The Cunningham, the Halyard, and Luff Tension

By Mark Abraham · Oct 31, 2012
Halloween: We Be Jibin'

This article is part of our 2012 Halloween costume. Click here for full costume.

Let’s let you in on the sailor humor first, since not once in this video is the cunningham referred to as it sometimes is in colloquial parlance as the “smart pig.” It’s called that sometimes because the guy who invented it has a last name that is a portmanteau of…

…oh, you get it.

And, yes, sailing humor is the type of stuff that folks rich enough to own a boat find funny in between puffs of cigars and Bud Lights. But sailing humor is also how shit is often named, so it’s this weird thing where everybody crewing on a boat gets roped into making lame jokes that are little more than puns or slight observational humor. Why? Because they like sailing but probably can’t afford to own their own boat.

(And by “folks,” yes, I mean “typically older white men,” but you probably already got that since “smart pig” was just so damn clever. Speaking of which, why “smart pig”? Here are some other options:

  • crafty hog
  • witty sus
  • cerebral shoat
  • clever sow
  • astute swine
  • keen boar
  • Machiavellian porker

…or, whatever, you can put lipstick on any of ‘em and it’s still just a line. Though I do suspect if you told even an experienced sailor to “bring in the clever sow” they’d assume that was an actual thing and they just weren’t up on the regional dialect.)

(Also, don’t confuse this smart pig with the other kind of smart pig, which I didn’t know existed until I googled “smart pig” images:

A Smart Pig.

…although now I kind of wish this article was about pipeline maintenance. Also: I wonder if pipeline engineers nickname smart pigs “cunning hams.”)

(Also also, I learned from Deadwood and True Blood that pigs will eat human bodies. You shouldn’t be scared, though, that smart pigs (either kind, far as I can tell) will eat you. They don’t have mouths.)

Anyways, before we explore this video, you may be asking, “what the fuck is a cunningham?” For starters, it’s a rope, but more precisely it’s a kind of downhaul used to change the shape of a sail. The smart pig uses a second cringle in the sail right above the tack cringle (the eye right above where the boom is attached to the mast at the gooseneck). The video provides a helpful diagram:

The Cunningham Eye.

Where the arrow is pointing is where the cunningham goes. A line is run through that second eye and normally cleated to the mast. As for the other end, as the video points out, there are two systems:

Two Cunningham setups.

…after which we abandon the shitty diagrams and go to some live footage that seriously shows every nook and cranny the god damn line passes through. Let me simplify: the end of the rope that is not cleated to the mast is looped through the cringle in the sail and then (normally, especially on boats equipped for racing) run through a block below:

The block.

Now you can pull on that rope.

“Okay, but why?”

This is wind, lovingly rendered:

Angle of attack.

…cool so far?

When the cunningham is taken in it adds wrinkles to the luff of the sail. You can also do this with the halyard, but doing so might compromise the correct curve of the sail:

Roach curvature.
Roach curvature.

The halyard, since it pulls from the top, tends to flatten your sail’s roach (the outer curve of the sail), which decreases performance.

Anyways, here is the video’s photo of the effect of pulling on the cunningham, exaggerated so it is easy to see:

Exagrated tension on the Cunningham.
Michael Emerson laughs at how tight the Cunningham has been pulled.

“Yeah, okay, but why?”

Basically, adjusting the luff tension by hauling or easing on the cunningham allows you to move the draft of the sail forward or aft. In practical terms, you’re deciding on a compromise.

Points of Sail.

See that shaded red area? Easing the cunningham and moving the draft in your sail aft allows you to decrease the size of that red area and point higher into the wind (for non-sailors: you can’t sail directly into the wind, which is called “in irons,” because you stop moving; you can, however, maximize the angle closest to the wind that you can sail, called “close hauling”). Doing this, however, makes the boat much harder to steer. Check out some more stellar graphics:

Draft 1.
Draft at mid-sail.

Hauling on the cunningham and moving the draft forward lessens the angle at which you can close haul but vastly improves the control you have over the boat which, especially in heavy winds, can be helpful.

Moving draft forward.
Moving draft forward.

The reason it does that is because of this:

Ability to pinch.

…which I think is like different versions of the WWJD fish. Or two stages of rabidness in a bird. Or, okay, what’s really going on is, ignoring the physics behind this wonder drawing, that by moving the draft forward you increase the amount of room for error you have in steering the boat. In other words, in super-heavy winds if your draft is where it normally sits farther aft in the sail and you’re close hauling it’s a lot easier to move a tad too close to the wind and have your sails stall. And then you will probably lose any race you might happen to be engaging in at that moment.

So essentially it’s used for fine-tuning, depending on the circumstance, but let’s be honest: those circumstances, though they are often defined by weather, are also normally defined by how serious the crew of a given boat is about the race they’re probably in the middle of and how serious they are about just drinking and having fun. Because if it’s the latter, the chances that you’re going to tug on your cunningham decline to approximately zero. Although strangely, the chances you’re going to say “smart pig” in a funny voice go up. It’s an age old conundrum for sailors. Or at least a half-century-old one, since Briggs Cunningham only invented the thing like 50 years ago.

(Also: “Briggs Cunningham.” I feel like there’s a joke in here about turn-of-the-century rich American names and porn names.)

The best part about this instructional video is how bored the narrator seems about it all. Listen to him get to the point:

I sympathize with him, really. Learning to sail from a book or online is never going to be as interesting as actually sailing. But I have to say that this video would have been more exciting with rock music and pictures of pigs with glasses and the barest sense that the creator gave a shit about this PowerPoint presentation. Like, legibility, please:

Bad Powerpoint.

My favorite part, though, is when he says that the draft should be held forward when the skipper’s experience “is less…than it should be.” By whose estimation, I wonder? In what context? How drunk are they? I don’t really think this is a thing about experience, really, but whatevs. I found this video totally useful because so much love clearly went into making it.

Cool glasses.

That guy’s such a ham.

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