Drew Dalgleish ha scritto:
On Fri, 08 Feb 2008 19:18:53 +0100, Daniele Fua
wrote:


Thank you very much. I have also found few Loos retailers on this side
of the Ocean. Unfortunately I will need both rod and wire gauges and for
a couple of ranges which makes the total purchase rather expensive. The
idea is quite simple so I wonder if it would be very difficult to
construct a device myself; calibration would be an almost impossible
issue but, at least, once the tension of the rig is nearly set at a
correct value by an experienced rigger, a selfmade device could be
helpful in equalling the tensions at both side of the mast and
maintaining it in time.

The mechanical device is for sure the easiest way but... any idea why a
"twang hearing device" would not work? Maybe a piezo pick-up and an
oscilloscope? In any string instrument the change of the pitch is
strictly correlated to the tension (beside the mass/length, the
stiffness coeff., etc etc of course), isn't it?

Daniel

Isn't the tension at both sides of the mast always equal with the mast
leaning to one sise or the other if the stays are tightened unevenly?

This is a good question that made me think. Yes, probably yes! The mast
itself is not able to give any resistance and for an obvious physical
law, in static condittions both shrouds will have equal tension.
Responding to some of you: I am referring to a classic cruiser-racer
sail boat designed by S&S in the 80' with a quite tall rig, LOA 41'. Two
orders of spreaders and only one rod vertical shroud running from the
deck to the outer part of the first spreader. Assuming that the rigger
did the right thing, from the deck I can only operate on two opposite
vertical shrouds and two opposite diagonal. I have read several things
on how to adjust the mast and have a pretty good idea; my original post
was based on the belief that a tension gauge may improve the adjustment
but you make me think that maybe this is not true.
I enjoy very much your comments and advices and thank you all.

Daniel