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PostPosted: Wed Nov 06, 2013 1:27 pm 
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OMG. World Peace in the Hobie 16 World. The guns have stopped firing, the war is over...............

Now, about the 6:1 downhaul and I saw mention of a 3:1 outhaul. What is that?


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PostPosted: Wed Nov 06, 2013 1:34 pm 
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I'm glad I switched from mechanical to electrical engineering :D

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PostPosted: Wed Nov 06, 2013 1:57 pm 
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sxrracer wrote:
OMG. World Peace in the Hobie 16 World. The guns have stopped firing, the war is over...............

Now, about the 6:1 downhaul and I saw mention of a 3:1 outhaul. What is that?


6:1 down haul is stacking boats on a trailer to sail in Mexico

3:1 out haul is only bringing 2 cat tracks so you have to pull boats on the beach 3 at a time

sheesh, I thought everyone knew that ...

:mrgreen:

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PostPosted: Wed Nov 06, 2013 4:12 pm 
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RHoughVYC wrote:
sxrracer wrote:
OMG. World Peace in the Hobie 16 World. The guns have stopped firing, the war is over...............

Now, about the 6:1 downhaul and I saw mention of a 3:1 outhaul. What is that?


6:1 down haul is stacking boats on a trailer to sail in Mexico

3:1 out haul is only bringing 2 cat tracks so you have to pull boats on the beach 3 at a time

sheesh, I thought everyone knew that ...

:mrgreen:

ok, so you only have to make 3 trips with 2 pair of trax.......... so, that means you only leave 2 pair of trax in the sand............ Never would have figured that out..........


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PostPosted: Wed Nov 06, 2013 6:33 pm 
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rattle 'n hum wrote:
If the sum of all the forces is zero, and the force in that section of the Aussie halyard is 1/3 of the older system in that section, then there has to be more force in the other components attached to the mast (pigtail and shrouds).


That by itself is not valid logic. Less force somewhere doesn't have to mean more force somewhere else. It can mean less force somewhere else.

Quote:
And I submit to RH's point that it's not compression that causes the bending. Since the halyard is located outside the mast column, it's actually a moment with a very short arm, no?


I agree, too. The moment is a small component of the overall force (the rest is compression) but the bending is all we care about. 1/3 the halyard tension acting on the mast between the tang and the cleat, 1/3 the compression, 1/3 the bending moment. That's really the whole thing in a nutshell.

If anyone wants to start this over with a clean mind, think about it like this: Use the Aussie halyard. Then tie two lines to the tang, install two more cleats on the side of the mast, and then tension and cleat the two lines the way you did the Aussie halyard. Now you have three tight lines trying to bend the mast instead of one, no extra loads anywhere else. That is exactly the difference.

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PostPosted: Thu Jan 24, 2019 8:43 am 
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So, I too, an engineer, read through this years after it was posted. I had just started sailing in 2013, and it was an Ericson 32.

What if you made the jib halyard a 2:1 system, by having it permanently attached close to the base of the mast, up to the tang through a block, then through a block connected to the jib, then back through a block at the tang and down the other side of the mast to a cleat. this gives you opposing forces on both sides of the mast, creating the least amount of mast bend, 2:1 control and a reduction in extra halyard length.

I might give this a shot, and as I am from Dallas, TX, if it works it should be the Big D Halyard :p . Also because without dyneema would introduce a lot of stretch :D


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PostPosted: Thu Jan 24, 2019 10:52 am 
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mrarmyant wrote:
So, I too, an engineer, read through this years after it was posted. I had just started sailing in 2013, and it was an Ericson 32.

What if you made the jib halyard a 2:1 system, by having it permanently attached close to the base of the mast, up to the tang through a block, then through a block connected to the jib, then back through a block at the tang and down the other side of the mast to a cleat. this gives you opposing forces on both sides of the mast, creating the least amount of mast bend, 2:1 control and a reduction in extra halyard length.

I might give this a shot, and as I am from Dallas, TX, if it works it should be the Big D Halyard :p . Also because without dyneema would introduce a lot of stretch :D


Wow, someone is bored- resurrecting this ancient thread! It doesn't matter whether you have a 1:1 6:1 or 10:1 jib halyard arrangement or the lines cleated to the mast two places, etc., etc. the tension at the mast tang and on the bridle will always be equal and opposite! Regardless how you rig it, the jib halyard applies a vector load which has two components, a vertical component that pulls down along the axis of the mast (mast compression) which is (and must be) opposed by an equal and opposite upward force applied to the mast by the foot/frame of the boat. It also has a horizontal component, applied at the point of attachment, which is balanced by the horizontal component of the shrouds (which also have vertical components) and, to some degree also the weight of the sail and boom and main sheet tension. When sailing, these loads can change depending on the wind action on the sail. But, back to the original issue, regardless of how you rig the jib halyard, the ONLY force that changes is the amount of force you need to manually apply to tension it- 1:1 = harder, 6:1 = easier. It is called "mechanical advantage" which is the whole reason for block and tackle anywhere. Of course, the more sheaves the more halyard you need and the more you need to stow! :o Also, with more mechanical advantage it is much easier to over-tension the halyard.

p.s. I hadn't read this thread in quite a few years and was surprised when I went back through some of the pages at the number of "opinions" not based in fact. Some also accused me of not having an Aussie rig. I do have one and that is what originally caused me, after examining it, to challenge the wild claims. Yes, I am an engineer, though most of my (retired) work has been woodworking tool design. I designed two specialty woodworking accessories that have been successfully marketed for several years and even have a patent. If you are interested you can Google INCRA I-BOX and Infinity Lock Miter Master.

As to bending- until the metal starts failing (or the fibers on one side of a wooden a dowel compress more than the others), a pure axial load will not cause bending. You need to apply some sort of unbalanced non-axial (side) load- pushing or pulling to the side, by hand, by the sail, etc. somewhere between the points where the axial load is applied, to get it started. Once bending starts, the compression forces at one end (tang) and the opposite force at the other end (mast foot) are no longer axial with the mast, so bending becomes easier and will increase with greater (formerly) axial loads- like a long bow.

My final point- Other than making it easier to tension the jib, there may be some benefit to the Aussie rig. Anecdotally, it may allow the mast to rotate easier, etc. I didn't do much sailing with the old rig to compare and haven't done that analysis, so I can't say, but it isn't because it reduces mast compression by 60%, because it doesn't do that!

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Last edited by aschaffter on Thu Jan 24, 2019 11:02 am, edited 1 time in total.

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PostPosted: Thu Jan 24, 2019 11:01 am 
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You might have missed what I was saying. In this instance it would be 2:1 and apply equal tension loads to each side (port and starboard) of the mast rather than just reducing it like the aussie halyard.

I am aware of mechanical advantage, again, I'm an engineer.

I'm talking about a new design that helps to remove or at least equate the mast bend port/starboard. It is 2:1, meaning less line than 3:1, and a lower mechanical advantage :p

The 66% claim is clearly nuts and only applies to the reduction in tension between two fixed points on the mast, not the mast step. That number being derived also isn't exactly right but its all irrelevant to what I'm talking about - a new way to hoist a jib :D


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PostPosted: Thu Jan 24, 2019 1:15 pm 
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mrarmyant wrote:
You might have missed what I was saying. In this instance it would be 2:1 and apply equal tension loads to each side (port and starboard) of the mast rather than just reducing it like the aussie halyard.

To what end??? And the Aussied doesn't reduce anything!
mrarmyant wrote:
I'm talking about a new design that helps to remove or at least equate the mast bend port/starboard. It is 2:1, meaning less line than 3:1, and a lower mechanical advantage :p

??? How would that help to remove or do anything to the bend? Seriously???
mrarmyant wrote:
The 66% claim is clearly nuts and only applies to the reduction in tension between two fixed points on the mast, not the mast step. That number being derived also isn't exactly right but its all irrelevant to what I'm talking about - a new way to hoist a jib :D

You are correct, the 66% is clearly nuts, but it does not apply tension between "two fixed points on the mast"!!! It applies force between a fixed point on the mast (cleat near the bottom) through one or more pulley sheaves, to the halyard, to the bridle and finally to the bows. The section of halyard from the cleat to the top Aussie sheave has no effect- it is just part of the combined vector- the same downward force is applied to the mast at the tang and is opposed by an upward force applied by the foot/frame to the bottom of the mast! All that stuff in between does not change the axial compressive force applied to the mast. There is no part of the mast that is not under compression, even the comp tip- the main halyard applies compression to the mast from the masthead sheaves. It is equal and opposite to the sum of the forces applied by the mast cleat at one end and the weight of the sail, boom, downhaul, etc. and some of this compressive force (all those caused by gravity) is also applied to the mast foot/frame.

You are still missing the big picture- regardless of how you attach lines to the mast, between cleats, etc. etc., the (downward) vertical vector applied by the halyard (and shrouds, and sail (weight, etc.), boom, main sheet, MUST be equal and opposite to the (upward) force applied by the frame/mast foot. Unless sailing, where forces change to some degree, the rigging is a balanced system, if it were not the halyard would be pulling the bows up towards the tang or the mast would be forced down into the frame, and this motion would continue until all forces are balanced and in equilibrium- which they are.

Take a step back, draw it if you must, add the vector directions. Remember every vector can be broken down into its orthogonal, X, Y, Z components. Start by adding one vector at a time, but remember each vector must have one or more vectors that when summed are equal and opposite. It is a "closed and balanced system," not just one line pulling on the mast. It is time to dig out your Statics and Dynamics textbook and do some reading.

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PostPosted: Fri Jan 25, 2019 7:29 am 
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How does it help? How do two opposing lines cancel out the net force of the bend? If you can't see this then there is probably no point in a further discussion with you. Again, you are talking to an m-effing engineer, not a child. I am very aware of breaking down vectors. If you had a bow with a bow string, and applied a string with equal tension to the opposite side of the bow, their forces would counteract each other, but increasing the internal compressive load on the bow. Nothing I am talking about is doing anything to the mast step or foot. I am trying to equalize the forces on the mast port to starboard instead of the jib halyard pulling it to one side.

Current system the mast itself is providing the opposite force moments to the bow string effect. It needs help to reduce the bend from port to starboard. Using the same line from one side up to the top then back down the other helps to equalize the forces.

It is time for you to bow out, you clearly can't picture what I am saying, or know what you are talking about. I have lost any interest or respect for your opinions.

I was hoping to heat from Anton, he and I are more on the same page in thinking about reducing the mast bend.

aschaffter wrote:
mrarmyant wrote:
You might have missed what I was saying. In this instance it would be 2:1 and apply equal tension loads to each side (port and starboard) of the mast rather than just reducing it like the aussie halyard.

To what end??? And the Aussied doesn't reduce anything!
mrarmyant wrote:
I'm talking about a new design that helps to remove or at least equate the mast bend port/starboard. It is 2:1, meaning less line than 3:1, and a lower mechanical advantage :p

??? How would that help to remove or do anything to the bend? Seriously???
mrarmyant wrote:
The 66% claim is clearly nuts and only applies to the reduction in tension between two fixed points on the mast, not the mast step. That number being derived also isn't exactly right but its all irrelevant to what I'm talking about - a new way to hoist a jib :D

You are correct, the 66% is clearly nuts, but it does not apply tension between "two fixed points on the mast"!!! It applies force between a fixed point on the mast (cleat near the bottom) through one or more pulley sheaves, to the halyard, to the bridle and finally to the bows. The section of halyard from the cleat to the top Aussie sheave has no effect- it is just part of the combined vector- the same downward force is applied to the mast at the tang and is opposed by an upward force applied by the foot/frame to the bottom of the mast! All that stuff in between does not change the axial compressive force applied to the mast. There is no part of the mast that is not under compression, even the comp tip- the main halyard applies compression to the mast from the masthead sheaves. It is equal and opposite to the sum of the forces applied by the mast cleat at one end and the weight of the sail, boom, downhaul, etc. and some of this compressive force (all those caused by gravity) is also applied to the mast foot/frame.

You are still missing the big picture- regardless of how you attach lines to the mast, between cleats, etc. etc., the (downward) vertical vector applied by the halyard (and shrouds, and sail (weight, etc.), boom, main sheet, MUST be equal and opposite to the (upward) force applied by the frame/mast foot. Unless sailing, where forces change to some degree, the rigging is a balanced system, if it were not the halyard would be pulling the bows up towards the tang or the mast would be forced down into the frame, and this motion would continue until all forces are balanced and in equilibrium- which they are.

Take a step back, draw it if you must, add the vector directions. Remember every vector can be broken down into its orthogonal, X, Y, Z components. Start by adding one vector at a time, but remember each vector must have one or more vectors that when summed are equal and opposite. It is a "closed and balanced system," not just one line pulling on the mast. It is time to dig out your Statics and Dynamics textbook and do some reading.


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PostPosted: Fri Jan 25, 2019 2:04 pm 
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mrarmyant wrote:
How does it help? How do two opposing lines cancel out the net force of the bend?


They will not cancel out the bending forces, they are axial and too close to the geographic center of the mast- why do you think most sailboats with taller masts have spreaders and Z rigging? The mast provides more rigidity than your ropes ever will! With your rig, the mast will just bend in a direction at some off angle or perpendicular to an imaginary line running horizontally between your "axial" shrouds! Depending on how much you tension them, your lines could, in fact, actually be a self-contained reason for mast compression and bend, just like a bow!!

Image

mrarmyant wrote:
If you can't see this then there is probably no point in a further discussion with you. Again, you are talking to an m-effing engineer, not a child. I am very aware of breaking down vectors.


Maybe instead of snark, you will learn something. You have certainly made a poor case for your claims!

mrarmyant wrote:
If you had a bow with a bow string, and applied a string with equal tension to the opposite side of the bow, their forces would counteract each other, but increasing the internal compressive load on the bow. Nothing I am talking about is doing anything to the mast step or foot. I am trying to equalize the forces on the mast port to starboard instead of the jib halyard pulling it to one side.


No, no, no! You are obviously talking about a slack/straight bow at the start since you can't run a line on the opposite side as the bow string on a tensioned bow. There are two ways you can easily demonstrate for yourself the fallacy of your concept- take a 4' long X 3/4" diam. dowel. Run a strong string or wire down each side (you can use a continuous string/wire) if you want. Anchor the end(s) to the end(s) of the dowel. Then apply axial compressive force with your hands. Guess what? The dowel will bend just as easily as if you didn't have the wires! It will seek the path of least resistance. The bend may initially be toward a spot 90° around the dowel from the location of the wires or some other direction, but that will only last until they go slack, which they will do quickly then who knows how and in which direction it will continue to bend. As you add compressive force, the dowel will continue to bend as one wire slips around the dowell and both wires quickly go slack and hang next to each other. And, if you pre-tension the wires up to the point just before the dowel starts to bend, it will bend even easier when you push on the ends. For the second demonstration place the dowel horizontally on supports at each end above the floor, table, etc. Rotate the dowel in a direction of your choice. Now push down on the side of the dowel at the mid point. The dowel will easily bend, and the wires will quickly go slack and have no impact on the ease of bending.

To equalize the bending forces side to side, ideally you would need a line attached to each side of the mast, somewhere near the midpoint, and running horizontally to imaginary self-adjusting "skyhooks" to port and starboard, angled stays running from the same place on the mast to chain plates, or like many boats, a system of spreaders and angled stays. However, that would eliminate important mast rotation and possibly impact jib handling.

mrarmyant wrote:
Current system the mast itself is providing the opposite force moments to the bow string effect. It needs help to reduce the bend from port to starboard. Using the same line from one side up to the top then back down the other helps to equalize the forces.


The mast structure does in fact provide some resistance to bending, but since the mast is always under compression, it doesn't take much sideways force (like wind forces on the sail along the luff) between the foot and the jib tang, to cause bending. Depending on how much the jib halyard is tensioned and the amount of flex in line (and the hulls!), the amount of bend will vary, but a certain amount may be present from the beginning and throughout the current sailing session. The amount of bend could also actually increase. Once a bow starts to bend, it requires less and less string force to achieve more bend, despite materials and design work to lessen the effect, until the bow snaps (one reason compound bows are popular- the tension on the string is more uniform throughout the pull and release). The same will be true of the mast. Again, your lines will do nothing to equalize the forces, because they are too axial and too close to the geometric center of the mast. A similar but not exactly the same condition occurs with an I-Beam or torsion box- both are more rigid/resist bending if the shear web is larger (taller, not thicker) because the flanges (or skins), which are in tension (bottom) and compression (top) are farther from the neutral point! An I-Beam with a short shear web has poor resistance to bending.

mrarmyant wrote:
It is time for you to bow out, you clearly can't picture what I am saying, or know what you are talking about. I have lost any interest or respect for your opinions.
I understand your flawed analysis perfectly, but, unfortunately, the same can't be said for you.

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PostPosted: Sat Jan 26, 2019 8:05 am 
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Once again, not interested in your opinion. Spreaders are used because stays hold the mast up right. The jib halyard doesnt, you want it to have as little effect on the mast as possible...

After reading pages of your dribble your overall comments lead to the aussie doing nothing when many reported improved tacking and mast rotation. Even if it's cowboy engineering, you (censored) on it, or me seeing a trend in then equalizing of port/starboard forces, and you (censored) on that, does literally nothing. Your thinking seems so old and uninspiring you sound like a very old man from an era that didn't want certain groups of people drinking at water fountains.

Go away.

aschaffter wrote:
mrarmyant wrote:
How does it help? How do two opposing lines cancel out the net force of the bend?


They will not cancel out the bending forces, they are axial and too close to the geographic center of the mast- why do you think most sailboats with taller masts have spreaders and Z rigging? The mast provides more rigidity than your ropes ever will! With your rig, the mast will just bend in a direction at some off angle or perpendicular to an imaginary line running horizontally between your "axial" shrouds! Depending on how much you tension them, your lines could, in fact, actually be a self-contained reason for mast compression and bend, just like a bow!!

Image

mrarmyant wrote:
If you can't see this then there is probably no point in a further discussion with you. Again, you are talking to an m-effing engineer, not a child. I am very aware of breaking down vectors.


Maybe instead of snark, you will learn something. You have certainly made a poor case for your claims!

mrarmyant wrote:
If you had a bow with a bow string, and applied a string with equal tension to the opposite side of the bow, their forces would counteract each other, but increasing the internal compressive load on the bow. Nothing I am talking about is doing anything to the mast step or foot. I am trying to equalize the forces on the mast port to starboard instead of the jib halyard pulling it to one side.


No, no, no! You are obviously talking about a slack/straight bow at the start since you can't run a line on the opposite side as the bow string on a tensioned bow. There are two ways you can easily demonstrate for yourself the fallacy of your concept- take a 4' long X 3/4" diam. dowel. Run a strong string or wire down each side (you can use a continuous string/wire) if you want. Anchor the end(s) to the end(s) of the dowel. Then apply axial compressive force with your hands. Guess what? The dowel will bend just as easily as if you didn't have the wires! It will seek the path of least resistance. The bend may initially be toward a spot 90° around the dowel from the location of the wires or some other direction, but that will only last until they go slack, which they will do quickly then who knows how and in which direction it will continue to bend. As you add compressive force, the dowel will continue to bend as one wire slips around the dowell and both wires quickly go slack and hang next to each other. And, if you pre-tension the wires up to the point just before the dowel starts to bend, it will bend even easier when you push on the ends. For the second demonstration place the dowel horizontally on supports at each end above the floor, table, etc. Rotate the dowel in a direction of your choice. Now push down on the side of the dowel at the mid point. The dowel will easily bend, and the wires will quickly go slack and have no impact on the ease of bending.

To equalize the bending forces side to side, ideally you would need a line attached to each side of the mast, somewhere near the midpoint, and running horizontally to imaginary self-adjusting "skyhooks" to port and starboard, angled stays running from the same place on the mast to chain plates, or like many boats, a system of spreaders and angled stays. However, that would eliminate important mast rotation and possibly impact jib handling.

mrarmyant wrote:
Current system the mast itself is providing the opposite force moments to the bow string effect. It needs help to reduce the bend from port to starboard. Using the same line from one side up to the top then back down the other helps to equalize the forces.


The mast structure does in fact provide some resistance to bending, but since the mast is always under compression, it doesn't take much sideways force (like wind forces on the sail along the luff) between the foot and the jib tang, to cause bending. Depending on how much the jib halyard is tensioned and the amount of flex in line (and the hulls!), the amount of bend will vary, but a certain amount may be present from the beginning and throughout the current sailing session. The amount of bend could also actually increase. Once a bow starts to bend, it requires less and less string force to achieve more bend, despite materials and design work to lessen the effect, until the bow snaps (one reason compound bows are popular- the tension on the string is more uniform throughout the pull and release). The same will be true of the mast. Again, your lines will do nothing to equalize the forces, because they are too axial and too close to the geometric center of the mast. A similar but not exactly the same condition occurs with an I-Beam or torsion box- both are more rigid/resist bending if the shear web is larger (taller, not thicker) because the flanges (or skins), which are in tension (bottom) and compression (top) are farther from the neutral point! An I-Beam with a short shear web has poor resistance to bending.

mrarmyant wrote:
It is time for you to bow out, you clearly can't picture what I am saying, or know what you are talking about. I have lost any interest or respect for your opinions.
I understand your flawed analysis perfectly, but, unfortunately, the same can't be said for you.


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PostPosted: Sat Jan 26, 2019 9:43 am 
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mrarmyant wrote:
Once again, not interested in your opinion. Spreaders are used because stays hold the mast up right. The jib halyard doesnt, you want it to have as little effect on the mast as possible...

After reading pages of your dribble your overall comments lead to the aussie doing nothing when many reported improved tacking and mast rotation. Even if it's cowboy engineering, you (censored) on it, or me seeing a trend in then equalizing of port/starboard forces, and you (censored) on that, does literally nothing. Your thinking seems so old and uninspiring you sound like a very old man from an era that didn't want certain groups of people drinking at water fountains.

Go away.


:lol: :lol: :lol: "The jib halyard doesnt" (hold the mast upright) :lol: :lol: :lol: Say what?!?!?

Sorry to burst your bubble but I am talking fact, not opinion. From the get-go, it appears you have no clue! Spreaders and shrouds have two purposes- to provide left/right support to the mast AND, in the case of angled shrouds, provide L/R rigidity to prevent bending along the length of the mast. If you remove the spreaders and angled shrouds and rig just one set of shrouds between the masthead to the chain plates on each side, the mast will still stay upright (L/R), but sure will be extremely flexible and could even buckle fairly easily under sailing side loads. Remove the jib halyard (and the "temporary" forestay, which is only used to hold the mast up when the jib is down and is slack when the jib is rigged), from your Hobie and see what happens to the mast!!!!! It will come crashing down on the rear crossbar or your head!! Come on, if you own and sail a Hobie you should know this. Or, are you one of those people that never learned how to rig your boat properly and use the "temporary" forestay to hold your mast upright when rigged for sailing????

If you don't believe me, how about Matt Miller. See his response https://www.hobie.com/forums/viewtopic.php?f=14&t=1943 to a typical rookie rigging question (I added emphasis): "Forestay length is very long to allow for maximum mast rake, but the stay itself is not a structural part of the sailing rig. It is just used for rigging when the jib is not up. Once you raise the jib and tension it's halyard, the "forestay" wire goes slack and the rig is loaded onto the jib's internal luff wire... it becomes the actual forestay. The slack "forestay" should never take any sailing loads away from the jib luff wire. This insures that the jib wire can stay taut and as straight as possible."

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PostPosted: Sat Jan 26, 2019 6:49 pm 
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First, The jib halyard is not meant to hold a mast up like a stay is on most sailboats, which I assumed was what we were talking about since your dumb ass brought up spreaders, which a hobie doesn't have (or do you never actually sail but just look at photos? see I can be a dumb prick too).

Admin: <<SNIP>>

I want to hear from anyone else.

aschaffter wrote:
mrarmyant wrote:
Once again, not interested in your opinion. Spreaders are used because stays hold the mast up right. The jib halyard doesnt, you want it to have as little effect on the mast as possible...

After reading pages of your dribble your overall comments lead to the aussie doing nothing when many reported improved tacking and mast rotation. Even if it's cowboy engineering, you (censored) on it, or me seeing a trend in then equalizing of port/starboard forces, and you (censored) on that, does literally nothing. Your thinking seems so old and uninspiring you sound like a very old man from an era that didn't want certain groups of people drinking at water fountains.

Go away.


:lol: :lol: :lol: "The jib halyard doesnt" (hold the mast upright) :lol: :lol: :lol: Say what?!?!?

Sorry to burst your bubble but I am talking fact, not opinion. From the get-go, it appears you have no clue! Spreaders and shrouds have two purposes- to provide left/right support to the mast AND, in the case of angled shrouds, provide L/R rigidity to prevent bending along the length of the mast. If you remove the spreaders and angled shrouds and rig just one set of shrouds between the masthead to the chain plates on each side, the mast will still stay upright (L/R), but sure will be extremely flexible and could even buckle fairly easily under sailing side loads. Remove the jib halyard (and the "temporary" forestay, which is only used to hold the mast up when the jib is down and is slack when the jib is rigged), from your Hobie and see what happens to the mast!!!!! It will come crashing down on the rear crossbar or your head!! Come on, if you own and sail a Hobie you should know this. Or, are you one of those people that never learned how to rig your boat properly and use the "temporary" forestay to hold your mast upright when rigged for sailing????

If you don't believe me, how about Matt Miller. See his response https://www.hobie.com/forums/viewtopic.php?f=14&t=1943 to a typical rookie rigging question (I added emphasis): "Forestay length is very long to allow for maximum mast rake, but the stay itself is not a structural part of the sailing rig. It is just used for rigging when the jib is not up. Once you raise the jib and tension it's halyard, the "forestay" wire goes slack and the rig is loaded onto the jib's internal luff wire... it becomes the actual forestay. The slack "forestay" should never take any sailing loads away from the jib luff wire. This insures that the jib wire can stay taut and as straight as possible."


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PostPosted: Sun Jan 27, 2019 2:55 pm 
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mrarmyant wrote:
First, The jib halyard is not meant to hold a mast up like a stay is on most sailboats


Let's try to keep it civil here. mrarmyant, what Hobie model do you sail?

On the Hobie 16 the jib has a luff wire. As noted, the "forestay" on this boat is only loaded when the jib is not hoisted. The jib halyard is used to load the jib luff wire and overcome the load on the "forestay". The jib luff wire assumes the job of the forestay and holds the mast forward while the shoruds hold the mast aft and in port starboard column. These three wire are the mast stays.

This is where the discussion about the Aussie (been standard on the Hobie 16 for many years now) halyard and the effect on mast compression and bend.

The original jib halyard system is more like what you have been writing about. The halyard passed through a block at the mast tang (hounds). Then down the side of the mast to a point where there was a 3:1 purchase to gain tension on the halyard. You have to tension the halyard to pull the mast forward and tension against the shrouds. Proper rig tension on the 16 requires the shrouds to be taut and not allow the jib luff to bend to leeward while under sail. This tension placed a considerable 1:1 load on the halyard wire up the side of the mast which acted like a bow string and caused the mast to bend. This bend would have to be overcome during each tack and would sometimes cause the mast to counter rotate.

In comes the Aussie system.

Image

This placed the purchase between the jib head and tang. The load on the halyard line running down the side of the mast is greatly reduced. This load is not enough to cause the type of mast bend (bow) as seen in the original system. The mast now stands straight under significant rig tension. Tacks are far easier and counter rotation is less of an issue.

Also... there are many models of Hobie Cats that do have spreaders and diamond wires. Hobie 18, 20, 21SE 18SX ... all have spreaders. These are used on larger rigs or rigs with less than sufficient mast extrusions to support the sail loads without excessive mast bend. These spreaders can be adjusted fore and aft and diamond wires can be adjusted tight to loose to allow the mast to bend to a point. The Aussies liked to sweep the H18 spreaders aft and tighten the diamonds to induce mast bend directly aft to help flatten the main in high winds.

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Warranty and Technical Support
Hobie Cat USA
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