Nossa vida mudou da água pro vinho! - The Bridge 2

Rio de Janeiro visto de Jurujuba - 2017 -  foto de Easy Rider

- Estou tão feliz, amigas e amigos deste oceânico blog, que vocês nem imaginam.

- Acreditam que içamos em fim e pela primeira vez as velas do "Yankee Bravo" e navegamos até a

Atoll 23 à venda em ótimas condições.

Velas ao vento - 2013 - foto de Fernando Costa

- O objetivo desse blog não é, nunca foi, nunca será vender barcos, mas sei de alguém que está vendendo um Atoll 23 pronto pra velejar.

- Liguem [(21) 9 98480 9686] ou escrevam [fernandocosta2002@yahoo.fr) pra mim e conheçam sua ficha técnica preenchida por seu proprietário.

- Se o assunto lhe interessa, amigo leitor, volte a ler este post mais tarde, quando eu tiver acrescentado mais detalhes a respeito.

Fernando Costa

Como velejar um barco

link-da-imagem

- Pesquisando um assunto bem diferente acabei encontrando um roteiro que pretende ensinar quem não sabe, a velejar, ao longo de alguns poucos passos.

- Começa assim ó:

"Há séculos, o mar instiga o espírito aventureiro de marinheiros do

The condition of the SEA - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

image link

"The effects of waves on a ship vary considerably with the type of ship, its course and speed, and the condition of the SEA. A short vessel has a tendency to ride up one side of a wave and down the other side, while a larger vessel may tend to ride through the waves on an even keel. If the waves are of such length that the bow and stern of a vessel are alternately riding in successive crests and troughs, the vessel is subject to heavy sagging and hogging stresses, and under extreme conditions may break in two. Achange of heading may reduce the danger.

Because of the danger from sagging and hogging, a small vessel is sometimes better able to ride out a storm than a large one."

CHAPTER 32 WAVES, BREAKERS AND SURF

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

The SEAS - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

image link

"As the bar approaches, the barometer falls more rapidly and wind speed increases. The SEAS, which have been gradually mounting, become tempestuous. Squall lines, one after the other, sweep past in ever increasing number and intensity."

CHAPTER 35 TROPICAL CYCLONES

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

Blowing across the SEA - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

Oceano Atlântico - 2013 - foto de Fernando Costa

"The stress of wind blowing across the SEA causes a
surface layer of water to move. Due to the low viscosity of
water, this stress is not directly communicated to the ocean
interior, but is balanced by the Coriolis force within a
relatively thin surface layer, 10-200m thick. This layer is
called the Ekman layer and the motion of this layer is
called the Ekman transport. Because of the deflection by
the Coriolis force, the Ekman transport is not in the
direction of the wind, but is 90° to the right in the Northern
Hemisphere and 90° toward the left in the Southern
Hemisphere. The amount of water flowing in this layer
depends only upon the wind and the Coriolis force and is
independent of the depth of the Ekman layer and the
viscosity of the water."

CHAPTER 31 OCEAN CURRENTS

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

The familiar land and SEA breezes - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

Oceano Atlantico - 2013 - foto de Fernando Costa

"The specific heat of seawater decreases slightly as salinity increases. However, it is much greater than that of land. 

The ocean is a giant storage area for heat. It can absorb large quantities of heat with very little change in temperature. This is partly due to the high specific heat of water and partly due to mixing in the ocean that distributes the heat throughout a layer. Land has a lower specific heat and, in addition, all heat is lost or gained from a thin layer at the surface; there is no mixing. This accounts for the greater temperature range of land and the atmosphere above it, resulting in monsoons, and the familiar land and SEA breezes of tropical and temperate regions."

CHAPTER 30 THE OCEANS

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

Mariners at SEA - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

"Mariners at SEA, because of their professional skills and location, represent a unique data collection capability unobtainable by any government agency. Provision of high quality navigational and oceanographic information by government agencies requires active participation by mariners in data collection and reporting.

 Examples of the type of information required are reports of obstructions, shoals orhazards to navigation, unusual sea ice or icebergs, unusual soundings, currents, geophysical phenomena such as magnetic disturbances and subsurface volcanic eruptions, and marine pollution.

 In addition, detailed reports of harbor conditions and facilities in both busy and out-of-the-way ports and harbors helps charting agencies keep their products current. The responsibility for collecting hydrographic data by U.S. Naval vessels is detailed in various directives and instructions.

Civilian mariners, because they often travel to a wider range of ports, also have an opportunity to contribute substantial amounts of valuable information."

CHAPTER 29 HYDROGRAPHY

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

Positions at SEA - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

"The purpose of ship reporting systems is to monitor
vessels’ positions at SEA so that a response to any high-SEAS
emergency can be coordinated among those nearest and
best able to help. It is important that complete information
be made available to search and rescue (SAR) coordinators
immediately so that the right type of assistance can be sent
to the scene with the least possible delay.

For example, a medical emergency at sea might require
a doctor; a ship reporting system can find the nearest vessel
with a doctor aboard. A sinking craft might require a vessel
to rescue the crew, and perhaps another to provide a lee. A
ship reporting system allows SAR coordinators to quickly
assemble the required assets to complete the rescue."

CHAPTER 28 - MARITIME SAFETY SYSTEMS

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

At SEA - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

image link

"As with all VHF transmissions, AIS range depends on the antenna height, and since the wavelength is slightly longer than radar, AIS signals tend to cross land and other obstructions moderately well. The use of shore-based repeater stations can greatly enhance the range and strength of the signals. At SEA, ranges of about 20 miles can be expected."

CHAPTER 27. NAVIGATION REGULATIONS

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

The rougher the SEA - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

image link

"With a sextant, altitudes are measured in the usual manner. If in a small boat or raft, it is a good idea to make a number of observations and average both the altitudes and times, or plot on graph paper the altitudes versus time. The rougher the SEA, the more important this process becomes, which tends to average out errors caused by rough weather observations."

CHAPTER 26 EMERGENCY NAVIGATION

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

Open OCEAN - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

image link

"Just as the navigator must prepare charts for piloting, he must also prepare his small scale charts for an open OCEAN transit. The following is the minimum chart preparation required for an open OCEAN or offshore coastal transit.

Correcting the Chart: Correct all applicable charts through the latest Notice to Mariners, Local Notice to Mariners, and Broadcast Notice to Mariners. Ensure the chart to be used is the latest announced edition.

Plotting the Track: Mark the track course above the track line with a “C” followed by the course. Similarly, mark each track leg’s distance under the course line with a “D” followed by the distance in nautical miles.

Calculating Minimum Expected, Danger, and Warning Soundings: Chapter 8 discusses calculating minimum expected, danger and warning soundings. Determining these soundings is particularly important for ships passing a shoal close aboard. Set these soundings to warn the conning officer that he is passing close to the shoal. Mark the minimum expected sounding, the warning sounding, and the danger sounding clearly on the chart and indicate the section of the track for which they are applicable.

................

Marking Chart Shift Points: Mark the chart points where the navigator must shift to the next chart, and note the next chart number.

Examining Either Side of Track: Highlight any shoal water or other navigational hazard near the planned track. This will alert the conning officer as he approaches a possible danger."

CHAPTER 25. NAVIGATION PROCESSES

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

Normal OCEAN routes - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

image link

"Dead reckoning involves the determination of one’s present or future position by projecting the ship’s course and distance run from a known position. A closely related problem is that of finding the course and distance from one known point to another. For short distances, these problems are easily solved directly on charts, but for trans-oceanic distances, a purely mathematical solution is often a better method. 

Collectively, these methods are called The Sailings.

Navigational computer programs and calculators commonly contain algorithms for computing all of the problems of the sailings. For those situations when a calculator is not available, this chapter discusses hand calculation methods and tabular solutions. Navigators can also refer to NIMA Pub. 151, Distances Between Ports, for distances along normal OCEAN routes."

CHAPTER 24 THE SAILINGS

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

The observer is at SEA level - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui.

image link

"Distance by vertical angle between the waterline
and the top of an object is computed by solving the
right triangle formed between the observer, the top of
the object, and the waterline of the object by simple
trigonometry. This assumes that the observer is at SEA
level, the Earth is flat between observer and object,
there is no refraction, and the object and its waterline
form a right angle. For most cases of practical significance,
these assumptions produce no large errors."

CHAPTER 22 CALCULATIONS AND CONVERSIONS

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui.

STELLA (System To Estimate Latitude and Longitude Astronomically) - My favorites quotes from the famous Bowditch 21

Leia uma explicação para esta série de 30 posts clicando aqui

"U.S. Naval navigators have access to a program called STELLA (System To Estimate Latitude and Longitude Astronomically; do not confuse with a commercial astronomy program with the same name). 

STELLA was developed by the Astronomical Applications Department of the U.S. Naval Observatory based on a Navy requirement. The algorithms used in STELLA provide an accuracy of

At SEA - My favorites quotes from the famous Bowditch

Leia uma explicação para esta série de 30 posts clicando aqui

image link

"At SEA, as well as ashore, watches and clocks are
normally set to some form of zone time (ZT). At SEA the
nearest meridian exactly divisible by 15° is usually used as
the time meridian or zone meridian. 

Thus, within a time zone extending 7.5° on each side of the time meridian the time is the same, and time in consecutive zones differs by exactly one hour. The time is changed as convenient, usually at a whole hour, when crossing the boundary between zones.

 Each time zone is identified by the number of times the longitude of its zone meridian is divisible by 15, positive in west longitude and negative in east longitude."

CHAPTER 18 - TIME 

BOWDITCH

THE AMERICAN PRACTICAL NAVIGATOR

Leia uma explicação para esta série de 30 posts clicando aqui