini stays.
Last, I keep the tack of the sail attached directly to the boom using a twisted shackle and a bolt. Using sail slugs, I keep the main on the boom and store suspended from the ceiling in the main cabin when not rigged. I use a clevis at the gooseneck instead of a bolt.
I use the oversize clevis at the bow fitting for the roller furler and clevis pins for the mast and mast raiser at the tabernacle.

End result, only need tools when rigging to open the mast gate (screwdriver) and unlock the rudders (two 9/16 inch wrenches).

I'm completely tool-less: No mast gate, don't lock the rudders, and I use the BWY quick-pin for the mast step.

I'd lock the rudders for a cross country trip, but for two hours or less I tie a pretty good double cleat knot.

I do question why people don't like the bolt-rope. My last boat had slugs in the track and a mast gate, and I never liked it. I see the bolt rope as a big improvement and it has better aerodynamics.

Why the love of slugs and hate of boltrope? What am I missing?

[Judy B]

I took a look at the halyard shackle for the main and I am amazed at how bent, warped, mangled it is. Definitely time to replace, but with what pin size 3/16, 1/4, 5/16 I don't have the standard Doyle sail. I have a musclehead. That may place excessive stress on the factory supplied shackle.
(For those who are new to the board and may not be aware, click on photo to enlarge)

I'm thinking that overkill is not a bad idea for something so vital. I've never heard of any Mac's that had a failure there, but I don't wish to be the first
I am leaning towards this one (5/16 pin). http://www.westmarine.com/webapp/wcs/st ... J-t4IauVq0

Any engineers out there in Mac land should feel free to chirp in with technical advice. Here are the choices from West Marine. http://www.westmarine.com/webapp/wcs/st ... mpleSearch

Ray

Hi Ray,

I'm not an engineer, I'm a sailmaker. I'm passingly familiar with the physics of sailboats.

The maximum load on any rigging on a boat is determined by the righting moment , not the size of the mainsail. A "stiff" boat loads the rigging and hardware more than a "tender" boat does. The sail size does not determine maximum load. When a naval architect designs rig components, all they need to know is the righting moment (the measure of how much the boat resists heeling)

When your boat is heeling as much as it it, the force on the mainsail halyard shackle is the same as any other MacM, whether the mainsail is a square top or double reefed. With the possible exception of the

if the shackle got bent, it's probably not because it's too flimsey. It's probably because of the way it's aligned to the load. If it's aligned to take the load straight-on, it'll be fine. It's almost certainly getting loaded sideways rather than straight-on. In rigging parlance, we call that a "bad lead".

The halyard load on that shackle is, at most, a few hundred pounds. Any of the shackles you referenced will handle that load safely, if it's aligned straight-on.

Hope this help you to eliminate the problem, rather than use brute force to cover it up.

Fair winds,
Judy B
Sailmaker

[Judy B]

I do question why people don't like the bolt-rope. My last boat had slugs in the track and a mast gate, and I never liked it. I see the bolt rope as a big improvement and it has better aerodynamics.

Why the love of slugs and hate of boltrope? What am I missing?

There is no question that the world's most competitve racers need the aerodynamic advantage of the bolt rope to beat their competitors. A sail with a bolt rope creates about 1% better lift-to-drag ratios (or up to 2% better, depending on the circumstances, the analysis, and the author.)

But most cruising sailors value convenience and safety more than aerodynamics. Cruisers often use topping lifts, lazy jacks, external halyards, etc. Racers never do. Racers NEVER put an ounce of extra weight aloft, because it reduces the righting moment of the boat and slows it down.

Despite the boltrope's aerodynamic superiority, I personally prefer slides over a boltrope. I sail on a wide variety of boats, with both slides and boltropes, and for cruising and ease of use, I'd rather have slides.

My perspective is that slides increase my safety margins on the boat. I sail in a place where we reef regularly and where it's too rough to go to the mast when you're short handed or on a small boat. because after I feed the slides into the mast, I can I can raise and lower the sail in any condition, at any time, without needing to go to the mast.

And, I personlly don't have the patience to put up with oldfashioned mastgates on a trailerable boat, since I'd have to spend time fussing with them every time I wanted to bend the mainsail on. Mast gates are a "nice", but they aren't necessary, for reefing or raising or lowering the mainsail. I don't have them on either of my own boats, nor do the owners of the other boats I sail have them usually. They are absolutely NOT necessary for reefing if you set up your rigging appropriately. But that's a whole 'nother topic. Any competent sailmaker or rigger can show you how to setup your boat so you don't need mastgates to reef quickly and safely.

Fair winds,
Judy B
Sailmaker

PS. I have used the terms slide and slugs interchangeably in this post, which isn't proper use of the terms. Slides come in a variety of shapes. "Slug" is a term for a slide with a barrel shape.

[Ormonddude]

Hi Ray,

I'm not an engineer, I'm a sailmaker. I'm passingly familiar with the physics of sailboats.

The maximum load on any rigging on a boat is determined by the righting moment , not the size of the mainsail. A "stiff" boat loads the rigging and hardware more than a "tender" boat does. The sail size does not determine maximum load. When a naval architect designs rig components, all they need to know is the righting moment (the measure of how much the boat resists heeling)

When your boat is heeling as much as it it, the force on the mainsail halyard shackle is the same as any other MacM, whether the mainsail is a square top or double reefed. With the possible exception of the

if the shackle got bent, it's probably not because it's too flimsey. It's probably because of the way it's aligned to the load. If it's aligned to take the load straight-on, it'll be fine. It's almost certainly getting loaded sideways rather than straight-on. In rigging parlance, we call that a "bad lead".

The halyard load on that shackle is, at most, a few hundred pounds. Any of the shackles you referenced will handle that load safely, if it's aligned straight-on.

Hope this help you to eliminate the problem, rather than use brute force to cover it up.

Fair winds,
Judy B
Sailmaker

Well we know from the Macgregor promo video they hold the boat over with a 125lbs at the top of the mast so that must be the healing load? or Righting Moment? (btw I use a stainless spring clasp from walmart rated at 575 lbs for my sails its fast easy and very strong I also used them for Mast Raising System) I looked for them online and they didnt turn up I will try to take picture. IMHO the mainsail is being overloaded your cranking in the main for pure heal and no added speed. Hence bending the shackle with unusable force.

[Judy B]

Well we know from the Macgregor promo video they hold the boat over with a 125lbs at the top of the mast so that must be the healing load? or Righting Moment? (btw I use a stainless spring clasp from walmart rated at 575 lbs for my sails its fast easy and very strong I also used them for Mast Raising System) I looked for them online and they didnt turn up I will try to take picture. IMHO the mainsail is being overloaded your cranking in the main for pure heal and no added speed. Hence bending the shackle with unusable force.

Disclaimer:
I'm not feeling well today, and I'm not sure I'm writing coherently at all, so if what I'm writing makes no sense, please excuse me.... I've got a hangover from the flu... my brain is really foggy right now.... but here goes:

That 125 pounds is only 1/3 of the first part of how to determine the righting moment.

1.1. If 125 pounds is the force applied at the top of the mast,
1.2. The masttop is approx 30 feet above the axis of rotation
1.3. The boat is heeling ?? degrees.

We calculate that it takes 125 pounds x 30 feet to rotate the boat ?? degrees.
that's 3750 foot pounds of torque to heel the boat ?? degrees.

If ?? degrees is where it takes the most torque to heel the boat, then that's the position at which the rigging is reaches it's largest static load.
Next, the rigger/architect/engineer, looks at the geometry of the rig, including lever arm lengths and angles, and determines how much of the load is carried by each componenent. Most rig calculations are done with after determining the righting moment for either 20 or 30 degrees. Then you multiply by safety factors to get to your final specification for each part.


.... but you don't have to go trough all that math... your rigger or sailmaker or naval architect has done it hundreds of times and come up with a set of guidelines....

The static load strain on a main halyard of a 10,000 pound, 30 foot boat is less than 500 pounds. I'd guess that the load on the Mac 26M halyard is less than 250 pounds. It's not a very stiff boat.

If you are bending the halyard shackle you have, either the shackle is made of junk metal or the rigging is mis-aligned. If it's a junk shackle, replace the bent shackle with any one of the following halyard shackles or use a knot. Any name brand shackle should do the job if the lead is fair. Any of the following halyard shackles will do for a much bigger boat than the Mac26 is.

http://www.westmarine.com/webapp/wcs/st ... KFIsYa8jRw

imo, you really should figure out where the problem is, because if you need to use a shackle sized for a boat 5 times heavier than your Mac26 M/X it to prevent bending the shackle again, you will just transfer the wear and tear to something else in the kinetic chain -- the headboard and/or slugs or somewhere else.

Base on my experience with lots of boats, I'd hazard a guess that the damage to the shackle is occuring during mast raising or during trailering or because somebody changed something else in the rig design (at the mast head??) because I can't believe the strain loads generated during sailing are causing the shackle to deform like that!!!!! I'd bet you $100 dollars that the damage is happening when the boat isn't sailing....

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
BTW, if you use TOO BIG a shackle, you conceivably could create enough slop in the alignment to misalign the shackle badly enough to create enough torque to distort it. If so, the solution isn't a bigger shackle, the answer is a smaller one that fits snugly.

When it comes to designing a sailboat hull and its rigging, something that's bigger and stronger isn't necessarily better.... frequently of times it's worse.

... that's my story and I'm stickin' to it. Dat's the truff ...ow, I'm working to hard... my brain hurts....

[mastreb]

Judy's math re: righting moment is essentially correct. The 125 lbs. is the effort at the end of a 30 (actually 35 to the point of rotation) foot lever required to overcome the righting moment. You can calculate this using sine(heel) *35 * 125 lbs, so for a 45 degree heel the righting moment is 3094 lbs. If you extend this to 60 degrees you get 3788--the righting moment increases as the boat heels, and the force incident upon the sails decreases as the boat heels. At 90 degrees, there's zero force upon the sails (because they're horizontal) and the righting moment is maximum at 4375. This is why sailboats will only blow down in extreme conditions. The point of the water ballast is to keep the center of gravity lower than the center of rotation--if it were higher, the weight of the hull adds to the turning force rather than resisting it, and the boat is guaranteed to tip over as soon as a side force is incident upon it.

Knowing this formula and how to calculate it is important for deciding things like whether or not you should go up the mast in a bosun's chair (the answer is no, you should not).

What she may not be familiar with is how flimsy the shackle you're talking about actually is. I can twist the stock shackles by hand, and completely ruined one by merely tightening my vang the first time we went out.

Replacing it with a swivel shackle will guarantee that you've never got any uncompensated twist to worry about. Or a bowline knot--a properly tied bowline has 90% of the breaking strength of the rope and that's far more than the forces endured at the halyard.

I've got a plastic bin with a locking lid that I put all my replaced hardware into, to act as injury rigging should something break. It's got everything I bought and then didn't use in it as well. I call it the rig box. It's about the size of a small shoebox, and it's surprising how often I have it out, and how much stuff it's collected over just two years.

[robbarnes1965]

Knowing this formula and how to calculate it is important for deciding things like whether or not you should go up the mast in a bosun's chair (the answer is no, you should not).

Just as an aside, this is picture of Sheri freeing a snagged halyard a little over a week ago when we were in Grenada. And no, I would not even send Sheri up the Mac mast