Page 330 - The Complete Rigger’s Apprentice

heavy cat rig. Perhaps because sailors tend to like
sleek, weatherly boats, unstayed aluminum and
wooden rigs have not taken over the market, even
though they are usually far simpler and physically
easier to sail than their stayed brethren.
Carbon fiber, an even more recent mast material
development, is far less elastic than wood or alumi-
num, so it can be used to make masts, unstayed,
that are nearly as deflection-resistant as ones that
are stayed. Carbon fiber is spun from, take a deep
breath, thermally decomposed polyacrilonitrile,
known more familiarly as “PAN.” Filaments of PAN
are pre-stretched, then stabilized with a relatively
mild heat (428 degrees F). Then the filaments are
placed in a nitrogen atmosphere and really cooked
(at about 2,700 degrees F), a process which essen-
tially burns away everything but tough little strings
of carbon.
Sound complicated? Nah, that’s just chemistry.
Figure 8-10. Sail plan of the Freedom 32. The real chore comes in trying to build a mast out
of this stuff. First you have to make it into a kind
free-standing mast, as on Tillotson-Pearson’s Free- of fabric, just so it can be handled. Then you have
dom line of sailboats (Figure 8-10), removes that to lay it onto a form—usually either an aluminum
design challenge; the hull and sail plan are no lon- mandrel or a bladder-filled clamshell mold—under
ger subject to backstay- and shroud-imposed limita- maximally nit-picky levels of heat, pressure, and
tions. But, as is always the case with technology, an tension, in a pattern which has been precisely engi-
entirely different challenge arises from this sweep- neered to produce optimal stiffness and durability
ing solution: how to make an unstayed mast small, with minimal weight or size.
light, and inflexible enough to approximate the per-
formance of a well-designed stayed mast. Mast Bend, Stayed and Unstayed
Unstayed masts are by no means a new idea;
they’ve been characteristic of many traditional craft A stayed aluminum mast can be bowed in the fore-
all around the world since sailing’s beginnings. It’s and-aft plane by tightening the backstay and/or
forestay and/or babystay, with hydraulic or man-
just that until relatively recently they had to be ual adjusters. This action flattens the jib by ten-
made of solid wood, and there was no way to keep sioning the jibstay, and flattens the main by pulling
them from bending excessively under load, thus the sail’s draft forward. This results in improved
efficiency when going to windward, and it delays
compromising sailing efficiency, without making the need to reef because moving the draft of the
them extremely large and heavy, thus compromising sails forward lessens heel and weather helm.
sailing efficiency. Unstayed rigs do not provide the same sail-con-
In this century, hollow aluminum and wooden trol options, or at least not in the same way. Full-
length battens control sail shape (along with the
masts have been developed that are sufficiently vang), preventing the draft from moving too far
light, durable, and deflection-resistant to be useful aft. Reefing is delayed not by flattening the sail,
for sailboats, as long as you don’t care a great deal but by engineering the mast so that the head sags
well to leeward in gusts, effectively depowering the
about efficiency to windward and have a taste for big main.
the fairly tubby hulls you need to hold up a big,

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