It is not particularly adjustable though, and suffers when trying to
tune for balance ...


Wally wrote:
Losing me here - tune for balance?

Well, I was thinking of balance on the helm, which can be very definitely
affected by the trim of the sails and the adjustment of the rig. A masthead rig
is less able to adjust the rig "on the fly" than a fractional rig.



... or to depower without laboriously shortening sail. ...

Well, the main has roller reefing (although I need to sort out a strop for
the kicker), so maybe shortening sail won't be too much of a hassle.

Hmm, how to be tactful while saying this.... roller reefing is more difficult
and less effective than slab reefing.


The jib
is hanked, but rather tatty (needs repairs to the luff).

Have you considered learning sailmakers skills? Fun, passes the time, useful
result.... personally I prefer it to tippity tapping on the computer. But
talking about boats is still fun.


.... I'm thinking of a roller reefing genoa, maybe next year. (My
thinking is that a new jib and a new genoa would cost about the same as a
reefing mechanism and suitable genoa, so the reefng option would make life
easier when I'm single-handing.)

Yes, but consider getting the small jib recut for using with the RF too. The
roller reefing will only take the genoa down one size, maybe two max. You'll
still want a small jib!


Would I be right in thinking that using a small jib with a reefed main on
this rig would move the centre of effort forward?

Yes, definitely. You might want to consider using a small jib set up on an inner
stay. Staysails can make great storm sails.

.. Generally
you want to tighten the backstay as the wind increases, up to the point
where the structure of the boat starts distorting.

The shape of the main would be affected (flattened) as well, wouldn't it?

Yes, two ways: One is that mast bend is increased, which pulls cloth out of the
middle of the sail, and the other is that it brings the mast tip closer to the
boom, which opens the leach (assuming that the sail is not sheeted down harder).


For an 18' boat how much would the top of the mast typically come aft?

Depends on the backstay adjuster, the stiffness of the hull, and the muscles of
the person working the backstay adjuster Could be 8cm or more, 2 or 3 cm is
more likely.

FWIW,
it also has a sliding gooseneck and (shortish) tracks for the jibsheet
fairleads.

All good ways of getting more effective sail shape. Remember that as you honk
down the gooseneck, you tighten the leach but you also lower the boom and reduce
the leverage of the vang (also known as the kicking strap).


These are double lowers. .... The foreward pair
of lowers should be the tighter.

Do you mean that the mast is set to tilt forward slightly? Or that the
forward lowers have tension because they're working against the backstay?

The latter, plus you want the mast to bow foreward, not aft. This is one reason
why you want a backstay adjuster, to help pull the forestay tight so the jib
luff won't sag as much. With most jibs, this is very important for pointing
(getting the finest angle going to windward).



Yup, I can see how there's a bunch of triangulation going on - atfer sailing
dinghies last year which only had a forestay and the masthead shrouds, this
set up does give the impression of being stronger and stiffer.

It is but remember two things: 1- overall, tension must equal compression. The
stays work by trying to push the mast down through the hull, or alternately
trying to bend the boat like a banana. Banana shaped boats generally suffer
sailing performance! 2- if one part of an assembly is very strong or stiff, it
will throw more strain on the next part. Sailors often tend to forget one or the
other, thus gaining personal insights about Murphy's Law.

Fresh Breezes- Doug King