basic mast-stepping question

[dnf777]

Hi All,
I may win the dumb-question of the year award for this one, but here goes....

How do you really know, with precision, that your mast is properly stepped, perpinducular and square to the hull?

A little background in my particular case: Precision-15 fractional-sloop, with a forestay (jib furler) and a shroud each side with back-swept spreaders and quick-release adjustable shroud tensioners. I doubt many with such little dinghys worry this too much, but how do I really know the mast is square and true.....just by looking? Its like several people looking at a picture and arguing whether its hanging straight or not??!! Never all agree.

I suppose I could tie a string to the mast head (or secure the halyard) and make sure it hits the chainplates at the same point on both sides for lateral trueness, but what about fore/aft? I don't assume the angle with the deck is reliable, as the deck may not be true to the hull line.

Thanks!

[WanderingStar]

Laterally, the "string" method works, but use a steel tape measure. String stretches. Fore and aft I judge by the helm feel when sailing: too far aft will give weather helm. I'm sure others will add good ideas.

[Sublime]

I use the main halyard on mine. I cleat one end and take the dangly end and pick out two spots equal distance from the mast on deck (chain plates, or on mine I use where the struts connect to the deck). I bring the halyard over to one spot after having adjusted the length so it just touches that spot, then to the other and make sure it's equal. If it isn't the same (halyard doesn't touch one side or goes over one side), your mast isn't straight.
I also hang something from the halyard as a plumb bob to check for mast rake. On my boat, it should hang 4-6" aft of the mast step.

[Flybyknight]

Consider a 1 to 3 degree rake in your mast, then with your halyard, it's simple geometry.
Dick

[bobperry]

The truth is: It doesn't matter until you find out what your helm characteristics are like. If you have weather helm, most boats do, then you need less rake. If you have lee helm then you nooed more rake. This is rare.

Mast rake is purely a function opf the helm pressure you want to feel. There is no "one answer".

[dnf777]

Thanks all. Had a great day on the local lake yesterday, with perfect winds. I've only been at this for a year, but handled 15kts, g20 with only a little pucker factor now and then. Really had the P15 cutting a wake! What they say is true--7kts in a sailboat can be much more exhilarating than 60kts in a powerboat! (and not as noisy)

I don't know if my mast was perfectly tuned, but all in the world certainly seemed RIGHT for a few hours!

[eherlihy]