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Mast hardware questions


acreew

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Hello,

Feeling my way through mast assembly with little knowledge of hardware:

1. What does the snotter attachment look like? How is it attached to the mast?

2. I have 2 metal S hooks (with one end closed) included in the mast/Sail hardware....what are these for?

3. For the blocks at the top of the masts...the top holes are to be attached with " 1" 10 PH screws"...does the 1" refer to the length of the screw? Also... assuming these are attached with nuts/lock washers?

4. One cam cleat has the keeper....which cam cleats go where?

 

Thanks for any help, suggestions, pictures. 

More questions to follow I am sure.

 

Will

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Hey Will,

 

Sorry for the confusion, we need to do some hardware and rigging videos badly for the CS boats. There are some good pictures of hardware setup of a CS15 in our google albums. The setup is still relevant with some minor differences for the CS 17. Link here.  https://goo.gl/photos/ArRenwLh7wZF1Fxb8

Some pics of snotter attachment like this one. https://goo.gl/photos/wgAtub3ibvtPM9or8

 

2. S hooks are used for the downhauls and for the snotter attachment. downhaul hooks hook onto the tack grommet of each sail and make for a 2:1 purchase on the downhaul. If the 20mm blocks aren't already on the hooks, they're meant to be. http://bandbyachtdesigns.com/how-to-put-a-block-on-an-s-hook/ 

The snotter hooks hook onto the snotter eyestraps that are to be bolted to the fronts of the masts. 

3. 1" is the length. The lower holes get a bolt and lock nut. the top holes can use screws because they will screw into the mast cap. 

4. The keeper is meant for the halyard cleats for the main and mizzen so that the halyards don't recleat when you're trying to lower the sails. 

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re " 1" 10 PH screws"...

 

As Alan said, 1" is the length, "10" is the screw shaft diameter size (vs 8 or 6, both smaller), PH means pan-head (head above the surface), as opposed to FH or flat-head (countersunk, head flush with surface).  Thanks for fotos, Alan. 

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I also saw a setup, where there was an eyestrap on either side of the mast, woth a short loop of line going between.  The snotter rig had a snap hook on the block.  The slight advantage to that is that the load on the eyestrap screws would be in shear instead of tension.

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Don, those screws in the photo aren't in shear, they are mostly in tension (which is generally what you want with a bolted joint).  If that blue-flecked line were wrapped all the way around the mast instead of doubling back over the sharp edge of the eye-strap the line would last longer and the screws would see less load.

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I agree with you about the line wearing on that stamped eye strap.  I would have used a formed wire eye strap for this application.  (This photo was of someone else's boat at a messabout a couple years ago.). 

 

I disagree with you about shear loading.  The pop rivets on the mast are under shear load, mostly.  Depending on the orientation of the sprit, the cheek block could be under shear or tensile load, or a combination of both. I don't like tensile loading of screws in wood (unless they're thru-bolted), because you're depending on thread engagement to take all the load.  A shear load is less apt to fail, I believe.

 

And if the screws of that cheek block are under tensile load, a cheek block is the wrong block for the job!

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Here's an online calculator that can shed some light on the topic, at least for screws in wood.   It's from the American Wood Council (whoever that is).

 

http://www.awc.org/codes-standards/calculators-software/connectioncalc

 

I ran a couple of calculations for a 1"  #10 wood screw connecting 20-gauge steel to "mixed southern pine."    

For shear load, the ASD capacity (whatever that is) is 115 lbs.

For pull-out, the ASD capacity is 95 lbs, which is basically the same.  Agree to agree?

 

Having the line go around the mast will take a lot of the load off of the eyes.  With the line around the mast, all the eyes do is to keep the line from sliding up and down the mast. I'm going to use something like this for my mizzen.  The primitive snotter I tested this morning turned out to be a pain.

 

Bob

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Since my sails are attached with luff sleeves, my snotters go around the mast.  This won't work with a sail track, hoewver.  If I had a sail track, I would put an eyestrap on either side of the track, aft of a line across the beam of the boat.  I'd tie on a short piece of line, a sort of short bridle and not a loop,  with stopper knots facing aft.  I'd use a double overhand stopper knot (http://www.animatedknots.com/doubleoverhand/index.php?Categ=typestoppers&LogoImage=LogoGrog.png&Website=www.animatedknots.com#ScrollPoint) instead of a figure eight.  On my snotter rig, I'd have a soft shacke attaching the snotter block to the bridle.  This would eliminate a lot of clanging and scraping that comes with hooks, clips, and unnecessary stainless steel.

 

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I rigged my little mizzen* today, and here's how I set up the snotter.  There's a single loop around the mast, held up by an eyestrap on the aft side of the mast.  The block is lashed to the loop with some fine high-tech string, and the end of the snotter is also anchored to the loop with a bowline.  The line line goes through a smooth hole in the sprit off the left side of the photo, back through the block and down to the cleat.  

 

Bob

 

592a03c80bcad_snotterdetail.jpg.2690469c03efc33bbfd97e9ae5e8ccee.jpg

* it's a little mizzen because I have an unconventional sail plan.

 

 

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