Whoa wait a minute here ......
The whole function of the rigging is to keep the mast in column thus
minimizing compression/buckling failure.
Yes, intermediate stays balance the set tension of the forestay on a
cutter rig; but do not equalibrate the tension balance when the
staysail loads the forestay with the resulant of tending to take the
mast out of 'column'. The functional advantage of runners is that they
are applied only with enough tension to restrain the mast deflection at
the foresty connect, not to 'preload' the forestay .... but yet
adjustable to variable tensions .... as needed - NOT so with
intermediates the set up tension is the tension you get!

With regard to weight aloft the modern 'super-polymers' remove most of
the disadvantage of mass and chafe (to the other wire shrouds) .... and
totally disregarding that they are a total pain in the ass when
tacking/gybing.

With runners, you can position them essentially anywhere you want on
the deck; but, knowing that the pin connection at the extreme aft will
affect the best intercept angles and least amount of adverse strain and
the lightest amount of weight (diameter) since at that position the
need for 'stronger' runners is lessened - again its all in the
trigonometry and the reactive forces.


In article , Roger Long
wrote:

Yes, but why store them on the cap shrouds when not needed and have
the chafe and useless weight? Why not have them functioning as
redundant lower shrouds with enough back angle to help keep the mast
in column against the inner stay?

Unless the inner stay is also removable, there are things other than a
sail that can put loads on it. Missing stays and going aback with the
headsail laying against the innerstay could put a big load on the mast
and put it out of column in an extreme situation. Having the
backstays stowed in a position where they provide some support could
be a rig saver.

The back stays won't do the full job in the forward position but it's
up to you to figure out when the rig needs the extra support. I would
size them to function in the aft position. With normal factors of
safety, they will still be able to do a lot in the forward position.
On thing to be wary of is how much load they can put on the mast in
that position if they, rather than the mainsheet, is taking the load
of the mainsail. This is an issue with all backstays and aft lower
shrouds, however.

BTW, I did the indeterminent structural analysis on the standing
rigging and spars for the Rose, (later the Surprise) in "Master and
Commander" for her U.S. Coast Guard certification. Very cool to watch
the computer bend everything farther and farther and see the shape of
one of these rigs at the point of probable failure.

Also designed the rig and spars (as well as everything else) for this
ship:

http://home.maine.rr.com/rlma/Boats.htm#Barque

Although yacht rigs are pretty far off my radar screen except for my
own boat, I've thought about them a bit over the years.