|I mentioned earlier in another thread that I have been having difficulties finding the best possible trim for my Y2000 North IQ Race 5.8.|
The sail either rigs with not enough twist or with not enough shape down below the boom. There's a compromise setting in between, but it's a question of millimeters of downhaul to find it.
As suggested, it does seem like it's a mast compatibility issue. Apparently the Excellerator 60 mast that I have is either slightly too stiff in the top or too soft in the bottom. Most people probably wouldn't see the problem, but I'm pretty sure it's there...
I tried a Viper 75 on Wednesday and four other masts today (two of those were Viper 75s too, but different production years, so I wanted to see if there were any differences).
The curious thing is that _visually_ the best fit so far is with an old one-piece Fiberspar World Cup Carbon 440/Purple. I have no idea how stiff that mast is, but it's a combination curve (slightly softer top). I used to love that mast with the 5.5 Prisma (ca 1995 vintage), but the guy who bought the Prisma refused to buy the mast because it's not a two piece mast (I can understand that, but it really was a perfect fit).
I also tried a Sting-30 and the sail looked very similar to what it looks like with the Vipers, but the Sting is just too heavy to use with a sail that is already a bit too much on the heavy side (for waterstarts etc).
I suspect that even though the Fiberspar looks good rigged, it may be too stiff. I'm trying to sell the XC60 and buy a used Viper 75 (I can't afford a 100% mast right now).
Any thoughts on the Purple curve Fiberspar & North IQ? I couldn't find the stiffness specifications online.
Part of me is wondering if I should just get a new sail...
Personally i do not use these North IQ's, but i do have the 8.2m IQ. (never used it)
Anyway what I have seen is most likely the only work around.
1/ Use excessive downhaul, more than recommended.
2/ A little negative outhaul.
3/ Crank the bottom mast tack strap until the bottom looks all deformed & ugly.
You then likely will have a fast responsive sail?
Hope that helps.
|Juri... backing up what michael commented.... back when I actually owned a 5.8 North .. the same model as yours I treated it the same as both the 5.4 and 4.6 regardless of wind condition ... that was .. maximum to overdownhaul ... at least 20 to 30 mm negative outhaul and pull the tack strap to death |
as noted by michael .... it looks pretty rough but it works .. I rigged the 5.8 that way with both the xcellerator 100% and also the north 60 % carbon mast ..
This technique should resolve both the feeling that the mast tip is too stiff and the lower mast is too soft... the overdownhaul will guarantee twist off at the head and you can then simply control the fullness of the sail with the tack strap .... rather than the outhaul
good luck with the quest! Chris
|I've been doing the downhaul & outhaul as suggested, but I haven't been putting all that much tack strap tension. I find that the tack strap just "rides up" if it's really tight, but maybe it's because the Pro-Limit (Autima) extension doesn't have a really good notch to hold the strap in place. I have already modified the extension a bit and will attempt to make it better.|
I'll probably have enough wind to do some testing later next week.
The biggest problem I have had with the sail overdownhauled is that it goes upwind really badly. Using it on a Hypersonic sort of hides that problem, but narrower boards really suffer.
Even as it is on the XC60 mast, it is clearly my fastest sail when I get it tuned right. I think adding a bit more drive down low will only make it better, but I guess the GPS will tell if that's so.
|Juri .. even the base system you use could make a difference... some bases have pulleys that stand out up to 20 or 30 mm from the mast... and combined with a badly trimmed sail that is to high above the pulley... it can be harder to pull the tack strap in hard .. whereas a base pulley that is closer to the mast does a lot of the work in positioning the tack for you..... |
just another thought
Athough all my sails are North, I'v not used or owned an IQ. What I can tell you and it might help, is that on an old video tape I'v got (Northsails Speed IQ) Mica Buzzi rigs up a 6.5m IQ 3 plus and he puts loads of tension on the tack strap, and as Michael Howard says, the forward bottom panel gets really creased, deformed and ugly. In the video, the sail looks full at the bottom and twists off nicely at the top. Maybe get hold of a copy and have a look. If you cant get hold of a copy, I'll see if I can take a DVD copy off mine and post it to you.
|I used to have a 6.8 IQ+3. Nice sail, but the Warp III is clearly better. I guess one of the big improvements in the Warp III was exactly the amount of shape below the boom without any compromise in high end handling.|
The IQ Race is quite different from the IQ+3. IQ+3 has one camber below the boom and three above, whereas the IQ Race has two below and two above.
I'll try some other extensions. I remember being pretty happy with an North extension (it has a proper notch for the tack strap, but otherwise it's not that different from the Pro-Limits).
I still think it's a mast issue and it might be just that one mast that is slightly out of spec instead of all XC60 masts.
Would it be worth trying to mix up the masts, IE softer top half and stiffer bottom half. I'v heard of some guy's doing this with nitro's to gain better bottom-end. Dont know, but might be worth a try.
|I sailed the 5.8 with a Viper 75 on Wednesday. The conditions were probably not ideal, but it was a definite improvement.|
I bought another Viper 75 today and used it for about three hours. When I rigged, I was pleased to see that of the four different Viper 75s, this one looked the best.
I started with relatively low downhaul & outhaul and the sail was working perfectly well and twisting off in the gusts without problems.
Going to the other extreme made the sail lighter in the hands, but I went a bit overboard given the variable conditions. Even with the extreme downhaul, there was still some shape low down in the sail and the cambers were not derotating.
I haven't tried the Fiberspar yet. I'm kind of wondering if I should try it some time just out of academic curiosity. It rigs just a bit deeper low down than the mast I bought today. It's an old mast, so I doubt its reflex response will be as good as the Viper's.
I used the same Pro-limit extension as before. I applied lots of tack strap tension at first, but I felt it made the sail favor one side over the other (flat/full), so I left it relatively neutral. I guess the mast bend was providing enough shape low down, so I didn't need it.
Somehow I forgot to turn on the track logging on my GPS, so I didn't get any log data. Not a huge loss though: I think I could have used even more wind the few times I tried going deep downwind. Sail & board (Prokids S-Type) control were never a problem.