Chapter 738： Upper edge slant sail and fin stabilizers (lower)

The upper edge truss sail is the highest technical achievement of sail power, but it is a bit out of date. When the upper-edge slanted sail developed to its peak, the time was already in the late 19th and early 20th centuries.

By this time, the steam engine technology had already matured, and even steam turbines appeared. In the early 20th century, the upper edge slant sail was mainly applied to flying shears. After all, the sail power does not need to carry coal, how economical it is, and it can also save space for cargo transportation. In addition, the speed of the flying shear ship was not slower than the ordinary steam engine merchant ship in the early 20th century ...

However, the subsequent series of accidents cast a shadow on the sailing boat. Coupled with the advent of more advanced and efficient diesel engines, the flying shear boat driven by the upper edge slant sail has finally withdrawn from the stage of history.

So, what kind of accident is it? It turned out that ten 6-mast and over 6-mast Skuna sailboats (flying shear boats using upper-edge slant sails) were built in the early 20th century, including several of the unlucky "Wyoming" previously mentioned. 10,000-ton flying shear ship ...

Then, people were cherished by this high accident rate, and finally abandoned the flying shear ship using the upper edge slant sail. But Marin has read history and knows that it really can't blame the upper edge truss sails. Rather, the multi-mast upper-edge slant sail and flying shears do not match ...

Why do you say that? Because Marin believes that the flying shears are too "thin". Its length-to-width ratio of 6 to 1 or even higher makes the hull of the flying shears extremely “weak”. The danger of a boat that is too thin is that it can easily roll over.

The upper edge truss sail is a longitudinal sail, and most of the borrowed is the side wind. But the wind coming from the side, while pushing the ship forward, will also push the sailboat to the side at the same time ...

If the wind is small, it ’s okay, but if you encounter a big storm, a “thin” flying shear ship with up to six upper-edge slanted sails will naturally roll over easily ...

What's more, this Skuna six-masted flying shear is unlucky. Why? Because shortly after they exited the stage of history, a technology called "fin stabilizer" appeared and was put into use ...

What is fin stabilizer? It is to install artificial "shark fin" in the underwater part of the hull, so that the hull can ensure a better balance. Modern warships are actually as thin as flying shears, and even more so. For example, the "052D" destroyer has a length of 157 meters and a width of 19 meters and a length-to-width ratio of up to 26. It is also twice as fast as a flying shear. But why don't modern warships overturn their ships? Because they are all equipped with "artificial shark fins"-fin stabilizers. Moreover, not just one pair, but many pairs ...

In this way, even if the speed is up to more than 30 knots, the modern battleship is still as stable as the old driver ...

The six-masted flying shears had withdrawn from the historical stage before the fin stabilizer technology was mature and put into application, so it is a pity. If you install a few pairs of "shark fins", you won't get 10 sinking several ...

Moreover, the upper edge skewer sails were not eliminated, but continued to be retained by modern sailing ships. However, modern sailing ships are mostly small sailing ships, single-masted, mainly used for sailing. The modern sailing ships that Marin had seen in the previous life basically used upper-edge slanted sails, and then placed a soft sail on the front to take advantage of the wind ...

...

So, how did the upper edge truss sail come from? Marin read the history of navigation in his previous life. That is how it was introduced above ...

The book says that in the 17th and 18th centuries, it was extremely inconvenient to operate because the Latin spinnaker changed direction. In order to facilitate the rotation of the sail truss, people directly truncated the front half of the oblique Latin sail's diagonal truss (that is, the lower edge diagonal truss).

However, in this way, the Latin spinnaker lost half of the truss, the area of ​​the spinnaker was also reduced by half, and the ability to use wind was greatly reduced.

So, people began to think of a way, at the mast, got a wind rod that can rotate around the mast. The wind control rod is perpendicular to the mast, and a metal collar is connected to the bottom of the mast. In this way, the sailor can pull the wind lever directly in the horizontal direction by hand or rope.

The remaining upper edge girders are also connected to the mast with a metal collar. However, unlike the wind control rod, the wind control rod is perpendicular to the mast, and there is an angle between the upper edge diagonal truss and the mast. The angle is still the same as before when the lower edge diagonal truss is retained. , Also known as the upper edge girders.

As for the sail, it is pulled between the bottom sail rod and the upper upper edge girders. In this way, the shape of the sail surface becomes a rectangle with a right triangle on top. The area of ​​a square with the same height and width is twice that of a triangle. Therefore, the area of ​​this new type of upper-edge girdle sail is not smaller than that of the Latin sail when the lower-edge girder is retained. What's more, on the upper edge of the diagonal girders, you can also add a right-angled triangle jib to further increase the sail area and strengthen the wind capacity.

Moreover, the manipulation of sails is extremely simple. When the wind changes, the sailor only needs to rely on the winch rope to control the direction of the lower windsurfing rod on the upper edge slant sail, and let it turn around the mast to the opposite direction. Even, one or two sailors can easily get the reversal of the upper slant sail, and the time is very short.

Unlike a sailing boat, because the sail is lowered from the upper truss, every time the boat is sailed, the sailor needs to climb up to a tens of meters high to put the sail down and tie it firmly. It is also very troublesome to close the sails. Sailors need to climb up to a tens of meters high mast, first untie the lower end of the bound horizontal sail, then pull it up, and put it on the upper boom ...

Such an operation is nothing when it is calm. But if it suddenly encounters a storm, it will be miserable.

Because storms at sea often carry heavy rain. If the sails are not collected quickly, the ship may be overturned by a severe storm. However, the closing of the sail requires the sailor to climb up to unlock the lower end of the sail and then pull it up. It's okay to climb the mast at ordinary times. Climbing the mast during storms is very dangerous. Because the rain-stained mast is relatively slippery. If you accidentally fell from a mast tens of meters high, you might die on the spot ...

Therefore, in the era of great navigation, there are many sailors who fall off the mast and die every year ...

The upper edge truss sails are different, because the upper edge truss sails, like Chinese hard sails, rise from below, just like raising the national flag. When it encounters a storm, just untie the rope under the mast and lower the upper edge slant sail. Even the upper edge girders can be lowered together ...

The upper edge slant sail is generally connected to the bottom of the sail rod (can also be removed), and the end of the edge close to the mast is connected to the mast through many copper rings that surround the mast.

When raising the sail, the sailor pulled up the top edge of the slant sail by pulling the pulley. First, the top of the jib above the upper edge girders. After the upper jib is straightened, the upper edge girders that surround the mast through the metal ring are driven to rise together until the upper edge girders reach the top, and the bottom The main sail is pulled straight up (generally it will not be stretched too tightly, because you have to go for a ride). Then, tie the rope, fix it, start turning the wind lever, and adjust the direction according to the wind direction ...

what? You said how to keep the wind rod and upper edge diagonal beam on the same plane? This is very simple-just make a vertical guide on the wind lever. In addition to using a metal ring to surround the mast, the upper edge diagonal truss also needs to cover this guide rail parallel to the mast ... In this way, it can fully ensure that the driving rod and the upper edge diagonal truss are on the same plane. Moreover, it does not affect the rise and fall of the upper edge girders ...

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Fearing that the ship would run aground or hit the reef in the Strait of Magellan, Marin decided to promote this advanced and easy-to-operate upper-edge girder sail to Aben ’s fleet ~ www.novelhall.com ~ As for the use of multiple upper-edge slopes For the wreck of the flying shear ship of the truss sail, Marin felt that as long as he didn't die, he could install multiple upper-edge slant sails on the very "thin" flying shear ship ...

Moreover, there is currently no "thin" flying shears in Marin's hands. There should be no danger in using upper-edge slanted sails on a boat with a length-to-width ratio equal to or lower than 4 to 1 and using no more than 3 masts.

What's more, even if the presence of the upper edge slant sail affects the lateral stability of the ship, that's okay. At most, install a pair of simple fin stabilizers under the hull ... Marin knows it, encyclopedia of the last life As mentioned above-a ship with a displacement of less than 1000 tons, it is enough to install a pair of fin stabilizers ......

However, the ships currently in the hands of Marin simply do not have a displacement of more than 1,000 tons, or even 500 tons. Therefore, when installing fin stabilizers, there is no need to install any modern fin stabilizers that conform to the hydrodynamics. It is enough to simply install a pair of symmetrical common fin stabilizers on both sides.

Moreover, Marin felt that as long as she did not engage in flying shears with upper-edge slant sails, she might not need fin stabilizers. After all, fin stabilizers are used to balance ships with fast speeds. The existing ships in Marin's hands are not fast, and are relatively wide, and they do not need fin stabilizers at all ...