Spreader set-up

I don't know about process pics but I did start a bit of a discussion about it HERE

Or are you talking more specifically about adjusting the spreader turnbuckles?

I think that will do it!

Thanks.

That thread is certainly in the same general area. Let me pose my question as i was writting it and taking pic;s as Tikipete sugested. (I don't know how to put attachments into the text)
Dear Forum,
I need help understanding the measurements for Blade spreaders. Attached is the text in the assembly manual, and a pic of how I have the spreaders adjusted now. As I understand the directions the tips of spreaders (where the wires go through) should be about 27 ½ inches apart, which is how mine are adjusted. But the directions also say that the distance between a straight edge between tips measured to mast should be 1.5 inch. Mine is about 3.75 inch. I can't see how these two measurements can fit together.?.?.?.?

and the photo

Make your post and submit it complete with the attachment. Click on your attachment when you are back at your post. Select the address in the browsers address bar and copy it (ctrl-c or right-click or edit-copy. what ever grabs you).
Go back to your post and edit it. The instant UBB code allows you to post an image. Insert the copied address (ctrl-v etc). And there you have it.

Measured mine in the dark, so this is somewhat approximate. Wire to wire I have about 28.5 inches width. I have extended the spreader arms to better keep the mast in column. Straight edge over the wires, I have about 2.75 inches - which is too far. I am going to adjust back to 2 to 2.25 (too much prebend, with lots of diamond tension). It looks like my adjuster arm is threaded out further than yours (the piece that changes the angles of the spreaders). I measured the

blue

part of my spreaders from the bolt by the mast to end of the

blue

part and it was approx 13.25 inches. Could your arms be longer? Let me know if this makes no sense.

Matt mentioned lenghtening the spreader arms to me.

btw, one end of your straightedge is not resting where the diamond wire would be, if it were there. I'd rig the wires then make adjustments.

Tsham,
Well I think you figured it out. the blue link of my spreaders measures 14 3/4 inch from pin by mast to end of blue link. I would think the point would be to keep the same angle but use less tension on the wire. Did Mark indicate what his thinking was reguarding the change in lingth?

Will, if you want the same set-up as the manual, and Tom wants longer arms? Why don't you just swap arms? <img src=

alt=

/>

Actually, I've been doing some thinking about the spreader width/rake/diamond tension on the Stealth mast. I felt that I was using a hell of a lot of tension to achieve the desired pre-bend, as a result the mast was under very strong compression which meant that it could S-bend easily and move out of column.

I'm hoping I've solved or eased the problem by replacing my Stealth spreaders with a pair of Tornado spreaders that I had in my kit. The overall width of the arms now is almost 3" more than it was before and I've been able to ease off the diamonds a huge amount but still have the right pre-bend. I think this is going to be kinder to the mast (and, hopefully, faster!)

Will,

The distance between the

straight edge between tips measured to mast (1.5 inch)

is by far the most important adjustment. If you have to choose then make sure you have this set right and just accept any distance between the arm end tips that results.

Personally I feel the 27.5 distance quote is a typo. 28.5 is far more like it. From memory all new F16's except Stealth are using 390 mm long proctor spreader arms. These can not be set at 27.5 without seriously increasing the distance between

straight line and mast

I think my 390 mm spreaders tips are 29 inches apart. I'm running 2 inches of

straight line mast

distance.

Wouter

This was sent with my assembly manual as an addition.

6.1 – SPREADERS
Set up the spreaders as indicated in the mast assembly section. The
following are setting adjustments for longer spreaders provided.
The spreaders provided with the new boats are cut to 15” in length. As an initial starting
point we have been running the adjusting arms in and setting the diamonds at
approximately 2” of rake when measured across the mast. Tightening the diamond wires
to set the prebend in the mast at approximately 1 ¼” .
Note this is a mast tuning adjustment. The prebend is critical to the fit of the sail to the
mast. Some adjustment from this range may be required to get the sail shape you desire.
The spreader width, amount of rake and diamond tension are adjustable to taste and
conditions. The mast while sailing should remain in column. Please note while sailing if
the mast bends to leeward, you have too much tension in the system, and if the windward
wire becomes loose while sailing the diamonds are not tensioned enough. Either of these
conditions could cause permanent damage to the mast.

This doesn't mention the tip to tip length. It just specs out the 2" rake. Note the reference to longer arms.

The original spreaders fit the T4.9 class limits, but Matt found better results with extending beyond those limits (since it was not a F16 limit). He probably just started ordering the longer arms (maybe?) to meet the better performance. The reasoning was better ability to keep the mast

in column under load

. I guess, the wider arms better keeps the forces on the mast under control.

I would not think the spreader width would be a problem (within reason). Most important is diamond tension and spreader rake which results in prebend affecting sail shape.

John,
Have you any way of determining the angle between your two spreader bars? I did some measuring and estimating and then dusted off the old trigonometry and I think the angle that Tom is working around and instructed to arrive at by the instruction book is about 63 + 63 degrees or 126 degrees. My plan is to duplicate this angle with my longer spreaders. It would be great to know what Stealth is using for their spreader angle.
Will

I'd have to go down to the boat and lay it over to get that info for you. I'll see if I can remember to do it this weekend.......

John,
no that's okay. I'm stringing the wires now. I don't think i can get it as tight as the book says. On those spreaders i'm using 29.75 inches instead of 27.5 inch between the wires and 2 inches to the luff track.
Thanks for your input.
Will

Gee i missed Wouter's, BobCat's and John's posts. I guess i foregot to turn the page. (Me, not the master of the obvious).
so I'll step back again and go foreward. I must be getting close.
Will
Bobcat's special instructions kind of spell it out!