What causes this rotation? Damned muscle power, ropes, blocks and sea
shanties!!

Then in the late 1800s / early 1900s Jarvis invented the 'Jarvis
winch' - some ships still have working ones - Kruzenshern (ex-Padua
1926), and Stad Amsterdam (2000) are two ships that spring to mind.
This machine allows all 5 or 6 yards on a mast to be pulled round
together - and using the mechanical advantage of 5 or 6 conical drums
geared together to which the braces are wound makes the job easier.

The yards are not brought round so that the wind is directly behind
because then the sails in front would not gain any power from the wind
- being in the shadow of the sails on the upwind mast so to speak. The
idea is to have the wind coming in from an angle so that it hits all
of the sails.

Once the yards are braced they are not exactly in line. They are
slightly off-set in a sprial arrangement whoch apparently draws more
power from the wind.

Hope this helps a little.

CJB

(Brian Louisos) wrote in message . com...
Hi, I'm a complete newcomer to anything sailing related, maybe someone
can answer my question. On a large ship, say an 17-18th century 3
masted marine vessel, I've seen in pictures and movies, that the sails
will rotate relative to the ship to face the wind at the desired
angle. My question is what causes this rotation. I first thought that
it happened naturally, but no, there has to be a way to control it.
Are the entire masts themselves rotated? perhaps just the cross-beams
(sorry I don't know the proper term) are re-angled? Is their a typical
arrangement or do they vary? is this done with ropes, or maybe levers?
thanks for any help.
-bl