Preface: The recently launched International Space Station
Alpha
orbits the earth at an altitude of 249.5. For Captain Cook, a distance
of 1000 miles from land was common. So too for the sailors of The
Race.
The vessels of Cook and The Race differ in many ways. Since
they are different the techniques used to sail and navigate them vary.
We'll look at three differences below.
Our first case involves the method used in tacking a Square
Rigger. One of the characteristics that Cook's Endeavour and The Race
Class catamarans share is that tacking them through the eye of the wind
can be difficult.
Tacking a ship like Cook's involved sails numbering the double
digits and upwards of 50 men. Cook's bluff bowed slow Endeavour also
could easily go into irons.
In tacking a typical modern monohull, you put the helm over,
release the jib as it comes head to wind, and then fall off to the
other tack.
Tacking a square-rigged ship has much more to do with the crew
steering the ship through the tack via sail handling than simply putting
the rudder into action.
To tack from port to starboard, the initial move is to turn the
rudder to the left. As the vessel nears the wind, the square sails luff.
The fore and aft sails on the aft mast are trimmed amidships. This
allows the rudder to turn the stern without opposition. The next step
in the evolution is for the main and mizzen square sail yards to be
tacked. They are then set for the new tack in this case- starboard.
The vessel has now approached head to wind. It is here that
it can be caught in irons. At this point the fore mast square sails
come into use as a steering device. They are left trimmed for the old
tack (port). This trim pushes the bow in the direction you want it
to go, in this case the left.
With three forces now applied to turn the ship (left rudder,
reduced force by overtrimming fore and aft sails, and fore mast sails
pushing) the ships momentum is carried from port to starboard tack.
The foresails stay aback to help the lumbering ship complete the tack.
As the tack is finished the foresails are trimmed properly and the
vessel can now accelerate on starboard.
To tack a square-rigged ship required the crew to be in full
harmony when conducting the various aspects described above. To tack
a Race Class cat is not easy. Still, the numbers are around 15 crew
and 2 sails compared to the square-rigged tack.
One reason for the speed of the Race Class cats is that they
use the wind in a fundamentally different way. How these disparate
vessels ride the wind is our second case.
Cook's Endeavour rode the true wind, which is the wind you
sense if you are at a dead stop. The faster a boat moves the more
'wind it creates'. As the speed picks up the wind moves forward on
a boat and the angle between boat and wind narrows. Since Cook's
ship had limited speed potential, the craft didn't move fast enough
to create much apparent wind.
The Race Class cat's are capable of speeds up to 40 knots, with
averages at 25 and periods of phenomenal acceleration. These make
these craft riders of the apparent wind as their speed is a much higher
percentage of the true wind.
The way in which they ride the wind is shown in the types of
sails carried.
Cook's Endeavour carried square sails that performed best
when being pushed by a following breeze. Endeavour's speed and apparent
wind generation potential was limited. Therefore the sails carried
considerable curve in them.
According to Team Adventure Skipper Cam Lewis, "What we really
need is 18 knots from 110 degrees true wind angle." For the Endeavour
the apparent wind angle would differ little from the 100º true wind
angle. For Team Adventure and her brethren the apparent wind angle
generally is far forward of the beam or 90°.
Therefore they carry a large fore and aft main, a genoa, a
small jib and various types of gennekers. Gennekers are in between
a flat genoa and a much more rounded spinnaker. The maxi marans don't
carry traditional spinnakers. They are creating so much wind and
therefore a narrow apparent wind angle spinnakers are not necessary.
Recently the maxi maran Team Adventure crossed the Bay of
Biscay in gale force winds. Co-Navigator Larry Rosenfield describes
the apparent wind generation of the 110-foot catamaran: "The true
wind was 42 knots and the boat was doing 18 knots with just the storm
jib and the sail area of the wing mast. It created an apparent wind
across the deck of 55 knots."
This is one reason it is conceivable that Race class cats can
sail around the world averaging 15 knots when the average wind speed
on the course is 11 knots. Their boat speed will make up this true
wind deficit by creating the needed power in the form of apparent wind!
The final case pertains to weather forecasting. When Endeavour
sailed, weather information came wholly from onboard. Weather forecasts
were based on how the barometer moved, what the eye saw and what
experience and lore taught. One fared the weather by instinct more
than any type of science.
The maxi marans of The Race will have multiple sources of
weather going far beyond what the crews' eye can see. They can access
wind from floating weather buoys the world over on the internet at
resources such as: http://www.ems.psu.edu/wx/regions/all.html They
can view satellite images from space at places like
http://www.sat.dundee.ac.uk/pdus.html All this via on board
computers.
The speed of the cats will make a difference in weather
prediction. These vessels will be able to outsail the weather.
Cracking on for days at 25 knots will allow them to move faster
than weather systems. On board and ashore weather routers will
have to factor this in.
The purpose of all this weather information is to enable a
competitor a significant advantage on the rest of the fleet.
According to Larry Rosenfield of Team Adventure: "Once people lock
into a weather system, they may be able to sail along with it."
Finding the system and putting in days of 20 and 30 knots when your
competitors aren't could make your group the winner of The Race.