Thursday, October 29, 2015

Breakwater of Khor Rori

One of the more important aspects of Khor Rori that is overlooked by nearly all theorists, is the problem facing a vessel moving out of a harbor, inlet, or narrow opening into the sea with conflicting tides, currents, winds, and sea depth.
These three images show the problem with moving from a protected harbor out into the sea. Top: What appears to be a smooth flow of water outward, is (Middle) at least a rough and confusing tidal and current movement that makes for breaching the ocean a very difficult thing, and (Bottom) at times can be quite dangerous
    The concept of bottom topography plays an important role in a vessel breaching the ocean from an inlet, river, or harbor where a channel exists. That is, for the ship to have been built, it would have needed some type of harbor where the entrance to the sea was narrow enough to restrict tidal and current fluctuations where the boat was moored. The problem lies in that vessel then leaving the inlet and entering the sea. As Nephi states it: “And it came to pass after we had all gone down into the ship, and had taken with us our provisions and things which had been commanded us, we did put forth into the sea and were driven forth before the wind towards the promised land” (1 Nephi 18:8).
The problem any vessel has in leaving protected harbor or inlet is to breach the current and waves upon entering the sea. Even modern-day diesel driven vessels have problems. In the days of Lehi, hitting swells like that could cause a broach, turning the vessel sideways to the swell and even capsizing
    In order to “put forth into the sea,” the ship would have to move out of the protected harbor, over the uneven topography that always lines areas where inlets, rivers, khors, etc., empty into the sea.
    First of all, probably one of the least understood and anticipated influences on wave conditions is bottom topography. Water depth has a major effect on waves, which will behave very differently between shallow and deep water.
    Waves do not merely affect the surface of a body of water. The motion involved actually goes down fairly deep, around four times the height of the waves. So if a wave is four foot, the water is being disturbed down to a depth of about sixteen feet.
    Thus, where the bottom suddenly rises up to near the surface, such as the mouth of such an inlet, this can cause nasty sea conditions—it is somewhat like wind flowing around tall buildings, and water moving against a submerged plateau is going to "hump up" at that point. And that “hump” causes a giant lift in the prow of the vessel and with an inexperienced crew, could cause serious damage.
    Not only does the underwater obstruction force a change in water flow direction, but will cause increases in velocity and create nasty eddies, which can create some of the most dangerous water conditions there are—like rapids on a river that only a very skilled boatman can handle them. Such places can be serenely placid at one moment, and deadly the next as the slack tide or winds suddenly change. Consequently, sailing from any location of a protected harbor or inlet out into the sea would present problems for an inexperienced crew like that on Nephi’s ship.
What has been done in modern times, though not always understood anciently, is the building of a breakwater system at such a harbor in inlet area, to reduce the intensity of wave action in inshore waters and thereby reduce the difficulty of entering the sea, though today, with diesel engines, that is not the problem it once was. In fact, breakwater systems are generally meant to break the force of waves, to an inlet, river entrance, or harbor as well as to protect anchorage within the inlet or harbor.  
Waves roll in series, and every so often, a rogue or unusual wave will occur, at first hidden among the swells and undistinguished to those who do not know what to look for
    It should be kept in mind that waves have a life cycle of their own. As an example, with every 30th to 40th wave comes a wave that is much larger than all the waves before it. Basically the set of 4 waves merge and create a super wave. Recent studies have shown that these rogue waves may be more common than oceanographers first thought, and they are unpredictable, usually out to sea, but also along the coast and can create undue damage. Even smaller forces can disrupt steerage, especially at critical times such as moving out to sea, with the deeper the water, the greater the change at such disruption.
    One of the important things to keep in mind about the Sea of Arabia along the south Arabian coast is that the sea has depths that exceed 9,800 feet, and there are no islands in the middle. Deep water reaches close to the bordering lands except in the northeast, off Pakistan and India. To the southeast the Lakshadweep atolls along the southwestern coast of India, form part of the submarine Maldive Ridge (1800 miles off Arabian coast), which extends farther south into the Indian Ocean where it rises above the surface to form the atolls of the Maldives. On the western side of the sea, 300 miles south off the Omani coast, the plateau island of Socotra, about 70 miles long and with an area of about 1,400 square miles, is an insular extension of the Horn of Africa, lying 160 miles east of Cape Gwardafuy (Guardafui).
    All of this leads to the point that in this huge box-like area off the coast of Khor Rori is a very deep sea of approximately 10,000 feet depth, where water is moving inland toward the coast. When it reaches the area of rising land, it creates undertoes, cross-currents, rising tides and tidal influences as well as other navigational problems for a vessel entering the Sea of Arabia from an inland khor or river.
    In a wooden sailing ship of 600 B.C., the results of an inexperienced crew in such waters would be disastrous.
    However, one of the interesting factors of Khor Rori is the natural breakwater effect provided by the two promontories along the entrance to the inlet on either side of the khor. These two promontories or cliffs stand about 100 feet high, blocking any winds that would effect the sails of the ship as it passed, in addition, the extensions of them also block current eddies and tidal changes along the coast, providing a “breakwater” arrangement out three hundred to four hundred feet, more than three times the length of the boat and, therefore, providing a smooth transition between khor and sea.
Yellow Arrows: The Inqita’at Mirbat and Inqita’at Taqah promontories on either side of the Khor Rori inlet mouth, provide a form of breakwater and (Blue Arrow) a safe and easy entrance into the Ocean from the river (khor)
    No other area along the coast provides such an easy egress into the sea and is one of the major reasons the area was used by Roman ships and traders for several centuries  from around 200 B.C. onward.
These 100-feet tall cliffs on either side of the entrance to the inlet act as breakwater barriers and bring a tranquility to the waters entering and leaving the khor
    It is interesting that these promontories provide a dissipation of energy and relative calm water created in the lee of the breakwaters, thus allowing a vessel of Nephi’s size to pass between and out into the ocean along a protected path, requiring very little expertise from the crew.

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