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-   -   North sails mast compatibility (http://www.star-board-windsurfing.com/forum/showthread.php?t=2287)

Guest 20th July 2007 12:35 AM

North sails mast compatibility
 
Tried to rig my North Natural 6.6 (2007) on both Arrows and Simmer masts (haven't tried the North).
When downhauled to max specs, and no boom attached, the batten above the boom protrudes in front of the mast (2-3cms). I need a significant amount of outhaul both in distance (4-8 cms) and in force, to pull this batten to the side or behind the mast and to get to the min outhaul specification.
Is this normal or could this be a mast incompatibility issue?

Thanks.

Roger 20th July 2007 10:44 AM

RE: North sails mast compatibility
 
Hi guest,
It dpends on how you apply the specificiations?
I checked the North Sails 2007 specs, and the 6.6 m2 Natrual does not have an adjustable head strap
The mast needs to be a 460 cm IMCS 24-26 extended out to 474 cm (that's 14 cm of additional mast base extension.
Then you need to check your mast base against a North extension to see if your pulley sheaves are the same distance from the mast collar on the base.
All of these things could add up to you needing to put to collar 1 or 2 holes higher on the mast base to get the correct tension and get enough downhaul to pull the batten above the boom back to at least the middle of the mast.
4-8 cm seems tike way too much outhaul, but you need to check the VTS (Visual Trim System ) to see if you are getting enough downahul.
If the scallop in the uppeer panel of the sail is not extending in from the leech to the VTS dots, then you definitely need more downhaul and the only way to do that is to extend your mast until it's long wnough so you can bend the mast, completely with downhaul until the leech loosens to the Trim Dots.
Then use the outhaul recomendations that are printed on the sail out by the clew.
So, in summary, you coulld have a compatability issue, especially since the sail is designed on the North "2 mast" system.
Hope this helps.

Guest 20th July 2007 01:58 PM

RE: North sails mast compatibility
 
I use North extension set to 14 cms and downhaul until the pulleys meet.

Using 18 cms of extension:
http://img223.imageshack.us/my.php?image=cimg2442ac4.jpg

, I can derotate the batten to a reasonable position with downhaul only (aligned with the front of the mast), but the leech just looks ridiculous with this much downhaul:

http://img517.imageshack.us/my.php?image=cimg2436fq5.jpg
http://img183.imageshack.us/my.php?image=cimg2437rk0.jpg
http://img101.imageshack.us/my.php?image=cimg2438eu6.jpg
http://img216.imageshack.us/my.php?image=cimg2439ky3.jpg
http://img180.imageshack.us/my.php?image=cimg2440xw0.jpg

WSguy 20th July 2007 05:50 PM

RE: North sails mast compatibility
 
Either bring the sail back or buy a North mast. A Gun Terminator mast will work with North sails, too.

Roger 20th July 2007 05:51 PM

RE: North sails mast compatibility
 
Hi Guest,
Next time take your pictures from the foot or tack of the sail, with the mast base pressed down to the ground so we can see the tuning marks.
It almost looks like you are well past the max. downhaul in the last photo (img180) but it's very difficult to tell.
I would say don't be afraid to loosen the leech, but I agree your photos show a sail twisted on to the extreme.
Can you just downahul a bit less at the same mast length and not get the foot quite so low? Maybe somewhere between 14 and 18 cms of extension will get the scallop in the top panel in to the tuning marks, and not beyond them.
Only other thing you can do is to borrow/purchase the correct North mast and see if it's rigs your sail any differently.
Hope this helps,

AlexWind 20th July 2007 06:14 PM

RE: North sails mast compatibility
 
From the images it seams you've put a bit too much of downhaul..

Second, the mast you have may be wrong: not every costant curve mast has the same curvature..

Guest 20th July 2007 06:54 PM

RE: North sails mast compatibility
 
I will try to play with tuning some more, but I strongly suspect it's a mast (curve) incompatibility issue (looks like sail needs less flex top and more flex bottom). I will also try to get my hands on a North mast and post my findings here.

Thanks.

Guest 20th July 2007 09:40 PM

RE: North sails mast compatibility
 
I agree with Wsguy. Rig the sail on North mast. On photos wrong mast curvature ir seen very clear. Used mast has too soft top.

Dont use that mast. You'll have rotation problems and flutter will destroy monofilm upper panels.

Also North camberless sails usually has very nice and smooth entry. In this case sail looks terrible.

Guest 21st July 2007 03:10 AM

RE: North sails mast compatibility
 
Note that pictures are with sail downhauled 2-3 cms beyond max spec and that's what's causing loose leech. I definitely wouldn't go sailing rigged like that, this is just to show that excessive downhaul is needed to de-rotate the batten above the boom.
With less downhaul but again to max recommended spec (474), the leech looks good and top panel looseness meets max VTS marking, but then the batten sticks in front of the mast:

http://img516.imageshack.us/my.php?image=cimg2444mw8.jpg

needing massive outhaul to correct.

It would be most helpful If any owner of a recent camless North sail could compare where batten tip ends when downhauled and no outhaul tension?

Thanks.

Guest 21st July 2007 05:41 PM

RE: North sails mast compatibility
 
The problem is OBVIOUS. No need for further replies. Your mast is clearly not correct. As you very well know!


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