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12th October 2013, 02:28 PM #1
- Join Date
- Oct 2013
Looking for some advices to apply correct downhaul on a tushi raptor c2 7.2
I recently purchased a Tushingham Raptor C2 7.2 (twin cam) and i'm looking for some advices for applying the correct downhaul on it.
I use it with a Tushingham 45 460 mast.
It's quite an old sail and I haven't been able to find any manufacturer information about it.
I sailed it 2 times at Queen Mary reservoir, applying as much downhaul as possible but i'm not sure what that should be. It seemed to behave fine except that i felt the center of effort what shifting quite a lot depending on the gusts but then quite stable while planning. Also I found it quite hard to go upwind compared to some other sails like Gaastra Matrix I used before, but that could just be my technique or just the board/fin i'm using. Since it has cams, the only clue i'm using to have an idea of the correct tension is to look at up to where the leech becomes floppy. The photo below shows what settings i'm using at the moment.
I just bought my own kit and ti's the first time I setup the equipment myself.
Does someone that used the same sail or a similar one can give me some rigging advices ?
12th October 2013, 02:44 PM #2
Difficult to see settings on that picture (from this phone).
The principles of downhaul however are: too little downhaul means the sail can cause catapults. Too much downhaul means the sail feels gutless and gets you planing later and doesn't go upwind well.
So best bet is to try different settings, with the leech floppy to the first batten as a minimum setting.
As you add more downhaul the leech should set more floppy but if you overdo it then you effectively sheet out the top of the sail meaning less power.
Every time you adjust downhaul you should also check the outhaul tension. If the sail feels like it has a moveable centre of effort then this often a sign of not enough outhaul.
I'll others add to this - and hopefully you will get comments from someone who has used the sail in question.
Last edited by basher; 12th October 2013 at 02:48 PM.This space is kept clear for random notes, reminders, or a shopping list.
12th October 2013, 05:48 PM #3
I use more modern X15's but the principle is the same. Where you have your red line, I would move that up to the batten above and that would be maximum of the floppy leach, then the batten above that minimum floppy leach, with options in between, which would probably be no more that 2cm on the downhaul between the two points.2015 Sessions: Speed/Slalom 10, B&J/Wave 09, SUP/WindSUP 04
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12th October 2013, 08:05 PM #4
- Join Date
- Oct 2013
Thank you both, I will play with this range next time. I read a lot about downhaul and outhaul settings the last days, I just wasn't sure how far I should go.
By the way, what are the major differences between a modern x15 and my old raptor ? If you compare two identical size. Would it worth investing in some more recent sails ? let say a 7.5 and 6m2, 4 to 5 years old ? I'm quite a beginner i windsurf since 3 years, planning in straps and trying to nail the planning exit on my gybes.
12th October 2013, 08:53 PM #5
- Join Date
- Nov 2009
The modern equivalent of the Raptor is the Lightning ( 2 cams) rather than the X15 ( 4 cams). You have already been given good advice I reckon, and the fact you recognise/feel what the sail is doing is a good first step towards getting it set right. The raptor like the Lightning is a relatively low tension, soft rotating twin cam....meaning it is really quite close to a 6/7 rotational sail but with extra support for the profile provided by the 2 cams. This means it needs both the right amount of downhaul and positive outhaul tension to give a good set. This is especially the case in larger sizes like yours where the twin cam set up is going to have a harder time controlling the total sail area. Your max downhaul is when the panels with small leech battens are loose. Your outhaul is best set with about 1/2 cm positive, that is 1or 2 cms from a neutral position. A neutral position is the amount of tension you can apply to the outhaul using just one finger and a thumb ( not a lot!). In terms of your observations, provided you have not over-downhauled, the centre of effort moving about is probably due to insufficient outhaul. The same would be the case in terms of upwind ability......... a flatter profile ( within reason) is faster and cuts upwind better....but may be a little slower to get going and have less bottom end grunt.
You could also check the amount of tension each of the cams has, and use spacers/batten tension if required to increase that tension. Best guide is, with the sail rigged, try to rotate one cam with one hand.....it should just be possible. If it is easy and/or the cam is floating away from the mast, you need to adjust the cam tension ( not sure on the raptor whether that is done via the batten or with spacers to be honest).
12th October 2013, 10:53 PM #6
- Join Date
- Oct 2013
woo thanks... very useful info
I think my outhaul was about correct, sail barely touching the boom when pushing on it with the arm, and as I remember it was near what you described.
On my first day sailing with it, it was much less windy and I didn't put so much downhaul, and somehow I remember I found it very easy to pop in the plane in gusts, without any effort. It was the first day trying my xcite ride 122 too and I remember telling to myself that the board was incredibly easy to get planning. But there wasn't much wind and I didn't plane much.
Last thursday, it was more windy and I applied a lot of downhaul to try. And actually I may have over done it. I remember noticing some creases appearing on the panel next to the boom and I thought it might be too much but still went on with it. Thinking about it I think I actually applied way too much downhaul and this must have been a very bad setup.
Can you elaborate on the effect of over downhauling a sail ? My way of thinking about it was that I may loose some stability but would lower the center of effort so have a more comfortable ride in the wind which was too high for the sail, i think the others were using 6 or 5.3 sails this day. I remember struggling the whole day adjusting my lines trying to find a neutral position for them. And the stabilities issues i described before and poor upwind ability.
12th October 2013, 11:08 PM #7
What downhaul does is to bend the mast. That pulls 'luff round' and fullness out of the sail – because the mast bend curve increases with more downhaul.
The sail then flattens and the head twists open more.
That sail twist can release power by sheeting out the upper part of the sail.
With more mast bend, the outhaul slackens too.
With increased downhaul, the opening head should indeed mean the sail drive is lower – but you only want that if overpowered.
If others were on much smaller sails – then maybe you were on too big a sail too. Then again, cam'd sails generally have a greater stability and better top end.
It's also worth mentioning that a gusty wind day, on a lake, is no time to judge a sail with apparently variable power delivery.
The slack outhaul can mean the lower panels have less tension, allowing the centre of pull to move around in gusts. Sailing downwind, you probably won't notice this. Sailing upwind you might.
Sailing upwind, is generally better with a good bit of positive outhaul. (Pull the clew to the boom end and then add some.)
You also mention poor upwind performance. To be honest, in windsurfing that is usually down to experience and practice, more than it's about sail setting.
Last edited by basher; 12th October 2013 at 11:17 PM.This space is kept clear for random notes, reminders, or a shopping list.