12-Apr-2002 -- After having loaded at San Antonio on 07-Apr-2002, we
began our voyage with our Argentine lemons, apples, pears and grapes to
Petersburg, Russia, 8,000 nautical miles nonstop.
Especially the beginning of a trip from South America to Europe is always
bothersome. Due to the strong Brazil current setting against, you are
creeping with reduced speed for several days along the coast of Brazil and
the trip seems indeed to be
In order not to die of boredom during such a voyage, we decided to see some
confluences en route.
With the first one, on 23°S / 42°W, it was clear from
the very beginning it could remain only an attempt for us, as it is on land
and not reachable by ship. But as this point has been already successfully
visited, it's not as bad as all that.
The only thing we could do is to pass the Island of Cabo Frio in a safe
distance and make a picture of it. The
south-westernmost tip of the island itself is called Cabo Frio (the "Cold
Cape"). There is a conspicuous lighthouse on it. The
confluence is 140 m above sea level and almost exactly on
top of the
ridge connecting the two highest elevations of the island (390 m in the East
and 250 m in the South-West). In order to identify the point with maximum
accuracy first we adjusted it in
the radar and then Captain Peter found its correct
direction ("azimuth", as the navigators use to say) by a gyro compass
Probably the confluence is not visible from the ship, but just a little bit
over the ridge toward NE.
Our GPS shows a closest position of 23°01,111'S and
41°58,582W, i.e. a 3,300 metres off the confluence at 12:38hrs, but that
being not of significance under the prevailing circumstances, as there was
anyway no chance for us to go to the point, due to the beforementioned
Ilha do Cabo Frio is separated from the mainland by a very narrow passage,
135 m wide, called Boqueirão. It is spanned by an overhead cable.
The closest town is Arraial do Cabo, a fishing and salt loading port.
The hinterland is full of salt pans. See the chequered areas on the chart.
The lighthouse on Cabo Frio gives us the opportunity to think about
lighthouses in general.
Lighthouses are not just simple candles, they are rather complicated and
have a long history:
Already in ancient times experiments with lighthouses took place. But their
brightness was frequently left to the chance. Unprotected open fires on
towers were flickering irregularly, sometimes brighter, sometimes darker.
In 1765 an 18 year old French, Antoine Laurent Lavoisier, discovers that a
source of light in the focus of a parabolic mirror is reflecting all rays
parallelly. That is the basis of all modern lights, from the brightest
floodlight over the cars' headlights to the smallest torchlight.
In 1822 another French, Augustin Fresnel, constructs the first lens named
after him. This lens is focussing the beams of the light as a parabolic
mirror, but is concentrating it additionally in the horizontal direction.
Fresnel developed a lens formed like a collection of belts, grinded
horizontally and not perfectly circular. Several of these horizontal
grindings added together are focussing the light of a single source parallel
to the surface of the sea. Now no light could go lost any longer.
With the Fresnel-Lens France established a powerful position. They had the
monopoly for its production. Whoever was in need of safe lighthouses had to
purchase them in France. After the victory of Germany over France in 1871
the French had to deliver Fresnel-Lenses as war-reparations to Germany. This
fact underlines the importance of these lenses.
Lighthouses with a high range are a beautiful thing. But soon, after the
middle of the 19th century, there are so many lighthouses along the coast of
Europe that it becomes difficult to distinguish them. This problem has been
solved by different colors and codes. Lightouses were then blinking and
flashing with different interruptions.
Cabo Frio lighthouse for example has a code of "Fl.10s144m49M"
A white flash every 10 seconds. The height of the light is 144m above sea
level, and the reach or visibility of the light is 49 n. miles (90,7 km). It
is an extremely strong light.
The source of the light changed as well. In 1885, an Austrian, Auer von
Welsbach, invented the glowing stocking. With a gas-air-mixture he makes a
silk stocking to glow. But then electrification takes place.
The first electrically powered lighthouse was built in France in 1865, on
Cap de la Hève, near Le Havre, on the entrance of River Seine.
All light houses of the World are listed in the "Admiralty List of Lights
and Fog signals" of the British Admiralty.
Fresnel-Lens drawing from "Dienstanweisung für Leuchtturmwärter" (Procedures
for Lighthouse Wardens), 1893,
Pohl, Dr. F.-W., "Die Geschichte der Navigation", Koehler, Hamburg 1999