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!!
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.