length of spreaders

[ebb]

Decided years ago I wanted airfoil spreaders instead of broom handles.
Also the aluminum sockets and the four thru-holes for the 1/2" bolts were a royal mess.

So recently in cleaning up the mast, the sockets long gone, closed up the top 1/2" holes.
And more or less where the tube spreaders had been, cut in rather wide oblong horizontal slots for the bar that slides thru the mast that these particular airfoils slip ONTO.
A totally different method of spreader attachment - for sure.
And right below the eye shaped holes I left the orignal bolt holes that the lower tangs where strung on to. But

the original spreader sockets where put on really crooked, one side lower than the other. So I decided to incorporate a larger diameter compression tube that got the east and west holes to line up by drilling out the 1/2" holes with new 3/4" that are 1/4" lower on one side, with the other side 1/4" higher. Much betta line up now.
That's not important here, except that the mast now has a group of four rather large evacuations pretty close together in the middle of the mast.

Plus the new airfoils have beauty plates upon which the spreaders bear against to protect the mast - and they will be screwed or popriveted on thru 6 more holes EACH. ebb's wondering what he got hisself into? Thats 16 holes plus the two plugged ones, which are still holes as far as the mast knows. 18 holes in a dead mast's chest.

There's still the rub:
Had to check on the length of the old spreaders which have mysteriously disppeared. Going to the drawing on pg 146 in the Manual. which features the Ariel's sail plan, we can see that the spreaders hold the shroud out from the mast at exactly the width of the boat. If the boat is 8' beam, which it is, then each spreader is 48" long minus half the width of the mast. Mast and upper shrouds are precisely parallel from mast base to spreaders.

Then I measured the new airfoils. The particular extrusion is obsolete. In fact Buzz Ballenger recently found and sold me the last set of beauty plates that I'd missed getting when I bought the system.... That he obviously had been saving for me.
The new spreaders measured 36" long. WHOT the HELL? ! ! ! !

So I called up Ballenger Spars and asked Buzz if he knew what I was going to do?
....Brain calculating what custom spreaders might cost in 2012? Plus whatever a new bar extrusion was. Wasn't going back to sockets and tubes.
So Buzz on the other end of the line says,
"Let me do a little figuring. You need a 12degree angle," he said mysteriously....silence....
What 12 degree, I asked. "Angle of the shroud to the masthead," says he....silence....he working off original Ariel plans that he has on file...
...."No problem." What's no problem, I ask.... you mean I can use the shorter spreaders?
"Yup." OH!
No drama!
Thanks, Buzz!!!

So there you go.
My first thought is what that may do FOR the 100+ size jibs and genoas that litlgull will fly.
This bit of drama should be confirmed with an architect. Who?
So don't go out right away and shorten your spreaders.
But it's something to think about.
Right?

[Rico]

"... cut in rather wide fat horizontal holes for the bar that slides thru the mast that airfoils slip onto."
Right?

Hmm... Ebb, you've now created a scenario worth looking into in detail; I'm not too worried about the spreader lenght here... I'm more worried about the amount of metal that is now gone from a point in the mast that is essentially just where the greatest amount of bending moment occurs....

How big are these 'eye' holes exactly? and where are they relative to the other holes in that area?

Picts perhaps?

[ebb]

Tony,
Yeah, I've recorded every step of the way with photos. Have a friend here who may help me post a current pic. The OBLONG slot holes in question are horizontal of course. About 1.375" long, about .375" wide in the center of the slot, and at the ends about .250". They actually are slightly larger than that and we might describe the shape as sort of like a Butterfinger bar if the bar was also slightly rounded on the bottom like the top - but smaller. Unless they've reduced the candy size like everything else these days. A Butterfinger bar is a six decade old memory!

The area of a 3/4"D hole is what? about .44 of a sq inch? The area of the slot is, guess, about .55" - maybe a skoch more. The slots have two inches of mast metal between them and the 3/4" holes below, which is where the tangs were hung from the bottom bolt of the original socket. And will still be in that location.
The now filled in top bolt holes are 3/4" above the slot cut out. Slot needed the separation because of the large s.s beauty plates.* Couldn't have them fouling the washers and tangs of the lower shrouds.
Am worrying about these (SIX, old and new) large holes being too close together. The actual placement of the new spreaders compared with the old has the new airfoils slightly above the original tube spreaders. Of course the old ones had the point load spread by the mass of the socket casting.
I'm struck by becoming aware that the spreaders are in the exact center of the mast length, almost exactly!

Radius of the old sockets to the mast was not a close fit and some kind of hard black bondo type filler was used to fill the gaps. I saw no wear in any of the parts - like the tubes in their sockets were not worn or deformed at all. Even tho the install was very funky. One socket was about 1/2" lower than its partner on the mast AND ALSO slightly skewed! (It's not unusual...to be P...d with Pe...ar...son...whoa-oh-oh-oh-oh!)

We do have the four lower shrouds on our boats with a nice spread to them to help keep the mast from bending. And they just happen to terminate right there at the same spot the holes populate! There could be a scenario where the mast would want to fold at that point/joint. I wouldn't know how to estimate the stress those holes are under - or what will happen there if a shroud or stay failed. Have the one hero compression tube (more correctly described as pipe because of its 1/8" wall) so the loads of the lowers there can't deform the mast section INWARD when the going gets tough. And the lowers will be stressing the 3/4" holes downward - but we have added more good bearing surface on the aluminum wall with greater diameter pipe!

The feather light spreaders fasten to the solid thru bar by sliding on over it, like a Butterfinger wrapper, and get thru-bolted to the bar. The rather delicate section of the foils will bear on proportionately large s.s. load spreading plates.* But that's the method the airfoil spreader gods designed to immobilize the assembly. We can say the assembly uses opposing mast walls to keep centered. And assume the bar with the spreaders bolted on will not allow the mast to deform inward. We can describe the compression tube and thru bolt with its shroud gear on it as doing the same - but more unlikely to ever shift. It is symetrical rigging pressure on the mast that keeps the mast straight.

But if the uppers are tuned correctly the pressure on the spreaders should be pretty equal on all points of sail. Unlike the lowers Right?
Not totally sure about this, but the uppers are compliments of the stays and shouldn't sag or be loose if tuned correctly. The mast can bend when the lowers are loose on one side when beating. Actually the mast can bend if the windward lowers are looser than they should be. The lower stays together help keep the mast from bending too much from the downward pressure of stays and upper shrouds.
Imco the slot holes are NOT under any stress. The bar is prebent to the equalizing angle the spreaders are supposed to be at. (Though in the spreader's NEW shortened aspect the bar's prebent angle may have changed and I may have to get/make a new one if the bar can't be altered.)
What the dynamics are with this thru-mast spreader system, haven't a clue. Hope there are NO dynamics, that it's quiet and static.

* the plates are precurved 3.375" X 2.375" well-rounded belt-buckle like shapes generated from the slot profile. Six 7/32"D fastening holes are aprox evenly spaced around the perimeter. The center cut-out for the bar is a bit more crudely done (laser?) than the plate which is nicely shaped & finished. $$ 16 gauge polished s.s of unknown pedigree and came to me with 20mil pipe wrap already applied on the concave side.

See what I can do about getting a photo of the holes here. Really want your take on this little problem! Thanks!


Here's a toast (currently Moylen's KiltLifter) to the new SHORTY SREADERS. Buzz is as close to a spar god as litlgull will ever come!
Here's to the mysterious twelfth degree.... and Here's to the good elf Seran Dippidy!

[Bill]

Take a look at posts #9 & 10 on the ARIEL 100 restoration thread:

http://www.pearsonariel.org/discussi...00-RESTORATION

Appears that Svendsen installed air foil spreaders when they redid the rigging on the boat. Maybe they have some documentation.

[ebb]

Thanks Bill,
Ah, YES, Beautifully documented with a host of your great restoration photos.
Ed Burke did the honors for Orinco Flow.

His airfoils sit in sockets.
With new sockets 'customed' no doubt to the existing pair of holes thru the mast. Thereby not weakening the mast - if indeed the A/C mast is weakened with the extra holes as ebb has done.

Rico is the only engineer and sailor that I'm aware of, who has also documented our upgrade of the same area on the mast,
and added a compression tube to insure that rigging forces can not deform the mast there.
Wonder if Svendsens added that hidden feature?

Rico has closeups of how a compression tube is added to the mast as an upgrade. Mephisto Cat, page 5, #87.
I'm unsure whether Rico tubed both holes. There's a bit of weight to consider if your tube is 1/8" wall s.s. (about .205lb for one piece.)
I can imagine a spirited breakfast discussion on the merits of whether such heavy wall is needed and if aluminum tube could be substituted.
It's only 3 1/2OD across the mast. Any tube in there that short couldn't be expected to deform with thinner wall especially with a close fitting 1/2" bolt inside it.
Litlgull's mast has the same weight s.s. tube as Rico's and also the airfoil BAR weighing in at .65lb for a total of .855 of a pound. Pretty considerable.
Only mention this, hopefully to create controversy, these are after all the "Discussion" pages!

In fairing the mast to repair and prep for painting, I use a product called LabMetal - an aluminum powder filled onepart epoxy autoshop paste.
A-338's mast really showed the years. I ended up using the paste for fairing on the aluminum. Not something I"ve done befor! But it seems to have worked, it feathers well into the mast metal and seems stuck pretty good. It is slightly different in color when sanded.
The mast metal gets bright, the filler stays dull. The masthead is dull with filling BUT
the middle of the mast is all shiney. 45 years of who knows what possible damage could have happened DIDN'T.
The only dull spots are the 'coins' where boltholes have been disappeared. All bright aluminum where the crooked sockets were.
The mast wall section as pristine as when first extruded!

For them into racing and at all costs keeping the weight down, you can use bolts alone, NO pipe, to create the anti-compression effect by buying bolts that have a portion of their shanks NOT threaded.
It's a bit picky but more correct to protect the nut side of your mast hole from sharp bolt threads by getting longer bolts whose shanks will span the distance and bear unthreaded on both walls of the mast.
What I propose is a bolt with a very short thread - used only for the nut that is tightened to refusal against the end of the threaded portion of the shank- all the buried part and what is taken up by tang and washer is on smooth shank. You'd probably need a die to tweek the exact amount of thread. Or add extra washers. So, if you make it impossible to tighten and squeeze the mast walls, no compression tube is necessary, imco.

Always a trouble maker. "....by the slack of the ebb."

[Tony G]

There's always another way of doing something. Sometimes marginally better than others and this may be one of those instances. But I can't imagine, Ebb, that your mast is truely any weaker, at least to the point of failure. My uneducated rational is that our spars are notably oversized compared to...comparable boats...if that makes any sense.

Of course we know that cyclical loading and stressing will eventually lead to failure. And it seems in this case that the weakest point coincides with, or very near the point of most flexing. Do you thinks with the stays and shrouds properly tensioned there will be that much movement? Movement yes. But I gotta think in situations that pump the mast that much you are going to be so uncomfortable you'll adjust course or change something to alleviate it. Look at all the examples of less substaintial masts out there still standing. I think there are some Westsails out there cruising with wooden spreaders still! Crimony, man,you have a top notch stick there!

[ebb]

Howzitgoin Tony?
Obvious I'm fascinated by methods, techniques. It's the stuff we think we invent that we get off on. How-to-proceed for the out-sider is usually not explained very well - or is unexplainable. Experience, intuition and concentration seldom sees words. The refuge of the master-shipwright is instant gratification in seeing his task already completed. In his mind it is done. He's too impatient to explain it and never will spend half his life on the internet looking for advice - or how to re-invent the wheel - or even a better way to do it. The next step for the guy who is really sure is simply to dance. That's why I'm so damn slow.
There is always somebody who has done it, whatever, befor - done it better and with effortless agility. Knapping comes to mind. Hitting one rock with another to make a point has been the difinition of what humans are for millions of years. That vital skill in countless generations had masters as well.

Those who didn't have the knack wanted to sit close to the master knapper. That produced social organizing, secret societies, family trees, conflict, governments, corporations, privilege, war, cults, benevolent associations, and blogs. Making it possible for people who didn't have THE skill, or any skills, to have something to do, and maybe something to contribute.


That sheeve bolt at the top of the old mast - where on A-338 most of the aging occured to the mast structure - imco can be upgraded with the smooth shank cross over and enough thread only for the nut. That's what I'm doing. The mast shows with the LabMetal fairing that the original bolt did deform the mast sides permanently inward.

Without forethought I had a new 6 11/16" delrin sheeve made with a bronze bearing for the usual 1/2" thru-bolt. It is possible to imagine a compression tube with a bearing sleeve around it, but I didn't see it, and missed the step. That single double duty bolt which also anchors the upper shroud tangs could use extra help in the form of bushings for the mast wall. May still do that, but haven't planned on it. Stainless steel or aluminum bushings for the mast wall would have to be customed, so I may leave that fat chance for the future.

Instead of merely loose cheek pieces the original 6"D sheeve installation had, I'm putting it in a welded aluminum sleeve, which I hope will help stabilize the top of the mast. To form a sleeve the cheek side pieces are welded to top and bottom strips. The new sleeve, in that amazing huge mast cutout, will be flat and solidly resting on the bottom of the cutout, helping to resist the downward pull on the bolt. The old side pieces were held in place only by the bolt passing thru !
By boxing the assembly the sleeve can be considered a structural component and can also be fastened to the mast with angle clips if desired.

Hopefully the short thread no squeeze bolt, as described, will work as imagined. Not only does that lone bolt hold up the mast with tensioned shrouds, but also holds up the mainsail with all the added downward force of bar-taut halyard. That's a lot to ask of 1/8" aluiminum wall!

[Tony G]

it's goin', Ebb. Too much work not enough play.

I hope you don't think my response was flippant or without realization of the enormous amount of time and thought you put into your projects. I have more than once benfited from your research. And I have been jaw dropped often enough watching someone who was a master at their craft. I know my place in this food chain of tallent and I'm ok not getting eaten first.

It sounds like your sheave box will firm things up a lot at the top of your mast. That "fits just right" bolt seems like the perfect companion. I just don't doubt your mast's strength. That's all. I, naturally, put way too much thought into the mast head crane and want to have one built out of plates and welded just to get away from that scarey, scarey casting (which I'm sure will break). I've been googling photos of masthead fittings and cranes for several years now and have not moved forward on it. The perfect companion would naturally be your spreaders. You know I covet those foil spreaders.