Darbys Universal Joint
Darbys universal joint was a key improvement
to the sailboard and remains a distinguishing
feature on windsurfing boards today.
Generally, a universal joint is a fastener that
allows two parts to flex with respect to each
other, but not rotate. Darbys universal
joint could swivel as well, allowing the sailor
to drop the sail in the water if necessary, to
steer by tipping the sail, and even to spin the
mast and sail around.
Darby experimented with different ways to attach
the sail to the board. He tried metal and rubber
joints, but they werent flexible enough.
The mast would turn, but it would also pop a hole
through the sail. Its dangerous if
youre in the middle of the ocean, alone,
and the sail doesnt work.
Darby solved his problem using an 18-inch length
of nylon rope and some household hardware. The
rope is both tough and flexible. Its
elastic, like a large, strong rubberband. It bends
and stretches. It can handle a 300-pound pull
and has a tensile strength of 1,000 pounds. And
it lasts a long time.
Some modern windsurfers still use the nylon-rope
universal joint, but most use better materials--like
urethane--that have eliminated the safety problems
that Darby discovered in his early trials. But
Darbys still a believer in his nylon rope.
[The new joints dont] hold up as long
as nylon--only a few years.