MERLIN ROCKET FORUM

Topic : Job sheet angle to forestay

Hum quick question on this
 
I know roughly in a normal breeze the jib sheet should go at an angle that roughly  go to half way up the jib
 
Also know that if top tell tales are  lifting first  you need to move cars forward or in my case drop the poles down  that hold the jib sheets ( I think )
 
But  when we start raking the angle of the jib sheet goes much lower that half way  
 
Normally in windier condition s people move their  jib cars forward or again in my case the poles down
 
Question is do we do this to maintain the 50 % angle rule or is it we generally want  more jib leech tension 
 
 Sorry bit technical for the morning 
 


Posted: 19/11/2019 09:00:49
By:
In terms of the jib sheeting angle to the forestay I generally leave this the same for all conditions, just adjusting the tension to keep the shape correct.  The way that I look at it is you can use tighter leech tension in the lighter winds, but as the wind picks up and you start to rake then there is enough wind to start switching modes from pointing to speed and more twist in the sails allows for this. Also as you are more likely to be easing the main as well this helps maintain a good slot, rather than choking the slot, as you are not playing the jib just the main.
 
The distance between the sheeting point in the boat and the jib clew will affect the rate that the angle changes, as the traditional jib car track is further away from the jib it affects the angle less than one closer to the jib, which yours is, so it could be that you need to tweak the position slightly when getting to the more extreme rake settings.


Posted: 19/11/2019 10:30:41
By: Stuart Bates
Hum was thinking the jib is like the main. Less leech tension in lighter stuff
 
Also was thinking easing the main closes the slot  ??   The great gning with the poles holding the jib sheets you can set them really wide
 
My problem I think is that my poles are set on a bracket really far forward  whereas notice the later ships had their poles set further back
 
The boys at the Welsh harp boat centre have fitted extension on the poles which makes them higher ( almost 4 inches  to achieve the 50% rule  )how that goes   
 
Agreed need to work more on transition to speed particularly in waves  


Posted: 19/11/2019 17:12:40
By: Logan
I have debated this all season with various mates in the class and out. 

Colin has a great point about our board position and we have definitely found that being able to sheet at a wider angle helps massively. 

Stuart is also right that sheet tension is a huge factor and being able to graduate/calibrate sheet length is important.

Over the winter I am fitting the same X/Y car system Simon Potts has in his new boat that was at the dinghy show.

A floating eye system. This will give us a large range of options.

Jon Turner also suggested yesterday that extra leech tell tales help on the jib. 


Posted: 20/11/2019 13:28:29
By: Gareth Griffiths
Apologies for typos..!

OUT board sheeting


Posted: 20/11/2019 13:38:16
By: Gareth Griffiths NHRC
I've only one tell tale right at the top of the jib 
 
You would think it would be more like half way up
 
Still not sure my question at the top  


Posted: 20/11/2019 15:29:52
By: Logan
I think yours is the same as mine and is about 4/5ths up from the clew

Maybe one about half way is what JT was saying.


Posted: 20/11/2019 17:03:51
By: Gareth Griffiths NHRC
Yup will go for that. Literally mine is a foot from top


Posted: 20/11/2019 17:23:53
By: Logan
I put longer bars on mine around this time last year.
 
Then after much faffing around I had a look at it - Wembley open I think - and pulled the poles down. A lot. We came 4th I think. I have marked it and left it pretty much alone since.
 
I think this base setting is rather higher than 50%. Before I must have been enormously too high, but it did stop the crew from oversheeting. 
 
Only caveat to this is I have the larger jib.


Posted: 20/11/2019 17:53:50
By: Chris Martin
What’s the latest thoughts on the jib tack point up north? 

(North of Lyndhurst)


Posted: 20/11/2019 17:59:17
By: Gareth Griffiths NHRC
I like my arrangement.
 
If I was having another boat I'd do the same again. 


Posted: 20/11/2019 18:17:57
By: Chris Martin
What set up have you got Chris?
 
Longer Jib Bars and a Stem mounted forestay?
 
What sizer is your Jib? 


Posted: 21/11/2019 10:52:06
By: Gareth Griffiths NHRC
Chris
How high is your jib block now above the fulcrum Jib Bar bolt? I have standard Winder bars on 3785.


Posted: 21/11/2019 12:25:33
By: Robin Charles
They are 100mm longer. I now use the bottom of the range rather than the top as I did with the original bars.
 
But I have the large jib so might have different requirements. If I was doing this again I don't think I'd bother with the bars. 


Posted: 21/11/2019 14:16:49
By: Chris Martin
Geoff O'Neil has put a temporary set  up that puts the block an amazing 6 inches above where it was before 
 
Sailing this weekend   bit of a dodgy southerly but  will be interested to see
 
Still thinking the tension on the leech of the jib and the foot should be equal  
 
As I said before my bar that holds the jib pole  is well forward on the centrecase and I reckon the newer boats have them set back aft  
 
 


Posted: 21/11/2019 16:41:53
By: Logan
They are slightly further back on the later boats.
 
Longer bars do the same job, but you do have to watch for bend! If you plot onto the floor of the boat the amount of adjustment you get on the bars 10mm height is tiny. I think the whole range only covers 5 holes on the old tracks. So you can afford to move the bars a lot for a given adjustment.
 
I haven't got the chisel out yet, but I think I prefer the tracks. 
  


Posted: 21/11/2019 17:52:15
By: Chris Martin
Sorry Gareth, I missed your post.
 
I'm using a Winderised Genii rig, 3.12 jib and 2393 mainsail foot. Bow tacked with adjustment bars.
 


Posted: 22/11/2019 08:33:29
By: Chris Martin
Cheers Chris...


Posted: 22/11/2019 09:25:47
By: Gareth Griffiths NHRC
In the early 1980,s transverse tracks with floating block height adjustment became the norm on grand prix offshore 
yachts, by 1990 they had become extinct.
Jib Cunningham and forestay tension (correct jib luff round for conditions) combined with a control line adjustable fore aft jib track with known base settings dependant upon mast rake is simpler to quickly adjust for changing conditions. An in hauler for light airs flat water is a useful addition, only a very small amount of available adjustment 
adjustment, very easy to stall slot in these conditions
 
Colin Simmonds
3478 


Posted: 24/11/2019 12:18:52
By: Colin Simmonds
Probably need to get my head out of the boat ease the jib sheets and get going 


Posted: 24/11/2019 15:29:01
By: Logan

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