"DSK" wrote in message

It's a masthead sloop, also called a Bermuda or Marconi or jib-headed rig
because of the triangular sails, as opposed to a gaff or sprit rig with
quadrilateral sails.

Okay.


I'd also be interested in hearing
comments on it.

OK: it's a very common rig because it's cheap & sturdy (given a suitable
level of technological/industrial development). It is relatively
weatherly,
meaning that it's efficient going upwind, and can stand up to a wide range
of conditions.

Sturdy is good...


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

Losing me here - tune for balance?


... 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. The jib
is hanked, but rather tatty (needs repairs to the luff). Rather than replace
the latter with another standard jib, and maybe find myself wanting a genoa
as well, 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.)


... Also it can
only fly masthead foresails & spinnakers.

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?


The inverted "Y" is for adjusting the tension of the backstay, which will
affect mast bend slightly and foresail shape & trim noticably. 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?
For an 18' boat how much would the top of the mast typically come aft? FWIW,
it also has a sliding gooseneck and (shortish) tracks for the jibsheet
fairleads.


These are double lowers. Their function is to restrain the lower section
of the mast from bending the wrong way, or bowing alternately one way
then the other (pumping), either of which can result in the mast falling
down.

Ah, hadn't though of the pumping thing.


The double
lowers can also be used to induce a slight bend in the mast which can then
be exaggerated or relaxed with the backstay tensioner. 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?


There is also a shroud on each side in line with the mast, passing
over the spreader and going up to the top.

These are the upper shrouds, and are used to control the side-to-side bend
of the mast (although the lowers also influence this). Think of the mast
with
it's shrouds as the same sort of girder as a webbed panel in a bridge: the
mast & spreader is in compression, the shrouds are under tension, the
whole
is a rigid assembly that can take either a little or a lot of force
without
bending too much or breaking.

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.



I demand rigidly-defined areas of uncertainty!

I like that slogan. How about this one: "I have no respect for
conventional tokens of disrespect!" ?

I'll keep that in mind for potential future use. :-)


--
Wally
I demand rigidly-defined areas of uncertainty!
www.art-gallery.myby.co.uk