I've been the grateful benefactor of Dave Philpott's generosity and I'm trying to figure out the set up involved in putting a newer mast on an old hull, to possibly use more recent sails.

I'll start with some dimensions which might make sense to those who know.

All from the sheerline. (The mast gate is 200mm above the sheerline  on the phantom kipper)

Gooseneck centreline 630mm
Upper edge, lower band, 730mm
Lower edge, upper band, 6390mm (giving the 5720 Luff)

Spreaders (300mm long) 3345mm
Shrouds 4775mm (also a pair of higher holes at 5140mm)

Jib box, top of sheave, 4690mm
Spinnaker box, top of sheave, 4870mm

So, questions are, Jib box - is it too high to maximise the benefit of modern jibs - I've seen threads suggesting it should be lower, and use a 2:1 set up.

Shrouds - should they be using the higher locating holes?

Spreaders, are they too high (the existing mast has 400mm spreaders at 3100mm and shrouds fixed at the higher 5150mm position)
I understand they will need to be angled back to suit the deck level location of the shroud quadrants. Is there a reccomended amount of deflection for the older boats or is the deflection dependant on the type of mast?

I understand there won't be alot of rig tension available, and I'd prefer not to drill more holes than necessary in the mast. (is there a reccomended way of dealing with redundant holes in alloy masts?

Is there anyone who recognises the dimensions as being workable on an older hull?

Thanks

I wouldn't start moving the spreaders, hounds or jib box around, it will weaken the mast and it will probably break.

The M2 is a pretty fierce mast probably similar, but i'd say still stiffer, than the old Beta Minus. In fact thinking of it it's probably akin to the older B section, though probably much lighter. 

Moving the jib box isn't really going to help, and i'd tend to use the lower hounds. Best bet is to work with what you have as the standing rigging measurements off new masts is going to be optimised for a very flexible carbon mast.

Spreaders will be trial and error i'm afraid! The shroud bases vary between the differant builders, but what you basically want is for the mast to assume some bend when you put the tension on.

Bit concerned about the gooseneck being at such a different height to the Lower band.

When the boom is on the gooseneck, the tack of the sail cannot be below the band. So while the gooseneck may be lower at 630mm, the sail must not be capable of being less than 100mm above it at 730mm.

The gooseneck is usually positoned such that the top of the boom is at 729mm.  According to the type of boom this may entail the gooseneck being a few mm lower - but not 100mm.

Something needs checking here..

GGGGGGG

Also can't make out the spin halyard position.  Should be as high as possible at 4220 above the lower band, ie 4950mm above your sheerline.

GGGGGGGGG

Kieron
Suggest that you give me a call so that I can come and have a look at it for you.  Probably the best thing to do is try it as it is before making any changes.
Richard

RE: Measurement Man

I'm sure your observation will be correct - but with the absence of a boom to go with the mast the centreline of the gooseneck was set at 630mm as being towards the lower end of the tollerance, while the band was already in situ to suit the sails and presumably the old certificate for the donor boat. 
The upper edge of the boom  would be set to the black band when a boom and sails become available. 
Hope it is a reasonable explanation,

Re: RichardT

Thanks Richard, the first step will be to get on the water with the existing proctor mast which is ready to go with the older sails. Ill bring this other mast along as well to have a trial set up but will need to get the mast below the sheerline extended first - its about 150mm short of reaching the hog at the moment, based on the other dimensions being corect (sheerline to gooseneck/bands etc. The proctor mast seems to have been the same originally as that has a 150mm section added at the bottom - will keep you posted about the return, but as usual the little bit of flaking varnish lead to more work!

Hi - just remembered it was probably the first mast fitted onto 3291 by its first owner/builder - Laurie Smart. Might be worth a call??

Hi Dave, i'm sure it will work out very well - thanks again.