A flood is an overflow of water that submerges land, dry. In the sense of "flowing water", the word may be applied to the inflow of the tide. Floods are an area of study of the discipline hydrology and are of significant concern in agriculture, civil engineering and public health. Flooding may occur as an overflow of water from water bodies, such as a river, lake, or ocean, in which the water overtops or breaks levees, resulting in some of that water escaping its usual boundaries, or it may occur due to an accumulation of rainwater on saturated ground in an areal flood. While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, these changes in size are unlikely to be considered significant unless they flood property or drown domestic animals. Floods can occur in rivers when the flow rate exceeds the capacity of the river channel at bends or meanders in the waterway. Floods cause damage to homes and businesses if they are in the natural flood plains of rivers.
While riverine flood damage can be eliminated by moving away from rivers and other bodies of water, people have traditionally lived and worked by rivers because the land is flat and fertile and because rivers provide easy travel and access to commerce and industry. Some floods develop while others such as flash floods can develop in just a few minutes and without visible signs of rain. Additionally, floods can be local, impacting a neighborhood or community, or large, affecting entire river basins; the word "flood" comes from a word common to Germanic languages. Floods can happen on flat or low-lying areas when water is supplied by rainfall or snowmelt more than it can either infiltrate or run off; the excess accumulates in place, sometimes to hazardous depths. Surface soil can become saturated, which stops infiltration, where the water table is shallow, such as a floodplain, or from intense rain from one or a series of storms. Infiltration is slow to negligible through frozen ground, concrete, paving, or roofs.
Areal flooding begins in flat areas like floodplains and in local depressions not connected to a stream channel, because the velocity of overland flow depends on the surface slope. Endorheic basins may experience areal flooding during periods when precipitation exceeds evaporation. Floods occur in all types of river and stream channels, from the smallest ephemeral streams in humid zones to normally-dry channels in arid climates to the world's largest rivers; when overland flow occurs on tilled fields, it can result in a muddy flood where sediments are picked up by run off and carried as suspended matter or bed load. Localized flooding may be caused or exacerbated by drainage obstructions such as landslides, debris, or beaver dams. Slow-rising floods most occur in large rivers with large catchment areas; the increase in flow may be the result of sustained rainfall, rapid snow melt, monsoons, or tropical cyclones. However, large rivers may have rapid flooding events in areas with dry climate, since they may have large basins but small river channels and rainfall can be intense in smaller areas of those basins.
Rapid flooding events, including flash floods, more occur on smaller rivers, rivers with steep valleys, rivers that flow for much of their length over impermeable terrain, or normally-dry channels. The cause may be localized convective precipitation or sudden release from an upstream impoundment created behind a dam, landslide, or glacier. In one instance, a flash flood killed eight people enjoying the water on a Sunday afternoon at a popular waterfall in a narrow canyon. Without any observed rainfall, the flow rate increased from about 50 to 1,500 cubic feet per second in just one minute. Two larger floods occurred at the same site within a week, but no one was at the waterfall on those days; the deadly flood resulted from a thunderstorm over part of the drainage basin, where steep, bare rock slopes are common and the thin soil was saturated. Flash floods are the most common flood type in normally-dry channels in arid zones, known as arroyos in the southwest United States and many other names elsewhere.
In that setting, the first flood water to arrive is depleted. The leading edge of the flood thus advances more than and higher flows; as a result, the rising limb of the hydrograph becomes quicker as the flood moves downstream, until the flow rate is so great that the depletion by wetting soil becomes insignificant. Flooding in estuaries is caused by a combination of sea tidal surges caused by winds and low barometric pressure, they may be exacerbated by high upstream river flow. Coastal areas may be flooded by storm events at sea, resulting in waves over-topping defenses or in severe cases by tsunami or tropical cyclones. A storm surge, from either a tropical cyclone or an extratropical cyclone, falls within this category. Research from the NHC explains: "Storm surge is an abnormal rise of water generated by a storm and above the predicted astronomical tides. Storm surge should not be confused with storm tide, defined as the water level rise due to the combination of storm surge and the astronomical tide.
This rise in water level can cause extreme flooding in coastal areas when storm surge coincides with normal high tide, resulting in storm tides reaching up to 20 feet or more in some cases." Urban flooding is the inundation of land or property in a built environment in more densely populated areas, caused by rainfall overwhelmi
Stepan Osipovich Makarov was a Russian vice-admiral, a accomplished and decorated commander of the Imperial Russian Navy, an oceanographer, awarded by the Russian Academy of Sciences, author of several books. Makarov designed a small number of ships; the town of Shiritoru on Sakhalin island was renamed Makarov in 1946 in his honor. Stepan Makarov was born in Nikolaev in a family of a fleet praporshchik, his family moved to Nikolayevsk na Amure in 1858 and Makarov attended school there. In 1863, he joined the Imperial Russian Navy where he served as a cadet aboard a clipper of the Russian Pacific Fleet. In 1866 he took part in the voyage of the corvette Askold from Vladivostok to Kronstadt via the Cape of Good Hope. Makarov served with the Baltic Fleet between 1867 and 1876 serving as flag captain under Admiral Andrei Popov, he transferred to the Black Sea Fleet in 1876. In 1870, Makarov invented a design for a collision mat; the invention was displayed at the 1873 Vienna World's Fair. Makarov was decorated for his service as a captain of the Russian torpedo boat tender Velikiy Knyaz Konstantin in the Russo-Turkish War of 1877–78.
He was one of the first to adopt the idea of using flotillas of torpedo boats and had combat experience as a torpedo boat commander. On 14 January 1878 he launched torpedoes from a boat sinking the Ottoman Navy vessel Intibakh at Batumi in the world's first successful attack using the self-propelled Whitehead torpedo. From 1879–1880, he was part of the maritime contingent during the Russian conquest of Central Asia, he was promoted to captain, 1st rank, on 1 January 1881. Over the next two decades, Makarov specialized in naval research, publishing over fifty papers on oceanography and naval tactics; as captain of the corvette Vityaz, Makarov directed a round-the-world oceanographic expedition from 1886–89. When Makarov was promoted to rear admiral in 1890, he was the youngest person to reach such a position in the history of the Russian navy. From 1890–1894, Makarov was Chief Inspector of Naval Ordinance, during which time he invented the "Makarov cap", an armor-piercing projectile whose design was soon copied by all navies.
From 1894–1895, Makarov was commander of the Mediterranean Squadron. From 1895–1896, Makarov was in charge of naval training, he became a vice admiral in 1896, began to concentrate on the design for new warships icebreakers needed to establish a northern sea route between Europe and East Asia. Makarov led an expedition to survey the mouths of the Ob and the Yenisei Rivers in 1897; as part of his research on icebreaking methods, Makarov visited the Great Lakes of North America in 1898 to study methods in use by railroad ferries in winter. He proposed the world's first polar icebreaker, oversaw her construction, commanded her on her maiden voyage in 1899. In 1899, Makarov was appointed commander and military governor of Kronstadt in January 1900. In 1901, Makarov commanded Yermak on an Arctic expedition to survey the coasts of Novaya Zemlya and Franz Josef Land. Makarov designed two icebreaking steamships to connect the Trans-Siberian Railway across Lake Baikal: the train ferry SS Baikal built in 1897 and passenger and package freight steamer SS Angara built in about 1900, based upon his study of similar vessels on the North American Great Lakes.
Armstrong Whitworth in Newcastle-upon-Tyne, built the ships in kit form and sent them to Listvyanka on Lake Baikal for reassembly. Their boilers and some other components were built in Saint Petersburg. Baikal had 15 boilers, four funnels, was 64 metres long and could carry 24 railway coaches and one locomotive on her middle deck. Angara is smaller, with two funnels. Baikal was destroyed in the Russian Civil War. Angara survives, has been restored and is permanently moored at Irkutsk where she serves as offices and a museum. After the Imperial Japanese Navy's surprise attack at Port Arthur on 9 February 1904, Admiral Makarov was sent to command the Imperial Russian Navy's battle fleet stationed there on 24 February, establishing the battleship Petropavlovsk as his flagship, his leadership differed from any other Russian naval officer during this war, offering diversity, an ability to "inspire confidence in his subordinates". Upon his assumption of command in early 1904, Makarov increased the activity in the Russian squadrons, as well as the general defense of Port Arthur.
Until the Russian fleet had done nothing but exist, as a fleet in being. Under Makarov's leadership, "Russian squadrons put to sea nearly every day on the move, ensuring that it was never taken by surprise outside the protection of Port Arthur's" shore batteries. Unlike his predecessors, Makarov sought engagements with the Japanese, kept his vessels in an order of battle in the roadstead of Port Arthur; when Japanese cruisers bombarded Port Arthur from the Yellow Sea in March, his cruisers returned fire with such intensity that the Japanese ships were forced to withdraw. That same month the Japanese Navy tried to seal the port's entrance by sinking a number of old steamships as blockships in the harbor's channel. Russian cruisers assigned to protect the entrance pursued the escorting Japanese warships and put them to flight. On 13 April 1904 the Russian destroyer Strasny returning from patrol, tried to re-enter the mouth of the Port Arthur but was intercepted by Japanese destroyers. An engagement began between the opposing destroyers, when observed by Makarov he sent the
A compartment is a portion of the space within a ship defined vertically between decks and horizontally between bulkheads. It is analogous to a room within a building, may provide watertight subdivision of the ship's hull important in retaining buoyancy if the hull is damaged. Subdivision of a ship's hull into watertight compartments is called compartmentation. Bulkhead watertight compartments were invented by the Chinese which strengthened the junks and slowed flooding in case of holing during the Han and Song dynasties; the wide application of Chinese watertight compartments soon spread to the Europeans through the Indian and Arab merchants. Watertight subdivision limits loss of buoyancy and freeboard in the event of damage, may protect vital machinery from flooding. Most ships have some pumping capacity to remove accumulated water from the bilges, but a steel ship with no watertight subdivision will sink if water accumulates faster than pumps can remove it. Standards of watertight subdivision assume no dewatering capability, although pumps kept in working order may provide an additional measure of safety in the event of minor leaks.
The most common watertight subdivision is accomplished with transverse bulkheads dividing the elongated hull into a number of watertight floodable lengths. Early watertight subdivision tested with hoses sometimes failed to withstand the hydrostatic pressure of an adjoining flooded compartment. Effective watertight subdivision requires these transverse bulkheads to be both watertight and structurally sound. A ship will sink if the transverse bulkheads are so far apart that flooding a single compartment would consume all the ship's reserve buoyancy. Aside from the possible protection of machinery, or areas most susceptible to damage, such a ship would be no better than a ship without watertight subdivision, is called a one-compartment ship. A ship capable of remaining afloat when any single watertight compartment is flooded is called a two-compartment ship, but damage destroying the tightness of a transverse bulkhead may cause flooding of two compartments and loss of the ship. A ship able to remain afloat with any two compartments flooded is called a three-compartment ship, will withstand damage to one transverse bulkhead.
After the Titanic sinking, safety standards recommended spacing transverse bulkheads so no single point of damage would either submerge the end of the upper bulkhead deck or reduce bulkhead deck freeboard to less than 3 inches. Wartime experience with torpedo damage indicated the typical damage diameter of 35 feet defined a practical minimum distance for transverse bulkhead spacing. Three types of doors are used between compartments. A closed watertight door is structurally capable of withstanding the same pressures as the watertight bulkheads they penetrate, although such doors require frequent maintenance to maintain effective seals, must, of course, be kept closed to contain flooding. A closed weathertight door can seal out spray and periodic minor flow over weather decks, but may leak during immersion; these outward opening doors are useful at weather deck entrances to compartments above the main deck. Joiner doors are similar to doors used in conventional buildings ashore, they afford privacy and temperature control for compartments formed by non-structural bulkheads within the ship's hull.
Compartments are identified by the deck forming the floor of that compartment. Different types of ships have different deck naming conventions. Passenger ships use letters of the alphabet sequentially down from A deck above B deck, B deck above C deck, so forth. Another popular naming convention is numbering the main deck 1, the deck below it 2, the deck below that the third deck, so forth. Decks above the main deck may be named, like the bridge deck or poop deck, or they may be numbered upwards from the main deck with a zero prefix: 01 above the main deck, 02 deck above 01, so forth; the United States Navy has used the latter convention in a compartment numbering system since 1949. The USN system identifies each compartment by a four-part code separated by hyphens; the first part of the code represents a numbered deck, the second part of the code is a hull support frame numbered sequentially from the bow, the third part of the code is a number representing compartment position with respect to the ship's centerline, the fourth part of the code is alphabetic representing the use of that compartment.
The centerline position code is zero for a compartment on the ship's centerline, odd numbers for compartments to starboard of the centerline, for compartments to port. For compartments sharing the same deck and forward frame, the first two parts of the code are identical, the third part of the code is numbered outward from the centerline. For example, four main-deck compartments at frame 90 would be 1-90-1-L inboard and 1-90-3-L outboard on the starboard side of the ship and 1-90-2-L inboard and 1-90-4-L outboard on the port side; the fourth part of the code is: A for store rooms C for manned communication or control centers E for manned engineering machinery spaces F for oil storage tanks G for gasoline-storage tanks J for JP-5 storage tanks K for chemical-storage spaces L for living spaces, including sleeping, washrooms, sick bay, passageways. M for ammunition magazines Q for miscellaneous spaces not otherwise coded, including laundry, pantries, wiring trunks, unmanned engineering and electronic spaces and offices.
T for vertical-access trunks V for void spaces W for George Charles. Manual of
Zhu Yu (author)
Zhu Yu was a Chinese author and historian of the Song Dynasty. He retired in Huang Gang of the Hubei province, bought a country house and named it "Pingzhou", he called himself "Expert Vegetable Grower of Pingzhou". Between 1111 and 1117 AD, Zhu Yu wrote the book Pingzhou Ketan, published in 1119 AD, it covered a wide variety of maritime issues in China at the time. His extensive knowledge of maritime engagements and practices were because his father, Zhu Fu, was the Port Superintendent of Merchant Shipping for Guangzhou from 1094 until 1099 AD, whereupon he was elevated to the status of governor there and served in that office until 1102 AD. In terms of global significance, Zhu Yu's book was the first book in history to mention the use of the mariner's magnetic-needle compass for navigation at sea. Although the compass needle was first described in detail by the Chinese scientist Shen Kuo in his Dream Pool Essays of 1088 AD, he did not outline its use for navigation at sea; the passage from Zhu Yu's Pingzhou Ketan relating to the use of the compass states: According to government regulations concerning seagoing ships, the larger ones can carry several hundred men, the smaller ones may have more than a hundred men on board.
One of the most important merchants is chosen to be Leader, another is Deputy Leader, a third is Business Manager. The Superintendent of Merchant Shipping gives them an unofficially sealed red certificate permitting them to use the light bamboo for punishing their company when necessary. Should anyone die at sea, his property becomes forfeit to the government... The ship's pilots are acquainted with the configuration of the coasts. In dark weather they look at the south-pointing needle, they use a line a hundred feet long with a hook at the end which they let down to take samples of mud from the sea-bottom. Although Zhu began writing his book in 1111 AD, it referred to events concerning various seaports of China from the year 1086 onwards. Therefore, it is plausible that since the time that Shen Kuo began writing his book, the compass needle was being used for navigation. Beyond the compass, Zhu's book described many other maritime subjects. Zhu Yu's book described the use of the for-and-aft lug, taut mat sails, the practice of beating-to-windward.
Zhu described bulkhead builds in the hulls of Chinese ships for creating watertight compartments. Therefore, if a ship's hull was damaged, only one compartment would fill with water while the ship could be salvaged without sinking. Zhu Yu wrote. Expert divers were written of by many Chinese authors, including Song Yingxing who wrote about pearl divers that used watertight leather face masks attached with breathing tubes secured with tin rings that led up to the surface, allowing them to breathe underwater for long periods of time. Since at least the Tang Dynasty, the Chinese had a formula for a waterproof cream applied to silk clothes that proved useful for divers. Confirming Zhu Yu's writing on Song Dynasty ships with bulkhead hull compartments, in 1973 a 24 m long, 9 m wide Song Dynasty trade ship from circa 1277 AD was dredged from the water off the southern coast of China. Chinese literature History of the Song Dynasty Technology of the Song Dynasty Wujing Zongyao South-pointing chariot Alexander Neckam Ebrey, Palais.
East Asia: A Cultural and Political History. Boston: Houghton Mifflin Company. Needham, Joseph. Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 1, Physics. Taipei: Caves Books Ltd. Needham, Joseph. Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 3, Civil Engineering and Nautics. Taipei: Caves Books Ltd. Needham, Joseph. Science and Civilization in China, Volume 5, Chemistry and Chemical Technology, Part 4, Spagyrical Discovery and Invention: Apparatus and Gifts. Taipei: Caves Books Ltd. Sivin, Nathan. Science in Ancient China: Researches and Reflections. Brookfield, Vermont: VARIORUM, Ashgate Publishing
Buoyancy or upthrust, is an upward force exerted by a fluid that opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid, thus the pressure at the bottom of a column of fluid is greater than at the top of the column. The pressure at the bottom of an object submerged in a fluid is greater than at the top of the object; the pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, is equivalent to the weight of the fluid that would otherwise occupy the volume of the object, i.e. the displaced fluid. For this reason, an object whose average density is greater than that of the fluid in which it is submerged tends to sink. If the object is less dense than the liquid, the force can keep the object afloat; this can occur only in a non-inertial reference frame, which either has a gravitational field or is accelerating due to a force other than gravity defining a "downward" direction.
The center of buoyancy of an object is the centroid of the displaced volume of fluid. Archimedes' principle is named after Archimedes of Syracuse, who first discovered this law in 212 B. C. For objects and sunken, in gases as well as liquids, Archimedes' principle may be stated thus in terms of forces: Any object, wholly or immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object — with the clarifications that for a sunken object the volume of displaced fluid is the volume of the object, for a floating object on a liquid, the weight of the displaced liquid is the weight of the object. More tersely: buoyancy = weight of displaced fluid. Archimedes' principle does not consider the surface tension acting on the body, but this additional force modifies only the amount of fluid displaced and the spatial distribution of the displacement, so the principle that buoyancy = weight of displaced fluid remains valid; the weight of the displaced fluid is directly proportional to the volume of the displaced fluid.
In simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. Thus, among submerged objects with equal masses, objects with greater volume have greater buoyancy; this is known as upthrust. Suppose a rock's weight is measured as 10 newtons when suspended by a string in a vacuum with gravity acting upon it. Suppose that when the rock is lowered into water, it displaces water of weight 3 newtons; the force it exerts on the string from which it hangs would be 10 newtons minus the 3 newtons of buoyancy force: 10 − 3 = 7 newtons. Buoyancy reduces the apparent weight of objects that have sunk to the sea floor, it is easier to lift an object up through the water than it is to pull it out of the water. Assuming Archimedes' principle to be reformulated as follows, apparent immersed weight = weight − weight of displaced fluid inserted into the quotient of weights, expanded by the mutual volume density density of fluid = weight weight of displaced fluid, yields the formula below.
The density of the immersed object relative to the density of the fluid can be calculated without measuring any volumes.: density of object density of fluid = weight weight − apparent immersed weight Example: If you drop wood into water, buoyancy will keep it afloat. Example: A helium balloon in a moving car. During a period of increasing speed, the air mass inside the car moves in the direction opposite to the car's acceleration; the balloon is pulled this way. However, because the balloon is buoyant relative to the air, it ends up being pushed "out of the way", will drift in the same direction as the car's acceleration. If the car slows down, the same balloon will begin to drift backward. For the same reason, as the car goes round a curve, the balloon will drift towards the inside of the curve; the equation to calculate the pressure inside a fluid in equilibrium is: f + div σ = 0 where f is the force density exerted by some outer field on the fluid, σ is the Cauchy stress tensor. In this case the stress tensor is proportional to the identity tensor: σ i j = − p δ i j.
Here δij is the Kronecker delta. Using this the above equation becomes: f = ∇ p. Assuming the outer force field is conservative, it can be written as the negative gradient of some scalar valued function: f = − ∇
Persons who are in the Damage controlman rating are the Navy's and Coast Guard’s maintenance and emergency repair specialists. Coast Guard damage controlmen assigned to cutters are responsible for maintaining watertight integrity, emergency equipment associated with firefighting and Shipboard flooding. Train others on board ship of firefighting and repairs of damage to its infrastructure. Are involved with the engineering watches and associated duties, since it is an engineering rating. DCs assigned ashore are responsible for the maintenance and repairs to facility structures and Coast Guard–owned housing units. Shore-side responsibilities include repairs and installations to roofs, sheetrock, doors, cabinets, plumbing fixtures, appliances, as well as many types of welding repairs; the shore-side DC performs small construction and renovations projects. Additionally, assist with nearby cutters' or small boats' maintenance. Most Coast Guard stations will require cross training of other duties, including engineering for a rounded, well trained, better response and safer station organization.
Navy DCs do the work necessary for damage control, ship stability, fire prevention, chemical and radiological warfare defense. They instruct personnel in the methods of damage control and chemical and radiological defense, repair damage control equipment and systems. After completion of "A" school, USN damage controlmen are assigned to ships of all types in the United States or overseas, TAR damage controlmen are assigned to NRF ships in CONUS. In a typical 20-year period in the Navy, they spend about 65 percent of their time on sea duty and about 35 percent on shore duty. Upon completing sea tours, USN damage controlmen will be assigned to shore duty in fleet concentration areas. TAR damage controlmen will be assigned to reserve centers across the nation. While assigned to a reserve center TAR damage controlmen will train and administer selected reserve personnel. List of United States Navy ratings List of United States Coast Guard ratings Damage Controlman DC - usmilitary.about.com Description of Coast Guard duties
A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying passengers or goods, or in support of specialized missions, such as defense and fishing. A "ship" was a sailing vessel with at least three square-rigged masts and a full bowsprit. Ships are distinguished from boats, based on size, load capacity, tradition. Ships have been important contributors to human commerce, they have supported the spread of colonization and the slave trade, but have served scientific and humanitarian needs. After the 15th century, new crops that had come from and to the Americas via the European seafarers contributed to the world population growth. Ship transport is responsible for the largest portion of world commerce; as of 2016, there were more than 49,000 merchant ships, totaling 1.8 billion dead weight tons. Of these 28% were oil tankers, 43% were bulk carriers, 13% were container ships. Ships are larger than boats, but there is no universally accepted distinction between the two.
Ships can remain at sea for longer periods of time than boats. A legal definition of ship from Indian case law is a vessel. A common notion is, but not vice versa. A US Navy rule of thumb is that ships heel towards the outside of a sharp turn, whereas boats heel towards the inside because of the relative location of the center of mass versus the center of buoyancy. American and British 19th Century maritime law distinguished "vessels" from other craft. In the Age of Sail, a full-rigged ship was a sailing vessel with at least three square-rigged masts and a full bowsprit. A number of large vessels are referred to as boats. Submarines are a prime example. Other types of large vessel which are traditionally called boats are Great Lakes freighters and ferryboats. Though large enough to carry their own boats and heavy cargoes, these vessels are designed for operation on inland or protected coastal waters. In most maritime traditions ships have individual names, modern ships may belong to a ship class named after its first ship.
In the northern parts of Europe and America a ship is traditionally referred to with a female grammatical gender, represented in English with the pronoun "she" if named after a man. This is not universal usage and some English language journalistic style guides advise using "it" as referring to ships with female pronouns can be seen as offensive and outdated. In many documents the ship name is introduced with a ship prefix being an abbreviation of the ship class, for example "MS" or "SV", making it easier to distinguish a ship name from other individual names in a text; the first known vessels could not be described as ships. The first navigators began to use animal skins or woven fabrics as sails. Affixed to the top of a pole set upright in a boat, these sails gave early ships range; this allowed men to explore allowing for the settlement of Oceania for example. By around 3000 BC, Ancient Egyptians knew, they used woven straps to lash the planks together, reeds or grass stuffed between the planks helped to seal the seams.
The Greek historian and geographer Agatharchides had documented ship-faring among the early Egyptians: "During the prosperous period of the Old Kingdom, between the 30th and 25th centuries BC, the river-routes were kept in order, Egyptian ships sailed the Red Sea as far as the myrrh-country." Sneferu's ancient cedar wood ship Praise of the Two Lands is the first reference recorded to a ship being referred to by name. The ancient Egyptians were at ease building sailboats. A remarkable example of their shipbuilding skills was the Khufu ship, a vessel 143 feet in length entombed at the foot of the Great Pyramid of Giza around 2500 BC and found intact in 1954, it is known that ancient Nubia/Axum traded with India, there is evidence that ships from Northeast Africa may have sailed back and forth between India/Sri Lanka and Nubia trading goods and to Persia and Rome. Aksum was known by the Greeks for having seaports for ships from Yemen. Elsewhere in Northeast Africa, the Periplus of the Red Sea reports that Somalis, through their northern ports such as Zeila and Berbera, were trading frankincense and other items with the inhabitants of the Arabian Peninsula well before the arrival of Islam as well as with Roman-controlled Egypt.
A panel found at Mohenjodaro depicted a sailing craft. Vessels were of many types; this treatise gives a technical exposition on the techniques of shipbuilding. It sets forth minute details about the various types of ships, their sizes, the materials from which they were built; the Yukti Kalpa Taru sums up in a condensed form all the available information. The Yukti Kalpa Taru gives sufficient information and dates to prove that, in ancient times, Indian shipbuilders had a good knowledge of the materials which were used in building ships. In addition to describing the qualities of the different types of wood and their suitability for shipbuilding, the Yukti Kalpa Taru gives an elaborate classification of ships based on their size; the oldest discovered sea faring hulled boat is the Late Bronze Age Uluburun shipwreck off the coast of Turkey, dating back to 1300 BC. The Phoenicians, the first to sail around