Forestay attachment point

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Forestay attachment point

Postby ryderp » Fri May 18, 2012 2:31 am

As I read the rules, the highest attachment point for the Forestay is 56.5" below the tip of the mast. Are most boats rigged with the forestay at the maximum height?

Also, there was a previous post on sail area, but what are the luff and foot lengths?

Phil
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Re: Forestay attachment point

Postby jray » Fri May 18, 2012 9:31 am

Phil, I believe everyone has held as close to the forstay measurement as thay can. As to jib measurements mine is 252" luff, 250" leach and 87" j. It will be intresting to hear what others have done with theirs.
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Re: Forestay attachment point

Postby Chad » Fri May 18, 2012 12:13 pm

The Band 2 measurement is from the original rules which just limited "hoist" height. The addition of a forestay height limit was to prevent going to the masthead and then using a fractional fathead jib- see the current AC45's for an example. The extra 9.5" allowance between the two (originally to keep Joe's setup legal) does allow some extra breathing room if you can raise your forestay to the rule max. Mine is a couple inches below, since the rule changed after my mast was built and I don't have enough carbon that high in the mast to raise it further. I'll have to check, but I think most of the C-Tech masts were built with the jib sheave at Band 2, and the forestay just a little above that.

I don't have sail dimensions yet, just the sailmaker's proposed area. Using that I could probably get pretty close though. I have a bit more overlap than the sail listed on Jeff's PH cert.
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Re: Forestay attachment point

Postby ryderp » Fri May 18, 2012 1:31 pm

Another rig related question: Why is there a difference in P between the class.org rules and the NA rules (285" vs. 295")? Originally, it made sense to have a higher boom for cabin boats to make room for the vang, but with people going to gnav's that's not an issue. Do the NA rule followers find it inconvenient to duck that low on gybes or is the boom high enough?
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Re: Forestay attachment point

Postby Kevin » Fri May 18, 2012 4:42 pm

When my boat was completed and I had trimmed things to length (I conform to the maximum mast length of the original rules), my jib halyard sheave is right at the band thus I can't hoist above the band. And my attachment point is just above the sheave. I expect that any other c-tech rig came out similarly in the end unless they didn't trim it.

From my experience, a 282" P makes for a plenty low boom. That's where my gooseneck is fixed, 3" above the rule maximum of 285" . I have no desire to move my boom lower at this point, even though I am switching to a gnav. Not sure there are many NA rule boats on this forum to comment on the ducking the boom with a 295" P issue. Boom height for the skipper ducking purposes has many factors which are not controlled by the rules. Just a few are.. no maximum forestay length so you can rake the mast back to your liking, no maximum head to clew measurement or max angle luff to foot at the tack.

Kevin.
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Re: Forestay attachment point

Postby Chad » Fri May 18, 2012 10:41 pm

The na folks get under the 295" P just fine. I ordered my mast with a 295" P and haven't changed it.

There's a couple of arbitrary na exclusion rules that serve no purpose other than to exclude na boats, in my opinion. I think these give the fence-sitters the impression that these are nah-nah-nah-nah rules. They aren't things anybody actually cared about before the class split. I always thought the core of this class was that the hull not be made obsolete by shape changes- that is, giving meaning to the "from the plans" clauses of the build rules.

If there's ever a vote to confirm the current rules, I'll consider whether to mod my boat, or just sail my local lake...
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Re: Forestay attachment point

Postby Mist » Sat May 19, 2012 2:14 am

Hey folks this is long lost Mist.

Recently, I had the fortunate experience of having a business trip to Portland OR. I met up with the PDX folks and they had to give me a ride on PDX #1. They are setting up all of their boats with C-tech rigs and P=295. I had no trouble making it under the boom on tacks and jibes. The traveler system and forward end of the tiller were a little further forward than I expected so I had to go around the back of the main sheet. I think I'll set my boat up with a little shorter tiller, the traveler on frame 169, and plan on saying in front of the main sheet on manuevers. I had a great time sailling and socializing with them. Mist will have a cabin and regular vang therefore P will equal 285.
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Re: Forestay attachment point

Postby Mist » Sat May 19, 2012 2:20 am

Someday my math brain will learn to spell! Jibe is really spelt gybe. OOPS
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Re: Forestay attachment point

Postby Mist » Sat May 19, 2012 2:40 am

Additionally, in light and moderate air the PDX boat was very well balanced and when the wind piped up caution was needed to assure it did not inch toward the weather. Therefore, I'm convinced going with p=285 and a little bit reduced mainsail area will not effect perfomance one bit.
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Re: Forestay attachment point

Postby Kevin » Sun May 20, 2012 3:21 pm

Really? We are going to turn this tread into a rules debate? I my opinion the NA rules stretch what was originally legal to have an advantage over boats already built. Anyway...

Mist, I agree with you that the cockpit is tight. If you have a boom end mainsheet and a swivel at 169 it's even tighter. Lots of tweaks I've done to my boat have been to improve that "sticky wicket", if you will. With a traveler at 169 you can swing the tiller extension around the back for tacks and gybes.

To me, this setup is part of the fun of the boat because there are so many options.
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Re: Forestay attachment point

Postby slowpoke » Sun May 20, 2012 7:06 pm

NO MORE DEBATES!!!!!!!
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Re: Forestay attachment point

Postby Mist » Sun May 20, 2012 7:52 pm

No No! I did not intend a rule debate. I was just trying to state a few observations and emphasize that having a p=285, I my opion, is not a detriment to performance.
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Re: Forestay attachment point

Postby Chad » Sun May 20, 2012 10:30 pm

Kevin wrote:I my opinion the NA rules stretch what was originally legal to have an advantage over boats already built.

In some ways, yes of course.

But in a couple ways this class has taken what was legal and banned it. Without showing that these would hurt the class, the founders decided to change P and impose a cabin height rule, despite the gnav option. These both weaken the class, both in numbers and in the court of outside opinion. I'd like to see this class succeed, but I think these short-sighted decisions aren't helping.
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Re: Forestay attachment point

Postby Mist » Mon May 21, 2012 2:12 am

When one has so many gadgets on the boat they become pre-occupied to the point they can't navigate. For many reasons I intend to keep Mist simple. I'll accomplish as many adjustments at the dock as possible during boat setup. No articulating pole, a cabin, and the fewest control lines possible. Lastly, I'm hoping to build the boat for more of the moderate to high wind conditions. Thats when I think this boat will be the funnest.
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Re: Forestay attachment point

Postby ryderp » Mon May 21, 2012 2:32 am

Of course the initial questions were related to the size of the sails (while they are still at the sailmaker). So to be compatible, I'm going with a P of 285" and I'm planning on attaching the forestay just a bit below the legal height.
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Re: Forestay attachment point

Postby Chad » Mon May 21, 2012 2:26 pm

wanti550fl wrote:It seems to me that the real differences between na and this class have nothing to do with one version having any real advantage sailing but by far mostly politics and personal issues. Some in both classes just need to get over it.

You seem to embrace chads wild and cool rig and gybing keel but reject inboard rudders and rounded decks.

Looking in from the outside, it doesnot make sense.

But back on topic, the only reason to use the allowable distance above the band seems to be for an adjustable forestay arrangement ala the ultimate boats.

You raise some good points. I take it as given that the two classes won't kiss and make up- there's just too much bad blood. So unless there's a leadership change at both classes, or one of them becomes defunct, we're stuck with the two class setup. I'd like to see this class do well- it has the people that I have most enjoyed spending time with in it, and those people have done the most since the beginning of the i550 to promote the i550.

About my boat's odd stuff: I've been very open from the beginning about the stuff I wanted to do, and asked repeatedly both when Watershed and the designer were the rules authority and during the time that other rules were being drafted, "what can we develop, what needs to stay per plan?" The answer from both sources was that the hull shape needs to be per the plans, and the other bits were open. Nobody wants to (re)build new hulls to be competitive, but most folks that are handy enough to build a hull are able to do any of the developments I've tried. If at some future point the class decides that something I've done is bad for the class, then I'll have to live with that- my rig and keel can be locked on center, for instance. But I would hope that the test remains "what is good for the class?"

I can't defend the round deck and inboard rudder decisions- I think the round decks are fine, and the inboard rudders are just a heavy waste of time. I can see "preservation of the brand image" as an argument a few years ago, but I think that horse is out of the barn today.
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Re: Forestay attachment point

Postby Tim Ford » Mon May 21, 2012 2:56 pm

I'm not even sure we have "leadership" at this point, but that's OK. And I am in agreement that there's too much bad blood over the dam, to mix a metaphor.

This is not to prolong or start up a dormant debate, but with a lot of new people signing up for this Forum, a little history may be in order. I do not think this thread is the place for it, though. I do think that we probably got a tremendous amount of bad ink on the i550.org site. We elected not to engage.

One myth I would like to put an end to, though: There is a lot of talk about how so-and-so mods will not really effect performance of one boat over another. This is basically Joe's chorus over and over again on the SA thread. I can say with absolute certainty, that: yes, the mods will. Anyone who has done a modicum of OD racing in a strict OD class will verify this.

I bought into a class that had the potential to see winning boats at the podium due to racing skills. In the middle of my build, it morphed into a class where races are won in the design, shop. That's OK, and I understand the appeal of that. It's just not the kind of racing I prefer and I suspect the "open" class will need to introduce ratings and a handicap element, eventually.

In a world of home-built boats, that's the reality of the situation. And frankly, while a little disappointed, I have come to grips with it.

----- edit: I started a brief history thread and apologize for the hijack here in ryderp's thread ----------
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Re: Forestay attachment point

Postby Kevin » Mon May 21, 2012 4:58 pm

My closing thought on the high jack is...
This boat is supposed to be about fun. Anything that makes this un-fun will drive people away. We've taken basically a year off from any kind of class activity for many reasons. We published the rules in April 2011. If people are interested in doing class based events, then discussions about those events and the rules they will follow should be done in other threads. I frankly am trying to just get my boat on the water again and go sailing. That's my 2012 goal.

Kevin.
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Re: Forestay attachment point

Postby Chad » Fri May 25, 2012 6:00 pm

ryderp wrote:Also, there was a previous post on sail area, but what are the luff and foot lengths?
Phil

Here's what I come up with- based on 2 degree mast rake for the forestay/luff length in both cases, and based on Jeff's PH cert for LP, and pics of the Jeff, Kevin, and Ron's sails for their rough foot geometry; and based on the dimensions I gave my sailmaker for the jib I'm buying:

i550_jibs.pdf


(Jon, I drew the shape described by your numbers, but the 250" leech puts the clew below the deck somewhere, and I'm not sure if by J you meant the foot dimension of the sail, or just "J").
You do not have the required permissions to view the files attached to this post.
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Re: Forestay attachment point

Postby jray » Fri May 25, 2012 6:12 pm

I will get the jib out tonight and get some actual measurements.
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Re: Forestay attachment point

Postby jray » Sat May 26, 2012 2:55 am

Actual measurements are 244" luff, 224" leach and 85" j. I got screw up by posting the other measurements off of a email with my sailmaker and assumed they were what we made the jib to. Sorry for the misinformation on the first post. :?

Good catch Chad!
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