spreader height

[tonyelgar]

I am currently replacing my mast and have the old mast with the spreader height quite high and the (second hand!) replacement donated from a lark having the spreaders much lower. Is there an optimum height people are going for? I'm guessing with the spreaders lower down the  lower - middle of the mast will be stiffer?
 
cheers
 
Tony

[johnk]

It is possible to move the spreaders up or down the mast. Just fill the old screw holes with araldite or similar to reduce water ingress after a capsize. Obviously the spreader length may then need to be altered. 'O' level geometry comes in useful here.

[Measure twice (Guest)]

Roughly 12-18 inches higher than the lark rig as I recall.  At least that’s where the rig that accidentally had the spreaders put on in the lark position had the holes.  The tuning guides on the site probably have something about it.  If not any of the main sailmakers will provide you with good info.
 
Putting the spreaders too low will cause the top of the mast to bend too much, you could also just bang some rivets in the old holes.
 

[jeremyf]

Ah ha, an interesting question.
Tony, I now have an ex Lark Proctor 'c'  which is in great nick, but the spreaders are sooo low.
I was wondering about just copying the height and length from Grimalkins Needlespar ?  I have been looking for a Proctor oriented website that might have suggested positions but thus far without success.
I wasnt going to try geometry for spreader length, just get the mast set up in the right spot / rake and measure  from a tall stepladder.
I also have a 'razor top' needlespar to play with but the spreader length and position are significantly different to the 'original'.
 
 
 

[tonyelgar]

thanks for the input there everyone. Jeremy, im not going to do it unitl one evening next week but i can send u the measurement of my old masts spreader height, which is a proctor c as well, so that should see u about right. From the feedback here i shall be copying it myself now!
 
tony

[tom lee]

have a look at the tuning guide http://www.national12.org/downloads/tuning_guide_revised_2004_v1.pdf there is a table in there with the spreader height for various masts/boats

[jeremyf]

Hi Tony,
Thanks , that would be useful.  As a matter of interest the middle bit of Grimalkins original Needlespar is now my TV Aerial mast- Towers above mere B&Q alternatives !
Tom, Thanks also, thats good - I will compare and contrast with Tonys 'Actual' measurement.