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Rig Tune (Again)

PostPosted: Tue Feb 03, 2009 9:30 am
by Motorboat!!
Alright, I know there has been some discussion of proper rig tuning here (there was even talk of a tuning guide). My questions are:
Mast pre-bend; who has it, and how much?
Does anybody have the mast raked back at all?
Are there any decent Loos gauge #s out there?

Re: Rig Tune (Again)

PostPosted: Tue Feb 03, 2009 10:52 am
by Pterobyte
Musicman has what appears to the real data on making this boat go. See:
http://nbayracing.com/Evelyn32-2Forum/viewtopic.php?f=3&t=42&p=351#p351

So far, unless I hear different from John, Musicman, I have mast step forward, +2", pre-bend blocked forward to max of the cabin top hole. We need to check this position though to see if it is in the right place.

John suggested tightening the the shrouds to max loose gauge, back off the lowers 1 turn for light air. That's it.

John, did I repeat this correctly?

I don't have the E lengthened like Remedy or Bluto so I am still at 96. I will probably add a new main with a larger E and longer boom and add a new #4 to our inventory next fall. Too much boat work being done now to get both done at the same time.

Re: Rig Tune (Again)

PostPosted: Tue Feb 03, 2009 5:18 pm
by musicman
Sorry, I haven't gotten around to writing a guide. As for pre-bend you should have 0-.75" Don't assume all maststeps or partner cut outs are the same... So, the way to start is get the headstay length right first & adjust the step & partners to the 0-.75" of pre-bend.
As for rig tension, yes we sail at pretty much the top of the gauge all the time except in under 8 where we loosen the lowers 1 turn.
I'm sure this sounds like a very tight rig, well it is. The reason for this is that the boat it fastest & points best with NO "sag" in the rig. Sag helps power up the main, in the case of the 32 the stock main is SOOO small that there is little gain in doing this. All that ends up happening is the slot is more closed as the main gets closer to the genoa. Some of this is also exaggerated by the size of the genoas & the fairly short spreaders & narrow shroud base width (compared to something like a J 29 which is very fast when tuned with "sag").
The long E is a no brainer on these boats, a gain all the way around the course. Another benefit is that it makes sail selection easier, you can sail down range much better with a #3 and big main. You do need a #4 with the long E though.

Re: Rig Tune (Again)

PostPosted: Wed Feb 04, 2009 9:41 am
by Motorboat!!
Thanks
Thats very interesting that you have almost no prebend. I was looking up my mast the other day and it seems like we have maybe 2-2.5" of sag. When we race, regardless of the wind, the runners are almost always tight, as well as the backstay. It would be nice to eliminate some of the prebend though.

Re: Rig Tune (Again)

PostPosted: Wed Feb 04, 2009 10:43 am
by musicman
To be clear "sag" is side to side, not for & aft (mastbend).
While we have Zero pre-bend we can see up to 5" of mastbend is some conditions while racing.
One very important thing to remember is that unless your mainsails are designed for 0-.75" of pre-bend they will not work with this setup...
In know it must sound like I'm trying to sell sails with that one...bit it's the truth.

Re: Rig Tune (Again)

PostPosted: Tue Aug 31, 2010 10:28 pm
by olds_corpion
Reading this forum got my Evelyn juices flowing again, so I thought you might be interested in this...

When I had my boat in around 2000-2001 we had 7 Evelyns racing together on Lake Erie. At the time, I took LOOS guage measurements from 6 of the 7 boats. The 7th (call Brigadier) was never very competitive, so I didn't measure that one. Anyway, here are the measurements:

Boat Uppers Intermediates Lowers (Forestay) Pin to Shiv
Wildthing 36 23 30
Patriot 37 23 28
Cartel 35 23 27 40' 9"
Bird of Prey 39 24 42
Fever 37 24 33
Scorpion 37 23 28 40' 7.5"

Note, the forestay measurements (only 2 shown) were taken by running a tape up to the top of the mast on the jib halyard, so the measurement is from the pin on deck to the shiv at the top of the mast. So, it appears we sailed with our forestays a bit longer than most of you do. I had two toggles on the end of my forestay (Scorpion).

Also, we generally sailed in 5-15 knots of breeze. We sailed with significant headstay sag in the really light stuff as you can see in this photo.
http://www.countryandcoast.com/bucc18/PA010437.JPG

Just for fun, here's a pic of us leading a couple other E32s around
http://www.countryandcoast.com/bucc18/PA010305.JPG

Re: Rig Tune (Again)

PostPosted: Wed Sep 08, 2010 9:58 am
by musicman
Interesting headstay length numbers you have there. We used 40.5 as a base on "Remedy" (40'6") which generated quite a bit of rake (see rake photo below).
One thing I've noticed from boat to boat is the I dimensions vary, your old boat has a 3" greater I than "Remedy" did. This would expalin why you needed a longer headstay than our base number. I think quite a bit of this comes down to repaired/rebuilt mast steps.

Here's a shot of our minimum rake setting in 25 knots:
Image

The advice of sailing with alot of headstay sag on a 32 is not fast. Given the size of the headsails & their proximity to the main when fully trimmed you need to work hard to keep the slot open. Looking at your photo there's far to much sag & volume in the headsail for the windspeed (to much sag overall as well). A telltale sign of this is the main being fully inside out.
Look at this photo, take note of the: headstay sag, mainsail & genoa volume & heel angle.
Image

Re: Rig Tune (Again)

PostPosted: Fri Sep 24, 2010 3:02 pm
by Motorboat!!
So I finally measured my headstay this week, and came up with significantly smaller measurements than discussed here. Measuring all the way to the deck, My measurement was only ~39'6". After noticing that I am almost a foot shorter than most others in this thread, I loosend my headstay as much as I could, which was still only about 1/2". Can you but a longer threaded toggle bolt for the headstay? I am curious to see what change this will do to my boat.

Re: Rig Tune (Again)

PostPosted: Sat Oct 02, 2010 11:21 am
by mal624
I know on my old boat (hull 2) the headstay was lenghtened about 8" to get to the numbers above and get the proper rake. It makes a significant difference.

Re: Rig Tune (Again)

PostPosted: Sat Oct 02, 2010 10:34 pm
by musicman
Motorboat!! wrote:So I finally measured my headstay this week, and came up with significantly smaller measurements than discussed here. Measuring all the way to the deck, My measurement was only ~39'6". After noticing that I am almost a foot shorter than most others in this thread, I loosend my headstay as much as I could, which was still only about 1/2". Can you but a longer threaded toggle bolt for the headstay? I am curious to see what change this will do to my boat.


The boat will have much better pointing ability with the correct headstay length. You can experiment with it by using link plates, however you may find the clew heights of your existing sails to low at 40.5'.
I can help you with that...
John Fries
Evolution Sails
Mystic, CT
860 536 4235

Re: Rig Tune (Again)

PostPosted: Thu Nov 27, 2014 5:56 am
by toddkyle
It's all outlined in Barney's Complete Guide to Albacore Sailing, available to USAA & CAA members. Or you can look at the Speed Sails tuning guide (which I don't think is as comprehensive as Barney's guide, but answers some of your questions) See http://www.speedsails.co.uk/docs/Albacore.pdf

Basically, you set the rake before going out and then adjust rig tension depending on conditions and point of sail.

More rake helps depower the boat, less rake means the mast won't bend as much so you'll have to hike harder to keep the boat flat. More rig tension makes the jib luff flatter (less sag) and this helps the boat to point, less tension allows the jib luff to sag off to the side, generating a fuller sail which give more power at the expense of pointing. So, light winds or downwind work call for less rig tension, higher winds and when beating call for more tension. As you become more familiar with the boat, these things can be adjusted for feel - if the boat feels slow, ease the rig tension, if you can't point, try tightening it.

The vang (or the Kicking Strap as they call it in the UK) has a large effect on rig tension, and if you've set the rake and spreaders appropriately, simply apply more vang as the wind picks up - at first it'll help power up the boat by bringing the leech into line, then it powers the rig down by flattening the sail.