Thursday, March 23, 2017

Understanding Laman and Lemuel and Building the Ship – Part I

Nephi’s comment is quite poignant when he wrote: “And when my brethren saw that I was about to build a ship, they began to murmur against me, saying: Our brother is a fool, for he thinketh that he can build a ship; yea, and he also thinketh that he can cross these great waters. And thus my brethren did complain against me, and were desirous that they might not labor, for they did not believe that I could build a ship; neither would they believe that I was instructed of the Lord” (1 Nephi 17:17-18).
They said, in effect: “There is no way our younger brother can build a ship! Who does he think he is? And claiming God told him  how to do it! What hutspâ!”
    If you placed yourself in Laman and Lemuel’s position, having spent their entire lifetime of 25 to 30 years living on land and never even been to the seashore, and likely never even saw a small sailing vessel until their journey down along the Red Sea, you can understand a little about their trepidation of working on the building of a ship they knew nothing about and knowing they were going to have to sail out into that vast watery ocean before them their father called “Many Waters.” How on earth, they must have thought, could tons of wood float? They also must have thought they were going to die at the end of their labor by getting on board a hunk of wood tonnage that they could not possibly think Nephi could construct that would support them crossing that sea.
    To us, while we may not understand the principles, we can see a hundred thousand tons of steel floating in a modern aircraft carrier and know it can be done. But to Laman and Lemuel, the vast size of Nephi’s ship as it took shape must have been extremely daunting. These were simple men, who spent their time in the fields of their father’s farm outside Jerusalem, planting, growing, harvesting, and doing minor repairs. Building a ship large enough to carry both families and their households across the great seas would have indeed tried the spirits of the bravest of men.
    While one does not have to be a marine scientist or engineer to understand the scriptural record of Nephi building his ship, it might help in understanding the task that was before them, for ship design and construction would have been as foreign to these individuals as it would be to most of us today—even more for they did not grow up knowing about large ships crossing the seas. To Laman and Lemuel, and the sons of Ishmael, this had never before taken place.
    First of all, those of us who have been in modern sailing vessels with smooth, one-piece fiberglass bodies that slip through the water with east, our appreciation of building one’s own ship with rudimentary tools and absolutely no knowledge would have seemed beyond the pale.
First of all, how was the ship to be designed? What materials would be required and how were they to be shaped and formed? All of them would have been familiar enough with simple building to know that working with wood requires patience and knowledge, expertise and experience. Nephi and the others had none of this other than in the simplest of workings on the farm.
They probably would not have known of the force waves exert on construction in the deep sea, but might have sensed it. An ocean to those who have never grown up around one can seem both menacing and terrifying. Having grown up in Southern California along the seashore, and having numerous family and friends come to town to visit from the Midwest, it was always interesting to see how both impressive and overwhelming the ocean first appeared to them—nor did many want to even go wading in it.
    While Nephi and his brothers might not have known or understood that waves create buoyancy stresses on the structure of a ship’s hull, or that the weight of breaking waves on the fabric of the ship and create damage over time on both the hull and structure as well as the rigging.
    Of course, the Lord did, and it was to be his design and construction methods that Nephi followed. The young man was likely taught in the process that the force of the wind pushes ships in the direction the wind is blowing, literally pushing the vessel forward, thus he stated:"We were driven forth before the wind" (1 Nephi 18:8,9). Ships with large windage suffer most—that is, blowing wind produces a force on the vessel’ structure, called windage, and the area and shape of the ship make it susceptible to friction on those parts of a boat that are exposed to the wind. Although today powered ships are able to resist the force of the wind, sailing vessels, especially in Nephi’s day, had few defenses against strong winds. Thus, the design had to compensate for this, as well as meet certain requirements to keep it afloat. After all, you can’t just build a ship any way you want and expect it to have the required buoyancy to float.
    While the average person would not necessarily know, the Lord of course knew that it is poor design that results in many sinkings, especially in early ships where the instability caused by the center of mass (center of gravity) of the ship rising above the metacenter resulting in the ship tipping on its side or capsizing (foundered or foundering). As an example, when a ship heels (rolls to the side from a turn, wind or pressure), the center of buoyancy (upthrust) of the ship moves laterally. It might also move up or down with respect to the water line. The point at which a vertical line through the heeled center of buoyancy crosses the line through the original, vertical center of buoyancy is the metacenter, which remains directly above the center of buoyancy by definition.
The weight of the ship in the water creates pressure below the vessel, causing the ship to float on a shelf of higher pressure, resulting in buoyancy that keeps the ship above the water line

    This buoyancy or upthrust, is an upward force exerted by the sea that opposes the weight of a ship because the pressure increases with depth as a result of the weight of the vessel. Thus the pressure of the sea at the bottom of a ship (as it pushes down into the water) is greater than at the surface of the sea and this pressure difference results in a net upwards force on the vessel, keeping it afloat. Thus, the ship literally sits on a shelf of water that is strong enough (pressure) to offset the weight placed upon it, which is little different in principle than putting a rock on a bookshelf—if the rock’s weight is not too great for the shelf, it is supported. Which means, simply put, that the design of the ship, i.e., its weight ration to footprint, has to meet the buoyance principle involved—which is why an aircraft carrier, at 106,300 ton can float (a principle in my younger years that was beyond my comprehension).
    Because a vessel is in constant motion, it is also subjected to dynamic forces, that is the design of the vessel must include a hull design capable of resisting the bending moments, shear forces, and torsion resulting from the vessel’s weight distribution and the forces of wind and wave. Hulls obviously have to be flexible—if they are not, but are stiff they would break.
(See the next post, “Understanding Laman and Lemuel and Building the Ship – Part II,” for the concluding comments on this very important understanding of Nephi's ship and the Lord's involvement in its design and construction)

2 comments:

  1. My dear ol father-in- law found some plans in some magazine to build a fishing boat. It took 15 years or more to build. After sitting around years after that we took the boat to San Diego bay for its maiden voyage. Well as it turned out it did float but only had about 4inchs of freeboard above the water. It wouldn't take much of a wave to swamp the thing. Well that was the first and last trip. Moral of the story - trust the Lord to know how to buildem and not the father-in-law.

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  2. Thanks for the laugh. Made my day.

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