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On my 96X, I removed the stock dog-leg crutch and had a welder make a bracket (SS) in front of Pedestal and use a straight SS pole with original roller assembly. Shortened the spreaders, no Mac Dance and sails better. Removed CDI furling, went to hanked on jibs. Don't use lifting system, since mast is light (I am 69). In the water in 20 minutes and can beat most X boats probably due to weight shift improvements and spending more time on the water learning sailing skills. Go on the VYC page and see Murv's ideas for stream lining the set-up and take down process.

Newell wrote: Go on the VYC page and see Murv's ideas for stream lining the set-up and take down process.

Can you post a link? Some of us just can't remember where to find things with out a "GOTO" button.

Newell wrote:Don't use lifting system, since mast is light (I am 69).

I envy you. I've got no shoulders left, and sometimes have a hard time just raising my arms. I can pull as hard as I want (like sheets), since it pulls the shoulders apart rather than mushing the ball into the socket where there's no cartilage left, but pushing is a problem.

Found this but not totally related to this discussion:

http://www.youtube.com/watch?v=esgfY209hGs

Murv copied my shortened spreader setup.

See this for take down for trailering.

http://www.youtube.com/watch?v=ekwKSnCAX-A

I have been a out-of-state member of the VYC since 98 and it is a great club for trailor sailors.

http://www.vycsd.com/

Murv is not only greatly admired in the club but he has always been willing to teach others and share his great ideas. You may want to talk to him and if so pm me for a #.

Godamn just lost my post now but if this works should show view of mast support and pvc /alum piece to support furler and how spreaders are above lifelines.

Well it worked that time photobucket have changed their format and it doesn't take much to confuse me.
The mast support is a piece of 4" stormwater pipe with a tee on one end and the top sliced out of the tee which is spread using heat and a bit of carpet added to stop rubbing, the bottom is heated to make it fit into the mast bracket and the use a 1' piece of 4" sewer pipe with slots cut to fit over the mast bracket and slide over the stormwater.
The tee is lashed to the mast with an ocky strap and the bit of sewer is lashed to the mast bracket with another ocky strap.
This allows the stormwater on the mast to be raised without coming adrift.

Hi Newell,

I very much enjoyed watching the videos; Murv is as you describe him.
Picked up one or two ideas; thanks.

I have just one objection; shortening the spreaders is definitely a NO-NO!

If this was done in ignorance, then please be informed:
By shortening the spreaders you are altering the angle of the shroud in a non-favourable way. If we analyse the force the shroud exerts on the mast into one horizontal force and one perpendicular force, by shortening the spreader you are increasing the perpendicular force and decreasing the horizontal force which is what is keeping your mast up.

I strongly advise against shortening the spreaders!!! You will only be weakening your rig.

Increasing the chances of a mast failure is not an acceptable tradeoff for ease of handling when the mast has been lowered. Safety should always come first.

Hope this helps.

Octaman

Hi,

Thanks for the warning on shortening the spreaders. Before I did it I obtained Brian Toss's book on rigging and did the math, since I'm only a backyard engineer. The original spreaders on the X are 44" I believe and the D & S models use the same mast as the X and they are 36" go figure. I know of 3 Xs that have shortened the spreaders and no problems have occured that I know about.

With the original spreaders I had a general failure, that could have easily been a dangerous experience. I spent 3 days at Mead with high winds day and night. There were 3 of us in X boats and we de-rigged at the same time. When lowering my mast both spreaders FELL off at the in-board end, where they were severed at the point they emerged from the mast fitting. The factory replaced them and I still have them since I later shortened my originals. I deburred the fittings and check them yearly and there are no problems. The point is that the long spreaders are not somehow sacred or any safer.

As a trailer sailer you can make life easier on yourself anyway you want. However, in general, everything you add to make something else easy, or supposedly safer, comes with a expectation of extra work of it's own or just a 'little downside that you can live with'. Good luck with that. I will enjoy passing you in the parking lot or on the water.

8 inches off the 44 inches sounds like a lot percentage wise, but the change in angle ( which will be proportional o the change in mast force will be much less..I'll SWAG it at about 2%....

I calculate the exact delta when I have CRAY time later this week, Boeing has it tied up this week trying to figure out how to keep the 787 from catching on fire ....

Hey Newell,

I am sorry to hear about your spreader failure. A good thing you didn’t lose the mast!

I have to point out that I don’t believe spreader length was the reason for your severed spreaders.
If you bang around your spreaders when shifting the mast forward or aft in the horizontal position, or if a shroud gets caught onto something while moving the mast (as often can happen) and you pull on it, you can very easily bend the aluminum spreader at the inboard end where it connects to the stainless steel mast fitting; even slightly that you do not always immediately see. This will eventually lead to breakage, regardless of the length of the spreader.

The aluminum pole (spreader) can withstand great forces exerted parallel to its axis (compression) but is quite fragile when you try to bend it. Aluminum is a softer metal and it will break with relative ease. Also, great care should be taken not to apply any kind of pressure to the spreaders when the mast is down and you are moving around them.

Another important point is to be sure the outboard end of the spreader, that clamps on to the shroud and has no freedom of movement when tightened, is resting at a neutral point, as the mast comes up, where it is neither forced to go higher (or lower) relative to the inboard mast fitting. When the mast is eventually all the way up and the outboard ends of the spreaders are not tightened in the correct position you are forcing the spreaders to bend; this will again result in material fatigue and the spreader will sooner or later fail.
This applies to the Mac that does not have a hinged spreader base on the mast, as most other sailing boats do with a more conventional rig and therefore the outer ends have to be set right from the very first time the mast goes up.

The initial positioning and tightening of the outboard ends of the Mac spreaders is VERY IMPORTANT for the longevity of the spreaders.

Hope this helps.
----

No chance of bumping into you at the parking lot or on the water; we are an ocean or two apart! And that is something I miss, not having other Mac owners around me. There are very few here in the entire country, so I very rarely see one. Thanks to this forum, it doesn’t get so lonely . . .

Happy sailing!

Octaman

Don't use lifting system, since mast is light (I am 69).

I envy you too as both shoulders are stuffed from many years lifting and climbing (sparky) but probably could except for the fact my mast is fully loaded with boom and all sail hardware mind you don't know how you clip the jib on without help as even with the raising winch it's fairly tight, at the end of the day though why bother struggling or risking dropping the mast when it is so easy with a lifter
Ah see you have an so the shorter and fixed mast is probaly easier.

Catigale wrote:8 inches off the 44 inches sounds like a lot percentage wise, but the change in angle ( which will be proportional o the change in mast force will be much less..I'll SWAG it at about 2%....

I calculate the exact delta when I have CRAY time later this week, Boeing has it tied up this week trying to figure out how to keep the 787 from catching on fire ....

I sketched this out with a Crayon, which is about as close to a Cray supercomputer I'm ever going to get.



The geometry is an approximation, based on what the various drawings show, the sail dimensions, and what (little) I can remember. All members were treated as two-force members (wires and rods, with pin joints with no moment capability), and I only put a single lateral force F at the top, rather than trying to model distributed sail forces along the mast and such. I don't remember if the spreaders are actually up-swept, but the difference would be in the noise. And of course, the real rig is a 3-dimensional structure, with swept-back shrouds, and a forestay. I don't have enough ambition to model that right now.

But it IS instructive in how the shroud and mast loads increase as the spreaders are shortened, as you would expect. A lateral force (F) at the top node translates to 6 times that at the chain plates and mast tabernacle, with a 33% increase in load on the lower part of the upper shroud and a 17% increase in chainplate and tabernacle load when the spreader is shortened 8". Spreader compressive load is decreased about 6%, though, as is the inner (lower) shroud loading.

It's also interesting that the upper and lower shroud max loading is essentially the same at 3.36F until the spreader is shortened, at which point it jumps to 4.05F for the upper and drops to 3.16F for the lower.

OK, so I find this sort of thing interesting. Not everyone does.

And if anyone sees a math error in there, please issue a slap to the back of my head, intensity proportional to the severity of the error.

Has anyone ever made a combo "bow sprit"/"raised mast carrier" I am trying to think of some item, that I can use as a bow sprit, maybe something that I can eventually hook a spiniker roller fuller in to, or at least fly the spin off of. Then, when trailering it is used to hold the mast so high, that I don't have to feed the spreaders under the life lines.

Any one able to envision what I am talking about?

I know exactly what yer talking about... an elaborate solution to a simple problem.

Simple solution ... Quick-release lifelines. Or remove the laundry lifelines altogether and forego their false sense of security!

I sketched this out with a Crayon, which is about as close to a Cray supercomputer I'm ever going to get.

That's a nice definitive piece of work! You must have used a 64bit crayon.

R.

I wonder where I Charlie-Foxtrotted my SWAG? Unfortunately it was under my glass of red in FC, and was taken away by an absolutely smoking hot FA on Delta, so I cant see the back of the envelope....