Tuning Issues

[jeremyf]

I have now started to re assemble Grimalkin and am thinking about issues like mast heel position / jib sheet angle etc etc.
I have read the 'tuning guide' with interest and will use that as my bible but can anyone start me off with some 'proven' settings for a Cheshire Cat ?
In particular :-
Mast heel position say measured from inside transom
Spreader height above s/l, width and depth.
Rake
jib fairlead position from centre line and transom or bulkhead
 
I hope a reasonable start point may avoid 'gruyere cheese' syndrome at a later date !

[Antony (Guest)]

Jeremy,
The core tuning guide that almost all people start with is the article by Dave Peacock (even though it was for his Bagggy), perhaps with the added benefit of the P&B Design 8 'numbers'.  Where these are applicable i suggest that you use them as a starting point as you will not be too far wrong.
Antony

[jeremyf]

Thanks for that.
Sounds sensible.
jeremy

[Derek]

Jeremy / ANthony,
 
Just one comment about Dave's numbers.
Baggy, in a particular Dave's and Rob's were built with a very short shroud base to allow the boom to swing further with the rig tension still on. If you take a line from the back of the mast to a line between the shroud points, this was just 10" for these boats. They were such a step in speed that most subsequent boats had a fairly short shroud base as a consequence. Earlier boats, like the Cat will have had 12 - 14" as a shroud base and so the spreader dimensions in particular will need a bit of adjustment to reflect this. As a suggestion for a starting point, put he mast in the boat without the spreaders connected and set the rake and tension as desired. Then mark up the spreaders to give you perhaps 1½" outward and ½" forward deflection of the shroud. I seem to remeber these numbers being about right for a proctor "C" or a Kappa. Then put it on the water in fully powered up conditions and see how the boat points and how it bends and make adjustments from there. I am sure someone else will offer updated advice if I am wildly wrong.
Good luck
 
Derek
 

[jeremyf]

Thanks for that Derek, I will give that a try.
Jeremy