Navigation of the American Explorers - 15th to 17th Centuries
Seventeenth century travelers to Maine’s coast such as Samuel ChamplainChamplain, Samuel de Samuel de Champlain
1567-1635. Between 1603 and 1635, Champlain made 12 voyages to what was to become Canada, establishing it as a French colony, founding Quebec, and exploring up the St. Lawrence River to the Great Lakes.
Read More, George WaymouthWaymouth, George George Waymouth
c.1585-c.1612. English ship captain and explorer, and student of mathematics, navigation and ship building. In 1602 he led an unsuccessful voyage in search of the Northwest Passage, exploring the area between Greenland and Labrador. After returning he wrote "The Jewell of Artes" a manuscript on navigation, shipbuilding and fortification presented to King James I.
Read More, and John SmithSmith, Capt. John Captain John Smith
c.1580-1631. English soldier, sailor, and writer, who became the leader of the Jamestown Colony. Chiefly known in New England for his 1614 voyage in which he mapped much of the coast.
Read More carried state-of-the-art navigation tools for both dead reckoningDead reckoning
Navigating by applying courses and distances made through the water from the last known observed position. The term dead could be a form of "ded" from "deduced" reckoning. and celestial navigationCelestial navigation
Using the sun, moon, stars, and planets to find your location..
Navigation Tools for Dead Reckoning and Piloting
Invented in China in the 3rd century BC, the compassCompass
Instrument which indicates true or magnetic north, enabling the mariner to guide a ship in any direction and to determine the direction of a visible object, such as another ship, heavenly body, or point of land.
Read More did not come to Europe until the 12th century AD. By the time of Columbus'Columbus, Christopher Christopher Columbus
1451-1506. Italian explorer and navigator. After finding Spanish backing for his plan to find a short way to the Orient, he sailed in 1492 and landed in the Bahamas, then explored a portion of the Caribbean before returning.
Read More voyage it was common. Instead of degrees, the compass cardCompass card
Magnetic marine compasses have the magnets fastened to a circular card which has the directions on it. Traditionally compasses were marked in points of 11 1/4 at every 11 1/4 degrees. The whole card rotates and a mark on the compass housing called a lubber line indicates direction.
Read More, on which directions were drawn or printed, showed the points of the compass, including north, south, east, and west. There are 32 points of the compass, the four main quadrantsQuadrant
An astronomical instrument for measuring angles with a quarter circle graduated arc. The seaman's quadrant, or simple quadrant, was the earliest instrument used by navigators for measuring the altitude of a heavenly body. Other instruments not strictly quadrants have also been called such. The backstaff may be called Davis Quadrant. The octant was originally called Hadley's quadrant. of the circle each divided into eight 11¼ ° points. Columbus noticed that, as one sailed across the Atlantic Ocean, the variationMagnetic North and Variation
Magnetic north is one of two points on the globe where the line of total magnetic force is vertical and towards which the magnetic needle points in all adjoining regions. Variation (also called magnetic declination) is the difference in direction between true north as determined by the earth's axis of rotation and magnetic north as determined by the earth's magnetism.
Read More between magnetic north and true northTrue North
The direction of the North Pole from any place on the earth's surface, through which all meridians of longitude pass on maps and charts.
Read More changed. On future trips he used this to predict, roughly, his arrival in America.
The next most important tool was the chip logChip log
Device used in the past on sailing vessels for measuring the rate of speed of the vessel. A quarter circle quadrant of wood, or "chip," fastened to a line, was allowed to run out over the stern, and the amount of line run was measured in time with a half minute sand glass. The sand glass replaced counting the seconds.
Read More, introduced in the late 16th century to measure speed. The chip, a quarter circle of wood, was attached to a light line on a reel. Knots were tied at 47' 3" intervals, the distance the line would be pulled out in 28 seconds if the ship’s speed was one knotKnot
A nautical measure of speed. One knot is equal to one nautical mile (6,080 feet) per hour. The term comes from the knots on the line of a chip log. or nautical mileNautical Mile
One minute (or 1/60th of a degree) of latitude. Because the earth is not a perfect sphere, the length of a nautical mile varies somewhat according to latitude.
Read More in an hour, when the chip was dropped overboard. With a 14- or 28-second sand glassSand glass sandglass
A means of measuring time on board ship before the development of reliable clocks for ships. Two vacuum globes connected by a narrow neck, allowing sand to run from the top globe into the bottom one in a given period of time.
Read More, navigators could see how fast the vessel was going by counting how many knots rolled out before the sandglass expired. Before the chip log, navigators estimated speed by timing how long a chip of wood in the water would take to pass from bow to stern.
Compass and log helped navigators keep track of position. They used a lead lineLead line
A means of finding the depth of water near coasts and probably the earliest device used by coastal navigators to facilitate safe navigation. It consists of a hemp line with a lead weight attached (about 7 pounds).
Read More to determine water depth and bottom type. A heavy piece of lead at the end of a long marked line had a cavity in its bottom, which, when coated with grease or tallow, brought up a bottom sample. Experienced navigators often could determine position based on whether the bottom was muddy, sandy, pebbly, rocky, or covered with vegetation or shell fragments. Crossing the Atlantic, navigators used the lead line to find the continental shelf, and, more importantly, find the Grand BanksGrand Banks
A large shallow area, rich in fish, located in the North Atlantic off Newfoundland.
Read More and other fishing grounds.
To record a vessel’s courses and speeds, the navigator used a traverse boardTraverse Board
The traverse board is used to keep track of changes in a vessel's speed or course over the course of a four-hour watch.
Read More. The board had a line of holes radiating from the center towards each of the 32 compass points. Sailors inserted pegs in the holes to show the vessel’s course and speed each half hour. The navigator then used traverse tables to add these and give an average course for a four hour watch. This result then was entered into a logbook along with information about the weather, changes in sails, and items concerning the crew.
Guides for the Navigator
The seventeenth century navigator had little published information. ChartsChart
A nautical map giving navigation information, including: water depth; shoals, rocks, and other dangers; and aids to navigation such as lighthouses, buoys, and beacons. Charts use special symbols and abbreviations to convey information for mariners. were rare; some advanced navigators carried globes. MercatorMercator, Gerardus Gerardus Mercator
1512-1594. Flemish mathematician and geographer who, after moving to Germany in 1552, invented the map projection named after him. His world map was first published in 1569. projection charts were far more useful than earlier charts. With its mathematical errors corrected by Edward WrightWright, Edward Edward Wright
1561-1615. English mathematician and cartographer. Edward Wright's world map of 1599, published in 1600, coupled with his 1599 book "Certaine Errors in Navigation" corrected errors in Mercator's projections so that rhumb lines appear as straight lines.
Read More in 1599, the Mercator projection chart allowed mariners to draw a rhumb lineRhumb line
Straight line compass course between two points on a Mercator chart. Formally a line of constant bearing that crosses all meridians at the same angle which displays as a straight line on a Mercator chart but as a spiral on a globe. This sprial line is called a loxodrome. between two points, get a bearing and sail that line.
The earliest sailing directionsSailing directions
Originally called "routiers" or "rutters", written directions for navigation. originated in the Mediterranean as manuscripts called portolanosPortolano
Italian manuscript sailing directions used in the Mediterranean between the 12th and 15th centuries. Contemporary with and backed up the portolan charts of the areas, hand drawn charts with compass or direction lines. which were first printed in the second half of the sixteenth century. The first important collection was published in 1584 by the Dutch pilot WaghenaerWaghenaer, Lucas Janszoon Lucas Janszoon Waghenaer
c.1534-1606. Dutch pilot and cartographer. Based on 25 years of experience as a pilot and opportunities to examine numerous rutters and manuscript charts he was able to compile the first effective set of navigational charts published 1584-85 under the title Spiegel der Zeevaerdt or Mirror of the Sea.
Read More. These volumes, with charts, sailing directions, navigational instructions, and tables, became known in England as "Waggoners"Waggoner
Waggoner, generic 17th century and early 18th century term for sea charts derived from the first publisher's name Waghenaer. In 1671, the first of four volumes of The English PilotThe English Pilot
English sea atlas published from 1671 to 1803, initially by John Seller who was appointed Royal Hydrographer in 1671. These were intended as working charts. The Fourth Book, first issued in 1689 covered North America and Canada. appeared, based mostly on Dutch sources. These covered Europe, the Far East, and North America.
Tools for Finding Latitude and Time
The only way navigators could estimate a vessel’s longitudeLongitude
Longitude lines around the globe run north-south, and measure position east or west of a reference line.
Read More was by dead reckoning and measuring variation. Celestial navigational instruments were designed to help find a vessel’s latitudeLatitude
Latitude is the measure of how far north or south one is from the equator. This angular measurement is given in degrees, minutes (1/60th of a degree), and seconds (1/60th of a minute) of arc.
Read More, the approximate time, and the direction of true southTrue South
The direction of the South Pole from any place on the earth's surface, through which all meridians of longitude pass on maps and charts. It is the direction that the sun is from the observer at local noon or when the sun is highest in the sky..
The quadrant, the earliest device used to find latitude, was a quarter-circle of wood, marked in degrees, with a plumb line and a sight along one edge, first taken to sea around 1460. Another early latitude-measuring device is the astrolabeAstrolabe
The seaman's astrolabe is a graduated ring or disc fitted with a sighting rule pivoted at the center.
Read More. It is a disc with degrees and a movable arm with sights, first known to be at sea about 1481.
In the 15th century, Portuguese Prince Henry the NavigatorHenry the Navigator
1394-1460. Henry, Prince of Portugal, took the name Navigator because of his patronage of a succession of Portuguese seafarers who explored the Atlantic islands off Portugal and down the African coast, ultimately rounding the Cape of Good Hope.
Read More pioneered nationally sponsored exploration and cartography. Portuguese navigators apparently took the cross staffCross staff cross-staff
Early navigational device for measuring altitudes of heavenly bodies, also called a fore-staff, based on an Arab instrument called a Kamel.
Read More to sea about 1515. It has two parts: a long graduated staff and a sliding crosspiece.
The navigator holds one end of the staff near his eye, where both the sun and horizon may be sighted, and then moves the crosspiece along the staff until one end is lined up with the horizon and the other with the sun or star. The angle is read from the scale on the staff. The cross staff required the navigator to look directly into the sun, almost impossible in bright sunlight. But it could be used when the ship was moving, and it was simple and relatively inexpensive.
A variation of the cross staff is the backstaffBackstaff back staff, back-staff, Davis quadrant
A navigational instrument for measuring the altitude of the sun, introduced in the 16th century.
Read More, invented by John DavisDavis, John John Davis
c.1550-1605. English navigator and explorer. In 1585, started his first expedition to search for a Northwest Passage around the top of North America to the Orient.
Read More about 1594 and published in his Seaman’s Secrets in 1595. With it a navigator could measure angles accurately without looking directly at the sun.
The backstaff, in its final form, was made of wood and was made up of two arcs, a larger 30° arc and a smaller 60° arc. VanesVane
1. Rotating device which is used to indicate direction of wind. Also called wind or weather vanes.
Read More allowed accurate sighting of the horizon, while the sun showed a shadow on another vane. Also called a Davis quadrant, it could only be used for sun sightsSun sights
Altitude observations of the Sun needed for celestial navigation. "Sights" generally refers to taking a sun sight, but means also taking star sights at night..
At night, navigators could tell time using a nocturnalNocturnal
An early instrument designed for measuring time of night by means of Polaris (the Pole Star) and other points in constellations., a device that measured the angle from the North Star to the pointer stars, either in Ursa Major (the Big Dipper or Big Bear) or in Ursa Minor (the Little Dipper or the Little Bear). It used the vertical as a reference, and required the month and date to be set. A sundialSundial
A device that measures time by the position of the sun. Known from Ancient Egypt. For navigation special ones were developed that could tell local noon on board ship. could be used in daylight.
By the middle of the 17th century, thanks to the invention of logarithms by John NapierNapier, John John Napier
1550-1617. Scottish mathematician and scholar, best known for his invention of logarithms and a calculator based on these. Napier's logarithms simplified calculations making trigonometric calculations possible for those with little mathematical training. Kepler used them in his orbital calculations. which were transformed into a simple calculator by Edmund GunterGunter, Edmund Edmund Gunter
1581-1626. English mathematician who published trigonometric tables in 1620 with logarithms.
Read More, navigators with little mathematical training could solve trigonometric navigational problems.
By the end of the seventeenth century, navigators were able to tell time within a quarter of an hour and find their latitude within a few miles. Despite their relatively simple instruments, these mariners sailed the globe.