Sailing also spurred the development of mathematics, astronomy and timekeeping. To sail anywhere on the globe and return in a predictable fashion requires celestial navigation. Celestial navigation is dependent on five instruments: a sextant, a chronometer, an almanac, a sight reduction table and a position chart. These were necessary in order to determine two things--latitude and longitude. Where these two lines intersect on the globe is where your ship is. That’s a lot harder than it might sound. To determine longitude, ships used a chronometer (actually three). These were extremely accurate clocks. Prior to 1761, European clocks were pendulum-driven. This was no use to sailors due to the rolling and pitching of ship. So, before 1761, sailors determined longitude quite accurately using lunar distances. The navigator measures the angle between the sun and moon or between the moon and certain stars (called navigational stars of which there are 57) along the ecliptic plane (the sun’s apparent path through the sky). The measurements must be precise. Having obtained the angle, the navigator consults an almanac that gives the angles of these various celestial bodies relative to the center of the earth and then correlates that to Greenwich time. Knowing what the time is in Greenwich, enables the navigator to know how far away from Greenwich the ship is which is plotted on a chart as the longitude. This method works quite well except there is one obvious and highly dangerous problem for a ship far out at sea: what if the weather is overcast for days at a time? To go four days without being able to plot a position is far too risky to chance.
http://www.youtube.com/watch?v=rVQXhooBux4
So an accurate, non-pendulum-driven clock had to be developed so that the Greenwich time could be determined without being dependent on celestial measurements (or “sights” as they were called). John Harrison spent 31 years building such a clock and finally succeeded in 1761. It was essentially a highly accurate watch mounted on gimbals in a box to hold it steady. Most ships used three chronometers so that they could be checked against one another. If one chronometer started to drift, the other two would inform on it. These chronometers had to be wound at regular intervals and this duty was all-important and took precedent over any other duty. The captain and navigator (virtually always the first mate) usually had the keys to wind the chronometers. Failure to wind them was considered criminal placing the entire crew at jeopardy. The chronometers were mounted firmly to the ship itself so that they could not be tossed about by sea turbulence and they were highly resistant to angle, pressure and temperature changes. The navigator carried a very accurate pocket watch on his person that was calibrated to the chronometers and he would use this watch to mark the time when he went topside to take his sights. That way, the chronometers were never exposed to the elements outside the ship. Sailing gave us precision machinery tried and tested under the harshest of circumstances.
To measure latitude, the navigator used a sextant, so named because of it is 1/6th of a full circle, i.e. a 60-degree frame. The sextant has two mirrors on it. When the navigator looks the telescope viewer, he is looking through a mirrored but transparent surface called a horizon mirror. He looks that the horizon in the telescope and can see it through the horizon mirror. Then he uses the movable arm of the sextant to locate the sun or moon (or some designated planet or star). There is an index mirror mounted on the arm at the top of the sextant. When the desired celestial body is caught in the mirror, its reflection is bounced to the horizon mirror. The navigator can now see the body and the horizon simultaneously and lines them up inside the telescope so that the body appears just above the horizon in the horizon mirror. This accomplished, he reads the angle off the frame and notes the time. The advantage of two mirrors is that relative motion of the instrument is eliminated so that the view in the telescope is steady. The navigator obtains his angles and consults his almanac to find out the latitude or he can simply read Polaris from the horizon. However many degrees Polaris is above the horizon is also the latitude because it is situated almost directly over the North Celestial Pole. The problem, of course is that this method does not work below the equator since Polaris will not be visible.
Another way to use the sextant to determine latitude is to track a celestial body as it rises. If it tracks to the south as it rises then one is above the equator. If it tracks to the north then one is below the equator. If the body rises straight up then one is on the equator. The amount of this northerly or southerly tracking increases the farther one is away from the equator. So, again, consulting an almanac will then reveal the latitude.
This information was plotted on a position chart to pinpoint the ship’s location. Using wind speed, wind direction and compass, one could predict the time of arrival at their destination and the sails were then set accordingly. This too was a specialized task. Sailing a ship far out at sea was no easy task. People had to know what they were doing or they had no chance to ever come home.
That’s one reason that punishments of sailors was so harsh. The hands had to do exactly as they were told or everyone onboard was put at risk. This was a true of officers as the regular men. Anyone who failed to perform his duties in a timely fashion was punished in a timely fashion. Punishments ranged from flogging to yard-arming to gagging to keelhauling. The last was the worst because the victim rarely if ever survived it. The victim was tied around the hands and feet and dragged across the bottom of the ship against the barnacles across the keel to the other side and back again from fore to aft. This was reserved generally for captured pirates. Gagging was done to sailors who talked back. Not too severe but definitely painful and had the effect of tightening up wagging tongues. Yard-arming was hanging a sailor from the yard-arm either by the wrists or with the rope tied around the waist to swing in the breeze for a good four hours while the rope cut into the flesh. Flogging was done by the master-at-arms and a special station was reserved where it took place. All hands not on watch were required to attend in order to send a message. Depending on the captain and other officers, punishments could be rare and only for significant offenses or could be frequent and applied with very little provocation. Most ships were somewhere in the middle. Punishments were most frequent and most severe in the Navy.
Many sailors were young men from the streets. They were tough and often brutal themselves. Many, especially in England, were pressed into service and were not exactly willing participants in the shipboard life and adventures and so needed a bit of motivating. Punishments as extra duty or fining was simply not going to have much effect on the men’s behavior. The punishments had to be harsh so that they would be remembered. Unfortunately, these punishments were frequently doled out to men who had done little to deserve it.
A boy to me was bound an apprentice
Because his parents they were poor
So I took him from St. James’s workhouse
All for to sail on the Greenland shore
One day this poor boy he did annoy me
Nothing to him then did I say
But I rushed him to my frozen yard-arm
And I kept him there ‘til the very next day
When his eyes and his teeth did hangs towards me
With his hands and his feet bowed down like ice
And with a bloody iron bar I killed him
Because I would not hear his cries.
But sometimes there could even be worse things than punishment. Melville recalled one first mate on a ship he served on who had the hardest, meanest, coldest, most piercing eyes he had ever seen. Whenever he looked at you, your blood ran cold. If he came upon you standing around not doing anything, instead of threatening you with punishment, he would just fix those eyes on you which was so intolerable that you would immediately grab any tool near you—mop, marlinspike, hammer, harpoon, rope, paintbrush—didn’t matter—and just start doing something with it—anything—“anything to get those damned eyes off you.”
In another case, an 18th century British Navy captain known for his meanness came upon deck and saw men up in the rigging repairing sails, painting and what not. He yelled for all of them to come down this instant—last one down gets 50 lashes. None of the hands doubted him and they began clambering down as fast as they could go. Two men lost their grip, fell to the deck and died on impact. The captain chuckled and said with a sadistic grin, “Throw the lubbers overboard!” and then simply walked away.
http://www.youtube.com/watch?v=mOj3kJKy-_U