Explanations of some principles and properties of Lug-Rigs

[StevenBauer]

If some of us go back and delete some of our posts he might get a second chance at 666.

[James McMullen]

That ship has sailed, Steven. This thread is now dead to me.

[jsjpd1]

Seriously?

Good grief people! DOES NO ONE ELSE HERE HAVE A JOB?!?

I spent all day at work today, at my hard, hard job, hanging the bow 14' of a new starboard broadstrake plank of a 1947 Annapolis, either on my knees, squatting outside in the rain, or up the ladder and lying on my face in the bilge, using shores and clamps and wedges and a 4 ton hydraulic jack to try and encourage a slab of 7/8 sapele, fer chrissakes, to twist nearly 70° from the hood end into the deadrise, and all the while dealing with questionable frame ends and galvanically corroded fasteners and diesel oil and dolfinite drips and an assistant who's not all that clear on the difference between Reed & Prince vs Phillips screwdriver bits and 68 years worth of crap encrusted into the bilge right where I want to put my butt-blocks and it's freaking raining all day and my hip is still sore from the hip-flexor strain I got last week and the fricking bilge pump hoses are right in the way, and my clamps are gonna get rusty out in this rain. . .

All I wanted to do when I came home was put my feet up, maybe crack open a beer, and come visit the forum, so I can forget all my troubles with rot and cracked frames and galvanic corrosion on gigantic ancient damn powercruisers and enjoy something different. You know, surf the topics a little bit, maybe learn a few explanations for how different kinds of lugsails tension their leeches, and then, when the moment is right, maybe post a nice video of Tim's new boat--which actually uses a lugsail, of all things?

All I asked for from this thread was ONE THING! Only ONE THING! And this is the thanks I get?! ALL I WANTED WAS TO POST A VIDEO OF HAVERCHUCK FOR #666, AND THIS IS HOW YOU BETRAY ME?!?!

How the hell did you manage to get this many posts on this stupid thread in that short of a time? When I left for work this morning, everything was shaping up just fine. BUT NOW???????

I can't believe this, people! After all the many years I have devoted to carefully explaining why your boat sucks compared to mine, all of the hours spent crafting venomously snarky comments that stay just this side of the line for getting Scotted, after all the painstaking care and effort I have put into promoting the deeply flawed idea that lug-rigged open boats are the one and only truly noble form of aquatic activity. . .and now THIS?!?

GRRRRRRR! This is ALL YOUR FAULT Michael Ossi-whatever! I don't care who's actually responsible, I'm putting the blame on you! No video for you!!!

Best post of the thread.

[Steamboat]

I AM NOT A MASOCHIST! THIS IS THE LAST TIME I READ THIS THREAD! Except I did like the post with a mullet hiding under a boat!

PS Shouldn't he be writing a book and not in this post?

[Gerarddm]

I think by now all I can say is oye veh about this thread.

[Yeadon]

This is most definitely what a family of mcmullets living under your boat looks like. It's nothing to take lightly.

[jpatrick]

This is most definitely what a family of mcmullets living under your boat looks like. It's nothing to take lightly.

Whoa. Speak of the devil.
Tim, just in case I get an infestation… should I use a live trap or go for something a little more permanent?

Jeff

[P.I. Stazzer-Newt]

Gives most trouble when there are hull rot issues, if the hull is in good order it's much less of a problem,

[Chip-skiff]

What's a butt block?

Sounds quite useful.

[Daniel Noyes]

Whoa. Speak of the devil.
Tim, just in case I get an infestation… should I use a live trap or go for something a little more permanent?

Jeff

for permanent fix try upgradeing to a sloop or schooner rig and hang a long shaft kicker...
of-course if you had a dory you wouldn't have had this problem to start with!

[Yeadon]

Whoa. Speak of the devil.
Tim, just in case I get an infestation… should I use a live trap or go for something a little more permanent?

Jeff

For outdoor removal, I'd suggest laying a trap laced with Korean BBQ. I'm also suspicious that this thread might be infested with mcmullets as well. That might be the underlying issue.

[john welsford]

McMullets use them to sit on when they're infesting the space underneath boats that are up on the slip.
John Welsford

What's a butt block?

Sounds quite useful.

[Yeadon]

McMullets use them to sit on when they're infesting the space underneath boats that are up on the slip.
John Welsford

A butt block is both a noun and a verb. The noun being the item upon which one would sit. The verb being an action taken by one's butt, generally to impede or buffet another's action. I believed this was covered earlier in Explanations.

[Canoez]

A butt block is both a noun and a verb. The noun being the item upon which one would sit. The verb being an action taken by one's butt, generally to impede or buffet another's action. I believed this was covered earlier in Explanations.

Could gronicles be substituted?

[Peerie Maa]

Could gronicles be substituted?

I for one would not want to sit on a gronicle, especially one with a screw. However a well aimed pair of gronicles will most certainly buffet and hence impede.

[Yeadon]

Oh. Great point. That reminds me, you'll want to properly tension your gronicles. Has that been addressed yet on this thread? Michael, what are your thoughts on this?

[jsjpd1]

I read that a double down haul is effective for fine control of gronicle tension and can bring the yard tail up smartly. But that doesn't seem quite right.

[Yeadon]

Depends on the location of your fulcrum.

[rgthom]

If Michael's gronicles are under too much tension that could explain this whole thread....

[jsjpd1]

Regardless of the method used, it is important not to over tension gronicles.

[StevenBauer]

I hear levers are great for tensioning.

[outofthenorm]

Could gronicles be substituted?

There is no substitute for gronicles.

[Canoeyawl]

The Ossipoff gronicle tensioner, using the latest in Archimedean theory.

(The Ossipoff rig - it has a certain ring to it, no?)

[Yeadon]

Founder of the Imbalanced Lug.

[Novice091015]

Cracked-Pot quoted me:

Originally Posted by Novice091015
I don't sail. Explanations wasn't intended as a sailing-instruction. I can't advise you regarding how to adjust your sail.
For that, I refer you to John's posts on this and the previous page.

Cracked-Pot says:

You've been telling us that Explanations explains an aspect of sail adjustment

No, not really. Explanations explains some principles and means by which it’s possible for Lugs to tension luff and leech.
Explanations doesn’t give any advice on how to adjust your sail.
If you read Explanations, and then mis-adjust your sail, don’t come crying to me.

…it is unable to actually explain a real world situation as simple as this, where the sail isn't properly tensioned

The explanation is easy: You adjusted your sail all wrong. There are recent posts in this thread giving information on how to adjust it properly. Read them.
Sure, you can achieve an undesirable sail-shape, by pulling the adjustment-lines wrong.

, it [Explanations]is worthless

…for teaching you how to adjust your sail. Of course. But, that isn’t its purpose or topic, is it.
Now we get to levers, in your post. So let’s clear that matter up before we go any further:

Explanation of Levers:

(for, and in reply to, Cracked-Pot)

A lever is an extended object (usually, but not necessarily, a stick, pole, rod, bar, beam, spar or other elongated shape), pivoted at a point called a fulcrum.

A fulcrum is defined as the point about which a lever rotates. …or, in a static system, a point about which the lever would rotate if that point is pivoted to an immovable object and the moments of the effort and load, about that point, weren’t balanced.

Three forces operate on a lever:

An effort, a load, and the force exerted by the fulcrum.

It is to be emphasized that the both the effort and the load are forces exerted on the lever, and that the fulcrum, too, exerts a force on the lever. Remember Newton’s 3^rd law.

For brevity, I’ll use the term “point-force” to denote a force exerted only at one point on the lever. That’s the opposite of “distributed force”.

The fulcrum, defined as a point, then of course only exerts a point-force on the lever.

The effort and the load can be either point or distributed forces.

Where the fulcrum can be:

We’re interested in a static system, in which the lever isn’t rotating.

As Cracked-Pot (well, almost) said, in a static system, we can speak of a fulcrum at any point on the lever (it probably often or usually would be chosen as a point where a force (distributed or point) is exerted on the lever).

The choice of what point to speak of as the fulcrum depends on what forces you want to look at.

(Of course it’s meaningful to speak of a distributed force exerted on a point—on some particular point along with many other points--, because a distributed force is exerted on many points).

Note that the fulcrum is a point on the lever.

Cracked-Pot said that the fulcrum could be at Alpha-Centauri.

Nah.

Not even at Pluto :^)

The fulcrum is at a point on the lever.

Now, having clarified, for Cracked-Pot, what a lever is, we can return to his posting:

Cracked-Pot quotes me:

The levers? For one thing, both the yard and the boom are functioning as levers, with their fulcrums, respectively, at the halyard attachment point and the downhaul attachment point.

(For later reference, note that I did not say that, in a static system, that way, with those fulcrums, is the only way in which the yard and boom can be spoken of as functioning as levers. ..or that the halyard and downhaul are the only places on the levers, in a static system, which can be spoken of as fulcrums.)

Cracked-Pot replies:

You didn't answer the question

I answered the lever question, by giving an example of a way in which a spar functions as a lever.
In a static system, the point chosen to be spoken of as the fulcrum can be assumed to be pivoted to an immovable object, making it more “fixed” than the rest of the system, wherein the lever would rotate about that fulcrum if the moments of the effort and load, about that fulcrum, weren’t balanced.

Cracked-Pot replied:

, and you're wrong.

Wait a minute…Did I not answer it, or did I answer it wrong? Which is it? :^)

The boom does not function as a lever

That’s nonsense.

Cracked-Pot, you need to do a lot more studying, regarding the Balanced-Lug, and regarding levers in general.
I don’t have time to teach it to you. Come back after you’ve studied it.
(…but by that time I won’t be at the forum, and this thread will be closed.)

, because the downhaul is not a fulcrum. Tightening the downhaul will lower the entire boom, not simply rotate it.

The fulcrum doesn’t rotate a lever. It’s a point about which the lever pivots, or would pivot if that point is fixed by being pivoted to an immovable object, and if the moments of the effort and load, about that point, weren’t balanced.
Cracked-Pot, you need to read more about levers before you talk about them.
When speaking of levers, Explanations discusses a system in which the downhaul is already tightened and the system is static.

Remember that, Cracked-Pot.

Cracked-Pot continues:

Since the boom does not have a fixed point of rotation it is not acting as a lever.

Because it’s a static system, there is no rotation. But that doesn’t mean that there isn’t a lever. …as Cracked-Pot himself admits in his post.

As you said, in a static system, we have some freedom in choosing what point on the lever we speak of as the fulcrum.
The fact that, in a static system, we have some freedom regarding which point on the lever we call the fulcrum, doesn’t mean that we can’t speak of there being a fulcrum.

:^)

I address that matter at various points in this reply.
In a static system there are various points, on a lever, that could be spoken of as the fixed point about which for rotation to happen, if that point were fixed by being pivoted to an immovable object, and if the moments about that point, of the effort and load weren’t balanced.

Maybe Cracked-Pot means that there’s no unique such point. But that doesn’t mean that we can’t meaningfully and rightly speak of such a point, even though, in a static system, we have some freedom in our choice of which point to so speak of.

In the static system, the boom can be regarded as a lever with the downhaul as its fulcrum, and with the sail-foot’s distributed force, on both sides of that fulcrum, regarded as the effort and the load.

Likewise, in a static system, the yard can be regarded as a lever with its halyard attachment as its fulcrum, and with the sail-head’s distributed force, on both sides of that fulcrum, regarded as the effort and the load.

That’s what I was speaking of in the passage that Cracked-Pot quoted.

Cracked-Pot continues:

It is acting as a beam with either a distributed load (laced to the boom) or two concentrated loads (attached at tack and clew)

Rather than discussing it both ways, I’m speaking of the sail-foot laced to the boom, just as one way of discussing it. The sail-foot exerts a distributed force on the boom.

I discuss it that way because the other way is simpler. If you understand this, then you’ll understand that.

The downhaul exerts a point-force on the boom.

Whether we call a force an effort or a load, or the fulcrum’s point-force, depends on the particular manner that we’re speaking of, in which the boom acts as a lever.

...and that depends on what force(s) we want to look at or discuss.

As Cracked-Pot said, a static system gives us some freedom in that matter.

In my reply that Cracked-Pot quoted, I was speaking of how the boom could be regarded as a lever with the downhaul as its fulcrum, and with the sail-foot as its distributed effort and load, on opposite sides of the fulcrum.

…due to the sail on one side and a concentrated load due to the downhaul on the other side.

With the Balanced-Lug, which is what we were talking about, the downhaul isn’t to one side of the sail-foot. It’s some distance aft of the tack. Take another look at your boat, Cracked-Pot.

This is Part I of this reply.

Part II follows in a few minutes.

Michael Ossipoff

[Novice091015]

Part II of reply to Crackpot:

If these loads are not balanced the boom will move up or down. If their moments do not cancel the boom will rotate

In Explanations, I told why it’s a static system…why the spars don’t rotate after the downhaul has been tightened and the system is set. …in particular, why there can be luff-tension, with the downward pull on the tack resisted by an upward pull at the throat—even if we disregard gravitational and sheeting forces.

(Hint: It has to do with levers.)

Cracked-Pot, I recommend that you re-read Explanations.

Continuing Cracked-Pot’s sentence:

… ABOUT THE CENTER OF MASS OF THE BOOM, NOT THE DOWNHAUL ATTACHMENT POINT, OR THE LUFF, OR THE LEECH.

Incorrect. When the downhaul has been tightened, and if the moments of the effort and the load (the pulls of the sail-foot forward and aft of the downhaul, in the system I speak of) weren’t balanced, then the boom would rotate about its point of attachment to the downhaul.

You need a lot of teaching, before you're qualified to discuss these subjects. Sorry, but I don't have the time to continue teaching you.

Cracked-Pot continues:

…and before you spout off about how once the downhaul has been fully tensioned and the rig is static that the downhaul then becomes the fulcrum you should understand that for a static beam, both forces and moments are balanced.

No one said or implied otherwise.

Cracked-Pot continues:

It is neither rotating nor translating, and thus any point in space …

Well, any point on the lever…

…can be considered to be the fulcrum

Yes, and so one can speak of the yard’s halyard-attachment, or the boom’s downhaul attachment, as the fulcrum.
…contrary to what you tried to say in another part of your self-contradictory post.

, so to speak of a single point, such as the downhaul attachment point as being The Fulcrum, is absurd

Nonsense. The fact that, in a static system, we have some freedom regarding what point on the lever we speak of as the fulcrum, doesn’t mean that we can’t speak of some particular point, such as the downhaul-attachment, as the fulcrum (without the capitalizing “The Fulcrrum”).

Maybe Cracked-Pot wants to pretend that I said that there was only one point that could be spoken of as the fulcrum, or that we could rightly only speak of one manner in which a spar can act as a lever. Pretending may be fun, but I didn’t say that.

, as it has no greater claim than Alpha Centauri to being the fulcrum.

The fulcrum is a point on the lever.

Alpha Centuri isn’t a point on your boat’s spars, unless your boat is different from the way it’s portrayed in your photo.

(…aside from the fact that Alpha Centuri isn’t a point)

Cracked-Pot quoted me:

For example, the sail's downward pull on the yard-heel is resisted by the upward leverage from the sail's downward pull on the yard-tail.

(To that sentence, I should have added “in addition to the other contributions to downward moment on the yard-tail—such as the weight of yard-tail, sail, and boom-tail, and the downward component of the sheeting-force”.)

Cracked-Pot answers:

This explanation fails to explain, as does Explanations, why there is a crease running from throat to clew.

I’ve, many time, clarified what Explanations sets out to explain. I’m not going to keep repeating it for you.

Your funny crease is the result of your mis-adjustment. That’s its explanation.

Don’t expect Explanations to explain how or why you mis-adjust your sail.

That crease is there because the center of mass of the yard is aft of the halyard. Gravity thus causes the forward end of the yard to rotate upward.

Normally that’s only one of several contributions to the downward moment exerted on the yard-tail.

There’s also the weight of the sail and boom-tail pulling down on the sail, which pulls down on the yard-tail.

There’s also the downhaul-induced downward pull of the boom on the sail (and the sail’s resulting downward pull on the yard-tail).

There’s also the downward component of the sheeting-force (…which admittedly diminishes greatly when the boom is swung out far, as when sailing off the wind).

Does the sail likewise pull down on the yard-heel?

Of course. That creates a moment that opposes the downward moment on the yard-tail. With the yard acting as a lever, with fulcrum at its halyard-attachment, those pulls on both sides of the halyard attachment prevent further rotation of the yard, and make it a static system.

…tensioning the luff in the process.

Neither end of the yard can descend because it’s held up by the leverage of the downward pull on the yard’s opposite end.

Cracked-Pot continues:

However, the luff tension isn't the major force resisting this [the upward pull at the throat]. It is resisted by tension that runs across the sail from throat to clew, causing the crease.

Cracked-Pot, Explanations didn’t claim to explain the forces on your mis-adjusted sail.

Your above-quoted two sentences (which I’ll refer to as Cracked-Pot’s throat-pull-resistance theory) claims that all of the force resisting the throat’s upward pull comes from the clew :^)

Well, the clew gets some downward pull from the boom’s weight and moment, and also from the downward component of the sheeting-force (depending on how far the boom is swung out).

Cracked-Pot thinks that’s the only force resisting the throat’s upward pull.

The downhaul is pulling down hard on the boom, and therefore on the sail-foot, forward and aft of the downhaul. Of course the sail-foot forward of the downhaul is pulled on harder by the nearby downhaul—compared to most of the sail-foot aft of the downhaul (especially at the clew).

It couldn’t be, could it, that that might contribute to some opposition to the throat’s upward pull? :^)

Cracked-Pot, you need to study the matter more before you tell us how it is. I recommend that you re-read Explanations.

At no point have you ever touched on this as a possibility, and it's a fundamental reason why your string and stick model is a poor model of a balanced lug.

Well, I wasn’t trying to model your mis-adjustment.

But I admit that my explanation isn’t consistent with “Crackpot’s throat-pull resistance theory” :^)

Statements such as
sail's downward pull on the yard-tail
, while not technically incorrect, also say nothing meaningful.

Except for a major contribution to the downward moment on the yard-tail, resulting in an upward moment on the yard-heel, and a resulting upward pull on the sail-head section attached to it. :^)

…and thereby a significant contribution to luff-tautness.

…and to the balance of forces that steadies the yard.

What matters isn't that the sail is pulling down on the peak of the yard, but how that force is distributed across the area of the sail.

…if you want Explanations to explain how best to achieve an optimum 3D sail-shape :^)

Explanations is about the principle and means by which it’s possible for a Lug-Rig to tension the luff and leech.

Anything that contributes to the downward moment on the yard-tail matters.

Anything that significantly contributes to it matters very much.

If the distribution isn't correct the sail doesn't work.

Then adjust your sail-adjustment lines right.

But that isn’t a topic of Explanations.

So, as I said, if you read Explanations, and then mis-adjust your sail, don’t come crying to me.

Michael Ossipoff

[Yeadon]

The topic at hand is "How to rid your space of mcmullets." Please avoid thread drift.

[Novice091015]

Now I've completed this round of replies.

People had said that I should leave this thread open. I listened to them, and left it open.

Problem: Many of you-lot have been complaining and complaining about how long the thread continues. Complaining, while evidently unable to stop reading it and posting to it.

James said that it's my fault. Well, maybe it is my fault, when I don't close the thread.

Yes, I know that some have said that it would be good to leave the thread open so that people can continue their discussions of boating topics, photos, etc. Problem: That isn't what they're doing.

Because I've been leaving this thread open, you-lot have been unable to stay away from it, and from the raging controversy that you insist on having, regarding Explanations. You'd rather discuss me than discuss boats, or sail your boats.

You can't stop. You can't help it. And it's my fault, if I don't close the thread--for your own good.

"Help me, I can't stop writing about you and your article!"

Alright, I will help you by closing this thread.

I apologize to those who suggested leaving the thread open for discussion of other topics. That mostly is not what's happening in this thread, for one thing. For another thing, someone pointed out that it would be better for those topics to be discussed in one or more other threads.

I'm not closing the thread out of defiance to those who want it open for discussion of boating topics appropriate for this forum. I do it with regretful apologies, that it's necessary. But surely you understand:

Don't you want me to let your friends post about boats again? Don't you want me to let your friends have some time to do some sailing?

So, with regret for the necessity, I'm closing this thread for their own good (referring to those who can't stop posting to and with regard to me and Explanations.

Let it go! Some of you can't. So I have to help them, by closing the thread.
-----------------------------------------------------------------------------------------------------------------

One more thing on the "cult" subject:

But the most obvious cultish attribute of this community is their "Us vs the Outsider" attitude. That's found in every cult. And, when it's present in the dramatically pronounced form found here, then your "community" has the word "Cult" written all over it.

Sure, there are distinct inbred Wrong Turn attributes. But the resemblance to Children of the Corn is much more impressive and obvious.

"Already the Outlanders have come!"

You see, it's that "Boaters vs an Outsider" thing.

Ok, now I'm closing this thread so that the wretched of you (you know who you are) can finally get back to discussing boats and sailing, and finally get back to doing some sailing (Remember what that is?)

Some of you, including some of the veteran sailors, riggers and boat-builders, have always been civil to me. I emphasize that I'm not referring to you by my criticisms above, and I thank you for your civility and hospitality.
You've made this a not-entirely negative experience.

Michael Ossipoff

[Novice091015]

Thread closed.