H336...Mast Rake

[Dmac336]

Recently purchased a '96 336.....the 336 has an exaggerated taper in the mast...boat was shipped over land so rigging was down...upon re- rigging and tuning to where prior owner had it, the bend was huge- around a foot...have since backed it off and have about 6 inches of bend.....sail goes up much easier now but wondering if PO knew something about proper tuning that I don't....?

 

[Alan]

Pre-bend in the mast is set to the luff curve built into the main sail. If you remove too much pe-bend the sail will be too full and you wont be able to remove it in higher wind speeds. Your 336 has a B&R rig which carries more pre-bend than most traditional rigs and because you don't have a backstay you have no way of flattening the sail other than outhaul tension.
Measure the amount of luff curve and use that to set your pre-bend. Forget about how it 'looks' to you, that has no bearing on the tuning. While you're at it don't forget to dial in the proper amount of mast rake. 1 to 2% of mast height will give you a good working number.

 

[Andy1237]

Per the 340 manual "the maximum about of bend should be no more than 8 inches ..Measured perpendicular from the aft face of the mast to the halyard at the deepest part of the bend."

 

[Dmac336]

Thanks...sounds like I've got it within reasonable tolerance.....on another note, main halyard was old and showed severe frayed spots...I replaced it and, after a month, new one is getting a few frays about 3 feet from shackle....feels like sheave is turning ..and since I removed reef lines from sail it goes up easy and drops with ease....what do you think could be causing halyard fraying?