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bred2shred
Joined: 02 May 2000 Posts: 989 Location: Jersey Shore
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Posted: Fri Dec 08, 2017 7:04 pm Post subject: |
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skyking1231 wrote: | i maybe getting a 7.8 sailworks NX...which unfortunatele...says it needs a 29cm extension. was hoping my 28cm would work....i guess i'll have to see...and if not get the bigger one. (unless someone knows already the answer ???? ) |
If it’s only off by 1cm, you could probably rig up some sort of mini-tip extension (I’m sure some will flame me for suggesting such a thing). Depending on the type of head fitting on your sail, this could be a very simple solution. I added about an inch to a mast many years ago by making a custom wooden plug which I glassed into the tip of the mast. It worked fine for my needs and held up with no problems.
The other option would be to use an “extendo,” but that probably won’t save you much compared to just biting the bullet and buying a tall extension.
sm |
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gregnw44
Joined: 23 Jul 2008 Posts: 783 Location: Seattle, Wa
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Posted: Sun Dec 10, 2017 4:51 am Post subject: |
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Skyking - "I would not worry about THIS at all" !!!
That's a cool sail... the luff length is 488cm... you have a 460 mast, I'm sure that you'll only need 28cm of extension. Yes, I see the chart that says, you can use 29cm of ext.
But I have lots of Sailworks sails... and I'm quite sure you can get away with 28cm of ext, haha!
Exception - If you look like... and are as skilled as... and sail as over-powered as Bruce P and Dale C... and you want to get the fastest top speed, in very high wind like those two... then yes, it would be nice to get as much as 29cm of ext on that 7.8 Nx.
However, if you are NOT going to sail quite like those guys, then I'm quite sure you will be fine with 28 cm of ext
Personally, I often rig my Sailworks race sails with 1 to 4 cm less ext than they suggest. And my sails still rotate easily... cams stay on... sails are smooth with no wrinkles... top still twists... they are fast, powerful, and controllable.
What I'm saying is, no need to worry about 1cm with that sail, in my opinion. And if you don't believe me, that's fine. Borrow a friend's longer extension and accurately rig and compare all aspects of the sails performance... with 28 cm ext and with 29cm ext. I'm saying, you "might" notice the difference if you're a total expert and racing slalom with a NX 7.8 in 25-30 mph wind. But if you're doing something less than that, I'm sure you'll be fine with 28cm ext. Anyway, if you buy that sail and I'm wrong (no guarantee from me, just my opinion)... you can always buy a longer ext later (but I doubt you'll need to).
PS - And, if you decide later that you "really" need 1 cm more ext.. I have lightly used longer ext from Chinook, Epic Gear, and others... I'll sell you for less than new.
Or, put a thicker mast tip plug, in the top of the mast (that what you have now). As was suggested, you "might" pick up 1/2 cm of thickness there. Just make sure your mast tip plug fits the male "pin" at the top of the Nx. _________________ Greg
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skyking1231
Joined: 10 Jul 2000 Posts: 280
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Posted: Sun Dec 10, 2017 9:11 am Post subject: |
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thanks greg....
did you have to put shims in the cams ? on the nx |
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U2U2U2
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Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Sun Dec 10, 2017 10:10 am Post subject: |
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Those north lever extensions have been in service for some time. I never saw a need for them.
Reference your 28 cm extension. Vs the 29, I disagree with the posts the 28 will do. Your mast is probably not what they used, and enough factors present themself that extra on top of what’s recommended is adviseable.
Since a particular sail now enters this, I would look at other options, on a sail, that may not require that length of EXT.
Having said that, length EXT bit, , I feel you will find, 7.5 size is less, and your 7.8 proposed , will require the long extension.
My self I would be more concerned with the boom length than mast/ extension. Due to short arms.
This a recent ongoing take on some of the same issue.
http://forums.boards.co.uk/showthread.php/78620-Mast-extension-maximum-and-minimum-safe-overlap _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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gregnw44
Joined: 23 Jul 2008 Posts: 783 Location: Seattle, Wa
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Posted: Sun Dec 10, 2017 12:21 pm Post subject: |
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skyking1231 wrote: | thanks greg....
did you have to put shims in the cams ? on the nx |
I have several Sailworks (and also other race sails) and they're all different regarding needing shims or not, which is normal. The shims that most use these days work great, and they're easy to figure out, and to deal with.
For Nx's - first rig without shims. You want the cams to rotate with a nice pop, it should take a little effort, but not be too much work. This is EASY to show at the beach, less easy to write about.
Anyway Bruce tells people, there should be a little vertical wrinkle in the luff sleeve around the general area of the cam. Again this is easy to show at the beach, tougher to explain via words. But if the luff sleeve is too baggy and loose, than add a shim. Play with this, and try the 3 different shim sizes, until you get it the way you want. I like mine to rotate easier than some, and I don't mind a bigger wrinkle (or 2 small ones). Other hard core expert racers (which I'm not) like the sail and the cams stiffer, and they want the luff sleeve tighter... so they add a bit more shim. A caution is - if you add too much shim, you won't be able to rotate the sail at all (unless you're Dale C and in 35 mph wind). _________________ Greg
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gregnw44
Joined: 23 Jul 2008 Posts: 783 Location: Seattle, Wa
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Posted: Sun Dec 10, 2017 1:10 pm Post subject: |
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Other thoughts regarding luff length and rigging -
Most all sail designers (including Bruce at Sailworks) say to use the printed sail luff lengths and boom lengths, as a guide... a starting place.
They are not meant to be an absolute directive, never to be wavered from
Yes, for people that don't have any idea what a good sail looks like (not the experienced people on iW) the printed specs are a great default... and using them (with the right mast and boom) will probably be pretty darn good.
And I agree that it's always nice to have a little extra to play with... cause you might want a little more or less than the specs.
Also... many sails give a range of luff length or boom length. Some might say to always stay within that range... but again, I've had reasons to rig just under or over that range on sails... and I always get the results I want (and I like sails that are easy to sail with... and easy to rig).
Also as was said, all 460 (or whatever size) masts or not exactly 460cm's. I measure em whenever I get new or used masts, and I have lots of them. Your 460 could be a slight bit longer or shorter than the 460 Bruce used, even if it's the same brand and model (brands will change the tip plugs sometimes)... this is not exact, to the precise mm.
Back to luff length for a Nx 7.8... they're suggesting 488 or 489 cm. Which is 16' and 1/8" to 16' and 1/2". Do you think you're going to notice the difference between that... while you're flying across chop, trying to maintain balance, hanging from your harness, feet in the straps, weight shifting from foot to foot, heal to toes... left hand to right hand, sheeting in and out... top of the sail twisting back and forth every time you hit a new piece of chop?
Cause there's no way I'd notice it... I just have a big grin on my face... and I'm not thinking about if I have 16' and 1/8" downhaul... or 16' and 1/2" of downhaul. I'm just trying to stay in control and keep everything trimmed right... and I'm thinking about what I need to do to carve through my upcoming jibe, haha!
Yes, if the sail is rigged poorly... sails like crap... or doesn't rotate... yes, I will notice that. But it won't be from varying the total downhaul a cm or 2 from the precise spec.
Like I said before, there are times when I reduce the downhaul several cm's from spec... and it's cause I'm underpowered, and want more power from the sail to get planing. Reducing the downhaul will make a fuller sail and reduce the twist at the top, which will help give me some more power that I want (if the wind is lighter).
But I never under downhaul a sail to the point that I can't control it easily, or the cams pop off, wrinkles, poor rotation, etc.
You should experiment with how much downhaul you want... and it might change a bit. for different conditions. You will only know what you like and what you can make work, after lots of sailing, practicing an experimenting. _________________ Greg
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coachg
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Joined: 10 Sep 2000 Posts: 3550
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Posted: Sun Dec 10, 2017 1:33 pm Post subject: North System |
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skyking1231 wrote: | a little off topic.....has anyone tried/used the Noth extensions with the built in lever winch ? I have my concerns about it....seems like taking something simple...and making it too complex....if you needed the 'pull'...a rig winch works fine. anyway.... |
We have been using them for a couple of years now with no problems. It is a loop and go system so far faster & easier rigging than the standard system. Adjusting downhaul on the water is amazing. Takes longer to release rig tension because you ratchet down instead of pull & pop like standard. Like everything else it is personal choice. It is a major time saver for us because we have to rig multiple sails for teaching. An individual rigging just one sail, maybe not so much.
Coachg |
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U2U2U2
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Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Sun Dec 10, 2017 2:22 pm Post subject: |
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Gregnw44
Wrote..
They are not meant to be an absolute directive, never to be wavered from Smile
Yes. So 2 cm either way , is a reasonable deviation. Hence the 1cm to short EXT caould be 3cm short. _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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U2U2U2
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Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Sun Dec 10, 2017 2:23 pm Post subject: Re: North System |
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coachg wrote: | skyking1231 wrote: | a little off topic.....has anyone tried/used the Noth extensions with the built in lever winch ? I have my concerns about it....seems like taking something simple...and making it too complex....if you needed the 'pull'...a rig winch works fine. anyway.... |
We have been using them for a couple of years now with no problems. It is a loop and go system so far faster & easier rigging than the standard system. Adjusting downhaul on the water is amazing. Takes longer to release rig tension because you ratchet down instead of pull & pop like standard. Like everything else it is personal choice. It is a major time saver for us because we have to rig multiple sails for teaching. An individual rigging just one sail, maybe not so much.
Coachg |
This may deserve a thread of its own. Good info may be missed. _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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skyking1231
Joined: 10 Jul 2000 Posts: 280
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Posted: Fri Jan 19, 2018 12:59 pm Post subject: |
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I rigged a sailworks 7.8 NX (which requires 29cm)...with the chinook med at 28cm.
I am able to get the med downhaul setting no problem. And pretty close to max setting. About a cm or two beyond the downhaul reference mark (cog symbol). Although i think it would work fine for me....i am a bit concerned about the amount of tension....and the load on the extension itself. If i did try and modify the exension longer....i think it would fail after a session or two. I may get a slightly longer one ....keep the 28cm as a backup. |
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