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Salty Dog
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PostPosted: Sat Apr 22, 2017 3:08 pm    Post subject: Pirate Navigation Reply with quote

Pirate Conning
By Cindy Vallar




. . . they put out to sea when they were equipped for the voyage, and sailed for three days, until the land was hidden by the water. Then the fair wind died out, and north winds arose, and fogs, and they knew not whither they were drifting and thus it lasted for [a long period of time]. Then they saw the sun again, and were able to determine the quarters of the heavens; they hoisted sail, and sailed . . . through before they saw land. They discussed among themselves what land it could be and [one of them] said that he did not believe that it could be Greenland. (Wigal, 22)


This passage from Leif Eriksson’s Saga of Erik the Red demonstrated the primitiveness of early navigation. Few ships ventured out of sight of land. Their navigators relied on landmarks, tides, nature, and other simple indicators to safely reach their destinations. This method remained a stalwart of navigation until inventors found a way to calculate longitude in the eighteenth century. Until then they practiced “running down the latitude” as Amerigo Vespucci wrote in 1597, “We sailed with the northwest wind, thus running along the coast with the land ever in sight . . .” (Wigal, 56) and William Dampier, a buccaneer, recorded a century later.


We steered away NW by N intending to run into the latitude of the Isles Galapagos and steer off west, because we did not know the certain distance, and therefore could not shape a direct course to them. When we came within 40 minutes of the Equator we steered west. (Preston, 107)
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Salty Dog
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PostPosted: Sat Apr 22, 2017 3:10 pm    Post subject: Reply with quote

“Running down the latitude” meant a ship sailed north or south within sight of land until it reached a latitude that was the same as where the ship wished to end up. Then she sailed east or west, while the navigator regularly checked their course while the helmsman steered according to the sea artist’s instructions.1 To steer a vessel before the twelfth century an oar was hung over the side and the helmsman turned this steering oar to increase or decrease the drag. The Vikings maneuvered their longships this way. From the 1100s onward, the hinged rudder replaced the steering oar. Rather than being located on the side of the vessel, the rudder was located on the stern beneath the water line. Once tillers, whipstaffs, and steering wheels were added, shipwrights could design newer and larger vessels.


This ship is using a steering board


This ship has a rudder
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PostPosted: Sat Apr 22, 2017 3:12 pm    Post subject: Reply with quote

Whipstaffs were first used during the 1400s. They were located at a higher height than the ship’s tiller, to which they were attached, but not too far from it. (The tiller was connected to the rudder.) With the whipstaff situated inside a cabin or below the main deck, a window provided the helmsman with a view of the sails, rather than what lay ahead on the ocean. Lookouts relayed needed information, while the navigator stood on the deck above the steerage cabin and gave instructions through a speaking tube. The center pole in the left picture replicates the Mayflower’s whipstaff. The compartment in front of it was the “bittacle,” which housed the compass. The picture in the center shows an upclose view of the Elizabeth II's whipstaff (one of Sir Walter Raleigh's ships that brough colonists to Roanoke Island). The right picture shows an exterior view of the cabin where the helm was located below the quarterdeck and after of the capstan.
The first evidence of a steering wheel on a ship dates to 1705, although its invention came in the previous century. The difference between this and the whipstaff was the helmsman now stood on the quarterdeck where he could see both sails and ocean, but not necessarily what lay ahead of the ship. The wheel provided him with greater accuracy and more maneuverability in doing his job, but unlike his predecessors he was on an open deck. If it rained, he got wet. If a wave washed over the stern, he might get swept overboard. If the sun beat down on a hot day, his skin burned. [/img]
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PostPosted: Sat Apr 22, 2017 3:13 pm    Post subject: Reply with quote

Landmarks were essential to seamen. William Dampier2 wrote in A New Voyage Round the World:


On the back of the town, a pretty way up in the country, there is a very high mountain, towering up like a sugar-loaf, called Monte Christo. It is a very good sea-mark, for there is none like it on all the coast. The body of this mountain bears due South from Manta. About a mile and half from the shore, right against the village, there is a rock, which is very dangerous, because it never appears above water; neither doth the sea break on it, because here is seldom any great sea; yet it is now so well known, that all ships bound to this place do easily avoid it. A mile within this rock there is good anchoring, in 6, 8, or 10 fathom water, good hard sand, and clear ground: and a mile from the road on the west side, there is a shoal running out a mile into the sea. (123-4)


Another example of a landmark was the Cayman Islands, which was how mariners used the islands. Only later did they stop there to restock supplies or repair their ships.
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PostPosted: Sat Apr 22, 2017 3:14 pm    Post subject: Reply with quote

Aside from an acquaintance with landmarks, a navigator had to know the weather patterns. The monsoons, for example, influenced the direction and times when ships traveled to and from the East Indies. The Spanish treasure fleet schedules were theoretically timed to minimize the dangers from hurricanes from midsummer into fall. Majority vote, not the captain or the sailing master, determined what course the pirates sailed. John Lambert held this latter position aboard Sam Bellamy’s Whydah. Alexander Selkirk served as navigator aboard the privateer Cinque Ports before his marooning on Juan Fernandez Island. Four and a half years later, Woodes Rogers rescued him in February 1709 and among the belongings he brought aboard this privateer were “his Mathematical Instruments,” tools used in the art of navigation.

Rogers’ navigator on the Duchess was none other than William Dampier, chosen because of his knowledge and experience, “the only living Englishman to have been thrice and twice around the world.” (Preston, 310) These three privateers would be among those who captured a Manila galleon, whose hold contained “jewels, silver plate, musk, cinnamon, cloves . . . silks, damasks, and Chinese porcelain,” which would eventually bring £150,000 at auction. (Preston, 320)
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PostPosted: Sat Apr 22, 2017 3:15 pm    Post subject: Reply with quote

When Bartholomew Roberts captured the Samuel, he discovered Henry Glasby of Scotland whose sea artistry skills surpassed Roberts’ current navigator, Nicholas Thomas. Glasby wasn’t interested in going on the account.


He tried to hide but the pirates found him, beat him and threw him aboard their vessel. He refused to sign the articles but was “cut and abused very much”. In the end he complied and this most reluctant of pirates would play a central role in Roberts’ story from this time on. (Sanders, 115)


Following the death of Roberts and the capture of his men, Glasby, who had been aboard the Royal Master for more than a year and a half, was tried in the Great Hall of Cape Coast Castle on 2 April 1722. One witness, Captain Traherne of the King Solomon, swore:


The pirates “did as they would . . . never observing him” . . . he was a prisoner, that he had striven to rein in the excesses of the pirates, and that, when he could, he had returned stolen goods to their owners. He was “civil beyond any of them”, said John Wingfield. (Sanders, 232)


Other witnesses – including acquitted pirates – supported this testimony. The court acquitted Glasby, but considered “his evidence would be of great use . . . for trying the remaining pirates”. (Sanders, 232)
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PostPosted: Sat Apr 22, 2017 3:16 pm    Post subject: Reply with quote

While ships today often take the most direct (or shortest) route, that option wasn’t available to ships that relied on sail to reach their destinations. The wind determined when and where they could go. One area seamen preferred to avoid, although it wasn’t always possible, was the “doldrums.” This was a region, anywhere between fifteen and 150 miles wide, above and below the equator. There was little wind and the air was often oppressively hot and muggy, although a hurricane, squall, or thunderstorm could occur with little warning. French sailors called this area le pot au noir (the black hole). A vessel caught in this region was often becalmed, unable to move, which put the crew and passengers at risk. When food and water became scarce, those aboard pooled rations and went on short allowance, meaning they had access to small portions of these resources at specified times. John Cox and his fellow buccaneers found themselves in such a situation in 1680. Water became so precious it sold for “30 pieces of Eight per Pint.” (Little, 116) The infrequent allocations were never enough to sate one’s appetite. This led some to steal from the precious stores. One pirate did so while crossing the Pacific in 1686. Upon discovery, he suffered “three Blows from each Man in the ship, with a Two-Inch and a half Rope3 on his bare Back." (Little, 117)

If the wind didn’t reappear and their supplies ran out, the pirates could die. This was why ships in the Age of Sail sailed along specific regions of the oceans. Above and below the doldrums were constant winds, which became known as “trade winds” (or “trades”) because ships relied on these to transport trade goods from one country to another. Established trade routes served as prime hunting grounds for pirates. Nowhere was this truer than the Windward Passage, located between Hispaniola and Cuba – the last stop for treasure fleets bound for Spain. Off the coast of Hispaniola lay Tortuga, which the buccaneers used as their haven in the seventeenth century. This location made ships traversing the Windward Passage rich pickings for the pirates.

Closer to the poles, the winds blow from the west and are known as “westerlies.” In between the trade winds and the westerlies are the “variables,” where unreliable winds blow. These latitudes are sometimes called the “horse latitudes” because of how the lack of wind and stifling heat affected horses being transported to the Americas.
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PostPosted: Sat Apr 22, 2017 3:17 pm    Post subject: Reply with quote

Knowledge of the winds, however, was only one example of a navigator’s tools. Sea maps, called “charts,” provided details for a ship’s safe passage through a body of water. They contained coastal outlines and landmarks, as well as information on depth soundings, tides, and currents. But early maps often distorted or misplaced continents because much of the world remained unexplored. Known regions, such as those that Spain claimed, were mapped, but these maps were jealously guarded from other countries. One of the most prized treasures pirates and early privateers sought when capturing Spanish ships were sea charts. Those of the western coast of South America were unknown to Englishmen until Bartholomew Sharp captured the Santa Rosario in July 1681.


In this prize I took a Spanish manuscript . . .. It describes all the ports, roads, harbours, bays, sands, rocks and rising of the land and instructions how to work the ship into any port or harbour. They were going to throw it overboard but by good luck I saved it – and the Spaniards cried out when I got the book. (Rutherford-Moore, 1Cool



The confiscation of these charts proved invaluable, for when Captain Sharp gave them to the king, the pirates were pardoned. Once translated and copied, the navy and merchant marine used these sea charts to sail in Spanish waters. Blackbeard also found them valuable, for he appropriated Henry Bostock’s “cargo of cattle and hogs, his arms, books and instrument” on 5 December 1717. (Konstam, 165) The books most likely included a waggoner, while the instrument was probably a backstaff, a navigator’s tool used to calculate latitude.

The first sea charts appeared in the thirteenth century. About 300 years passed before anyone gathered them together in a single book called a “waggoner.” The name stemmed from Lucas Janszoon Waghenaer, who published Speighel der Zeevaerdt in 1584. Four years later, an English translation appeared entitled The Mariner’s Mirror. It became so popular English seamen referred to it as a “waggoner” and the word came to mean any sea atlas
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PostPosted: Sat Apr 22, 2017 3:20 pm    Post subject: Reply with quote

Aside from these sea charts, navigators employed various instruments to determine a ship’s location and speed. The magnetic compass indicated direction and was essential for steering a steady course. Early versions were merely magnetized needles that pointed north while suspended from a string. Later the needle was mounted on a pivot, and by the 1500s, a round card was fixed to the needle. To prevent inaccurate readings, however, the navigator and helmsman had to remove their knives around the steering compass, located in the binnacle.

To determine how fast a ship sailed, a log line (knotted at regular intervals) was heaved overboard from the bow. At the same time a thirty-second sandglass – also called a sand clock – was turned over. Once the sand ran out, the line was hauled back in and the knots were counted. This information was put into a calculation to determine the speed of the vessel, which was then recorded in the log book or on a traverse board, a wooden board into which pegs were inserted. The right-most picture above portrays one similar to that aboard the Mayflower, which was located behind the helmsman. A ship’s day began at noon and was divided into four-hour periods called watches. During each watch, a seaman placed pegs in the appropriate holes on the traverse board to record the ship’s direction and speed.

When a vessel came near land, the crew took soundings to determine how deep or shallow the water was.4 The leads-man (sometimes more than one) secured himself to the bow of the vessel and heaved the line, attached to a lead weight, forward. Sometimes he called out the knots as they passed through his hands; other times, he counted them as he hauled in the line. This information was shouted to the captain near the helm. To determine what type of seabed was beneath them, the leads-man first applied wax or tallow to the weight. Sand or mud indicated a soft bottom, but a clean one indicated hidden dangers such as rocks or reefs.

Navigators also used books of tables and sailing directions. The earliest known navigation manual was printed in Lisbon around 1509 and called Regimento do Estrolabio. Tomes primarily of the eighteenth century included The English Pilot, A Pilot for the West Indies, American Coast Pilot, and The British Mariner’s Guide. One title became known as the “seaman’s bible.” First published as The New Practical Navigator, it was written by John Hamilton Moore, but Nathaniel Bowditch, who had basically home-schooled himself before putting to sea as a ship’s clerk and later master, discovered errors in Moore’s calculations. For example, the table listed 1800 as a leap year and listed March first with a declination of seven degrees eleven minutes. In actuality the declination was seven degrees thirty-three minutes, which translated into an error of about twenty-three miles. In 1802 the American publisher asked Bowditch to correct the errors and eventually reprinted the book as The New American Practical Navigator. The next edition included corrected charts, instructions on how to navigate, survey direction, collect wind data, and calculate high tides, and information about currents, the ship’s log, marine insurance, bills of exchange, and the responsibilities of the owners, masters, factors, and agents. From then on the book’s author was known as Nathaniel Bowditch. It has been in print for over two centuries.
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PostPosted: Sat Apr 22, 2017 3:28 pm    Post subject: Reply with quote

Telescopes, dividers, parallel rulers, and Gunter’s scales were also essential tools. The first, usually called a spyglass or “bring ‘em near,” was usually made of brass and kept in a mahogany case to protect it from the elements. Recovered from the wreckage of the Whydah were several examples of brass dividers. These were used to measure distance and to plot a course on a sea chart and resembled the compass used in geometry. Archeologists discovered “five pairs of brass navigation dividers in extremely fine condition” from the wreckage of the Speaker, John Bowen’s pirate ship that sank in 1702 off the coast of Mauritius. (X Marks the Spot, 90) Gunter’s scales, also known as “Sliding Gunters,” were a predecessor of the slide rule.





To calculate latitude a variety of instruments were used, depending on the time period. The earliest of these was the astrolabe, which Arabs invented for use on land. This brass ring had degrees marked on it. Two cross pieces intersected each other and formed four small triangles. Attached to the intersection were a knob and two pointed lengths of brass that could be moved to determine the angle of the sun at a certain time of day, or the polestar at night. The astrolabe was in use as early as the second century BCE, but none before the sixth century have survived. Muslim seamen used it in the ninth century, not to determine the ship’s location, but to know where Mecca was so they could pray. European seamen began using it in the eleventh century, and it remained in common use during the fifteenth and sixteenth centuries, after which its use and importance slowly declined. The problem with the astrolabe was it wasn’t accurate; the navigator needed a steady hand and the wind could influence its readings. An error of one degree equated to sixty miles. Often a navigator’s reading was off by four or five degrees, which meant the ship was far off her desired course.



Astrolabe Front


Astrolabe Rear


Astrolabe in Use

A cross-staff was similar to a yardstick with a sliding bar (about two-thirds as long) set at right angles across it. One end of the staff and both ends of the bar contained sights that allowed the user to hold the end of the staff to his eye while adjusting the bar in a vertical position until he saw the horizon through the sight at the lower end of the bar and a star (usually the sun, but he could use the North Star) through the upper end of the bar. As long as he took the sighting in relatively peaceful seas, the navigator could compute their latitude with a fair degree of accuracy.


Cross-Staff in use

These two instruments, however, required the user to stare directly into the sun, which eventually could blind a person. John Davis invented the back staff (also called a quadrant) in 1595 to replace the cross-staff. The back staff looked like a long “Y” with an arced bar having degrees marked on it. A smaller “Y” branch was attached near the base and on the opposite side of the long “Y.” It, too, had an arced bar with angles marked on it. Both arcs possessed vanes. The navigator peered through the sighting vane (on long “Y”), while positioning the shadow vane. At the base of the backstaff was a square with a slit in its center. This was the horizon vane. The navigator faced away from the sun and aligned the backsight (sighting vane) so he could see the horizon vane. Then he moved the peg of the shadow vane until a shadow fell on directly on the slit in the horizon vane. These two angles told him the angle of the sun and the latitude of the ship.

SextantAfter 1759 the sextant slowly replaced the back staff and cross-staff. John Hadley invented its predecessor, the octant, in 1731. Both used mirrors to measure latitude and were more accurate than their predecessors because users could view the horizon and sun at the same time. The sextant resembled an upside down “V” with a graduated arc – known as an index bar – that stretched across the two ends of the “V”. At the point was a movable gear attached via a strip of metal to the index bar. The navigator peered through the lens reflecting the sun, while moving the gear until the mirrors lined up the sun with the horizon. The angle on the index bar allowed him to calculate the sun’s angle and the ship’s latitude.
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PostPosted: Sat Apr 22, 2017 3:29 pm    Post subject: Reply with quote

While there were instruments to determine the ship’s latitude, calculating her longitude remained a major problem. The principal means navigators used to make this determination was dead reckoning, which calculated a ship’s position based on the last fixed or observed position. The sea artist took into consideration the distances entered in the ship’s log, as well as the courses steered and the winds and weather encountered since the voyage began. At best he made a good guess as to where the vessel was, but more times than not his guess was wrong. That error could and did place ships way off course or in serious jeopardy. The Mayflower was supposed to anchor in the Chesapeake Bay, but ended up off the coast of Massachusetts.

To accurately determine longitude, a sea clock was needed, but on a ship the elements affected these instruments. The first such clock wasn’t invented until the 1700s, and not until 1762 and 1764 was one of John Harrison’s inventions proven to accurately work on voyages to the Caribbean. Even so, chronometers (a sea clock lacking a pendulum) were too expensive for most ships and/or seamen to have. The British Royal Navy didn’t issue them to the majority of their vessels until 1825. Greenwich Mean Time, upon which time was standardized, didn’t become effective until 1833.


Notes:

1. The navigator, also known as a sailing master and one of the sea artists found aboard a vessel, was an educated man who knew trigonometry and could determine the best route to get the ship to her destination. The helmsman, on the other hand, was one of the crew – each seaman took his turn at the whipstaff or wheel. He used a compass and the sun, moon, and stars to follow the course the navigator determined.

2. While Dampier never referred to himself as a pirate, or his participation in raids against the Spanish as piracy, his buccaneering “adventures” took him to places little explored by Europeans. He made meticulous notes not only of the flora, fauna, and people, but also “the movements of the tides, currents, and winds around the islands.” (Preston, 1) On his three voyages around the world, he took precise measurement of distances and “pinpointed the location of islands, while giving practical tips on the best approaches through reefs, tidal races, and shoals.” (Preston, 6) The Royal Navy would still rely on this information three centuries later.

3. The measurement refers to the rope’s circumference, rather than its length.

4. One measurement frequently given with a ship is her draft/draught. This is how much water she requires to stay afloat. If her draft is seven feet, she needs more than seven feet to remain movable in the water. If the water is six feet deep, she’s either wrecked or aground.
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Captain Teague
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PostPosted: Tue May 16, 2017 1:42 am    Post subject: Reply with quote

Interesting information.
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