The P2 transport was a United States Maritime Commission design for a passenger ship which could be converted into a troop transport. Three variants of the design were built, the P2-SE2-R1, P2-S2-R2, P2-SE2-R3. Ten P2-SE2-R1 ships were ordered by the Maritime Commission in World War II; the ships were laid down by the Bethlehem Shipbuilding Corporation in California. The intended use of these ships after the war was trans-Pacific service; as ordered, the ships were named after U. S. Navy admirals. Only eight ships were completed as troop transports for the navy, with the last two ships canceled on 16 December 1944. Despite being canceled, the last two ships were completed after the war to the P2-SE2-R3 design as civilian ships. In 1946 the ships were all decommissioned by the navy and transferred back to the Maritime Commission, from there to the United States Army; the army operated them with civilian crews as part of the Army Transport Service and renamed them after generals of the United States Army.
In 1950 the ships were transferred back the navy, but not recommissioned. Instead they were assigned to the Military Sea Transportation Service, manned by a civil service crew, keeping the names the army had given them. Eleven P2-S2-R2 ships were ordered by the Maritime Commission in World War II; the ships were laid down by Dry Dock Company of Kearny, New Jersey. The intended use of these ships after the War was for South American service; as ordered, the ships were all named after United States Army generals. Unlike the Admirals, the Generals did not have a uniform life after World War II. Three were transferred to the Army as the Admirals had been, of which one was disposed of by the Army and converted to a passenger liner before the Korean War. Five were retained by the Navy and were transferred to the Military Sea Transportation Service in October 1949 to be manned by civilian crews, two others were transferred to American President Lines with the intent of being converted to a passenger liners, but ended up being chartered troop ships that in the Korean War were rejoined to military control as part of the Military Sea Transportation Service.
As noted above, the last two Admirals were canceled in 1944 while under construction. They were completed to the P2-SE2-R3 design and operated by American President Lines as the SS President Cleveland and the SS President Wilson; the President Wilson was renamed SS Oriental Empress when sold to C. Y. Tung in 1978. United States Maritime Commission P-Type Passenger Ships The Ships List: American President Lines
USCGC Modoc was a 240-foot Tampa-class United States Coast Guard cutter designed for multi-mission roles. She had a top speed of sixteen knots, was armed with a pair of 5-inch deck guns. With the breakout of war she was armed with depth charges, additional guns and radar and transferred to the Navy. Modoc, along with her sister ships Tampa joined the Greenland Patrol; the ship is most remembered for her role in the sinking of the German battleship Bismarck. According to British intelligence chief William Stephenson's biography, A Man Called Intrepid, Modoc was rescuing survivors from torpedoed convoys in the Bay of Biscay when she came into visual contact with Bismarck which hitherto had been lost to pursuing British forces. Based upon her position, a U. S. piloted PBY patrol bomber went on to locate Bismarck in time for HMS Ark Royal to launch the air attacks that disabled her and enabled the British fleet to catch up and sink her. Modoc ended up in the middle of the battle. Anti-aircraft fire from Bismarck came close to hitting the ship.
In addition, HMS Norfolk was about to fire on the cutter when HMS Prince of Wales identified her as US Coast Guard. Despite all of the hectic action around the ship, she survived the war. Modoc was returned to the Treasury Department on December 1945, served as a patrol cutter until decommissioning in 1947, she was sold to a private owner and was converted to a merchant ship steaming Central and South American waters. After changing hands several times, Modoc was scrapped in 1964. Modoc was launched as a Coast Guard cutter by Union Construction Company in Oakland, California on 1 October 1921, she was sponsored by Jean Lemard. Modoc was placed in commission on 14 January 1922, she was one of four Tampa-class 240-foot cutters, the others being Haida and Tampa. These were the first USCG vessels with turbo-electric transmission and were the largest and most advanced cutters for their time. Home ported at Wilmington, North Carolina, Modoc began Atlantic ice patrol service with the International Ice Patrol in 1923.
For much of the next 18 years and another cutter alternated on 15-day patrols off the Grand Banks, using Halifax, Nova Scotia, Boston as their bases. Transferred to the United States Navy by Executive Order No. 8029 of 1 November 1941, Modoc joined the Greenland Patrol, whose orders were to do "a little of everything." This duty involved keeping convoy routes open and finding leads in ice for the Greenland convoys, escorting the convoys and rescuing survivors from torpedoed ships and maintaining aids to navigation, reporting weather conditions. Ships of the patrol were expected to discover and destroy enemy weather and radio stations in Greenland, continue hydrographic surveys, maintain communications, deliver supplies, conduct search and rescue operations. All of these duties, the Coast Guard performed with exemplary fortitude and faithfulness throughout the war, it was during this time that she was designated as WPG-46. In both World Wars, when submarines were more of a menace than icebergs, the International Ice Patrol was suspended so that the cutters could perform more important escort duty.
During these years there was but one major collision. Before she sank Modoc rescued 128 survivors. Modoc, in company with cutters Northland and General Greene rescuing survivors from torpedoed convoy ships, has witnessed a large part of German ship Bismarck's last battle 23 to 27 May 1941. Close to midnight 24 May Modoc found herself in the midst of an attack in which eight planes and three warships were involved. Antiaircraft fire from Bismarck whizzed dangerously close to the cutter's port bow. HMS Norfolk was about to take the cutter under fire until HMS Prince of Wales identified her as U. S. Coast Guard; the cutter was undamaged, although they were near the fighting and at times only six miles from Bismarck. The widespread movements of the combatants, 19 plus destroyers and smaller ships, had distributed danger over a wide area. Aircraft had played a continuous part in coordinating activities, thus adding to the danger of accidents to innocent bystanders, a role the cutters had to play prior to Pearl Harbor.
On the Greenland Ice Patrol plodded many of the Coast Guard's older and slower ships. They endured much discomfort amid the dangers of fog, storms and German raiders, but their work was vital to victory in the Atlantic. Modoc returned to the Treasury Department in accordance with Executive Order No. 9666 of 28 December 1945, served as a patrol cutter until decommissioning in 1947. Sold to Manuel Velliantis in Honduras, she was converted for merchant use and renamed Amalia V. Registered in Ecuador in 1960 by Tropical Navigation Co. she was renamed Machala, served as a merchantman until scrapped in 1964. Modoc received one battle star for World War II service. SteelNavy.com Modoc
USS Tullibee (SSN-597)
USS Tullibee, a unique submarine, was the second ship of the United States Navy to be named for the tullibee, any of several whitefishes of central and northern North America. At 273 feet long and 2,640 tons displacement, USS Tullibee was the smallest nuclear-powered attack submarine in the US submarine fleet; the initial manning complement was 60 enlisted men. However before inactivation, the crew over 100 enlisted men. During her career, Tullibee conducted many submarine firsts. During her commissioned service she submerged and surfaced 730 times and traveled 325,000 nautical miles equal to the distance from the earth to the moon and halfway back. Tullibee was the result of Project Nobska, a study ordered in 1956 by Admiral Arleigh Burke Chief of Naval Operations, from the Committee on Undersea Warfare of the National Academy of Sciences; that report emphasized the need for deeper-diving, ultraquiet submarine designs using long-range sonar. Tullibee incorporated three design changes based on Project Nobska.
First, it incorporated the first bow-mounted spherical sonar array. This required the second innovation: angled torpedo tubes. Thirdly, Tullibee was propelled by quiet turbo-electric transmission powered by a S2C reactor; the contract to build Tullibee was awarded to the Electric Boat Division of the General Dynamics Corporation on 15 November 1957. Her keel was laid down in Groton, Connecticut, on 26 May 1958, she was launched on 27 April 1960, sponsored by Mrs. John F. Davidson, the widow of Commander Charles F. Brindupke, commissioned on 9 November 1960, with Commander Richard E. Jortberg in command. Following her shakedown in January 1961, Tullibee engaged in sonar evaluations and nuclear submarine tactical exercises with Submarine Developmental Group 2, operating out of Naval Submarine Base New London, into 1963. During this period, the ship visited Bermuda on several occasions, as well as Puerto Rico. In July 1964, Tullibee participated in fleet exercises in anti-submarine warfare tactics with NATO units.
The submarine resumed developmental work in 1965 and operated in this capacity into the fall of that year. On 28 October, her home port was temporarily changed to Portsmouth, New Hampshire, when the ship entered the Portsmouth Naval Shipyard in Kittery, for an extensive overhaul, she remained in drydock for 754 days, emerging on 2 January 1968. Shifted back to New London, Tullibee deployed to the Caribbean Sea in January 1969 following refresher training and continued developmental work during 1969 and 1970. On 1 August 1970, Tullibee departed New London, bound for the Mediterranean and the ship's first service with the Sixth Fleet. During this period, she took part in NATO and Sixth Fleet exercises and made port visits to Athens, Greece. In early 1971, the submarine returned to developmental exercises once more to work on SSN tactics and made a port visit to Cape Canaveral, Florida. Participating in a major NATO exercise in the western Atlantic, Tullibee visited Halifax, Nova Scotia, before she received the Meritorious Unit Commendation for her contingency operations in the Mediterranean Sea during the previous year.
For the remainder of the year 1971, Tullibee operated in the western Atlantic on NATO and ASW exercises. During this period, Tullibee received the Arleigh Burke Fleet Trophy for significant improvement in the ship's battle efficiency and readiness for that fiscal year; the submarine conducted regular operations with the Atlantic Fleet Submarine Force into 1974, operating off the east coast and in the Caribbean Sea. Following one Caribbean cruise in the fall of 1974, Tullibee departed New London on 28 April 1975 for her second deployment to the Sixth Fleet. After operating in the Mediterranean into the fall of that year, the submarine returned to New London in October for an extended period of upkeep. Tullibee subsequently participated in sonar evaluation tests with British destroyer HMS Matapan in the Caribbean Sea in two separate deployments between April and June 1976, before undergoing another extended upkeep period; the submarine conducted ASW operations and local operations into the fall of 1976.
In October 1976, the ship received the "Golden Anchor" Award from the Commander in Chief, U. S. Atlantic Fleet, for meritorious retention, she departed New London on 12 November for her third Mediterranean deployment attached to the SIXTH Fleet. Tullibee conducted several significant SIXTH Fleet operations and participated in key NATO exercises, her excellence in the area of anti-submarine warfare during this patrol was acknowledged by the Commander U. S. SIXTH Fleet of the prestigious "HOOK'EM" Award for ASW Excellence in the spring of 1977, she returned to her home port on 24 April 1977 and during the remainder of the year, Tullibee underwent three upkeep periods interspersed with ASW exercises off the east coast of the United States. The early months of 1978 were spent in preparation for her fourth Mediterranean deployment. Departing New London in March, the submarine conducted operations with various units of the Sixth Fleet; the deployment was marred somewhat by a propulsion casualty which necessitated a two-month repair period spent at Rota, Spain.
Tullibee returned to New London on 30 August. Operations out of that port took Tullibee into 1979. On 24 July 1979, Commander Daniel J. Koczur relieved as the eighth Commanding Officer. During August 1979, Tullibee entered Portsmouth Naval Shipyard for its third and final major overhaul; this overhaul lasted until October 198
An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of rotation of a shaft. Electric motors can be powered by direct current sources, such as from batteries, motor vehicles or rectifiers, or by alternating current sources, such as a power grid, inverters or electrical generators. An electric generator is mechanically identical to an electric motor, but operates in the reverse direction, converting mechanical energy into electrical energy. Electric motors may be classified by considerations such as power source type, internal construction and type of motion output. In addition to AC versus DC types, motors may be brushed or brushless, may be of various phase, may be either air-cooled or liquid-cooled. General-purpose motors with standard dimensions and characteristics provide convenient mechanical power for industrial use.
The largest electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors are found in industrial fans and pumps, machine tools, household appliances, power tools and disk drives. Small motors may be found in electric watches. In certain applications, such as in regenerative braking with traction motors, electric motors can be used in reverse as generators to recover energy that might otherwise be lost as heat and friction. Electric motors produce linear or rotary force and can be distinguished from devices such as magnetic solenoids and loudspeakers that convert electricity into motion but do not generate usable mechanical force, which are referred to as actuators and transducers; the first electric motors were simple electrostatic devices described in experiments by Scottish monk Andrew Gordon and American experimenter Benjamin Franklin in the 1740s. The theoretical principle behind them, Coulomb's law, was discovered but not published, by Henry Cavendish in 1771.
This law was discovered independently by Charles-Augustin de Coulomb in 1785, who published it so that it is now known with his name. The invention of the electrochemical battery by Alessandro Volta in 1799 made possible the production of persistent electric currents. After the discovery of the interaction between such a current and a magnetic field, namely the electromagnetic interaction by Hans Christian Ørsted in 1820 much progress was soon made, it only took a few weeks for André-Marie Ampère to develop the first formulation of the electromagnetic interaction and present the Ampère's force law, that described the production of mechanical force by the interaction of an electric current and a magnetic field. The first demonstration of the effect with a rotary motion was given by Michael Faraday in 1821. A free-hanging wire was dipped into a pool of mercury; when a current was passed through the wire, the wire rotated around the magnet, showing that the current gave rise to a close circular magnetic field around the wire.
This motor is demonstrated in physics experiments, substituting brine for mercury. Barlow's wheel was an early refinement to this Faraday demonstration, although these and similar homopolar motors remained unsuited to practical application until late in the century. In 1827, Hungarian physicist Ányos Jedlik started experimenting with electromagnetic coils. After Jedlik solved the technical problems of continuous rotation with the invention of the commutator, he called his early devices "electromagnetic self-rotors". Although they were used only for teaching, in 1828 Jedlik demonstrated the first device to contain the three main components of practical DC motors: the stator and commutator; the device employed no permanent magnets, as the magnetic fields of both the stationary and revolving components were produced by the currents flowing through their windings. After many other more or less successful attempts with weak rotating and reciprocating apparatus Prussian Moritz von Jacobi created the first real rotating electric motor in May 1834.
It developed remarkable mechanical output power. His motor set a world record, which Jacobi improved four years in September 1838, his second motor was powerful enough to drive a boat with 14 people across a wide river. It was in 1839/40 that other developers managed to build motors with similar and higher performance; the first commutator DC electric motor capable of turning machinery was invented by British scientist William Sturgeon in 1832. Following Sturgeon's work, a commutator-type direct-current electric motor was built by American inventor Thomas Davenport, which he patented in 1837; the motors ran at up to 600 revolutions per minute, powered machine tools and a printing press. Due to the high cost of primary battery power, the motors were commercially unsuccessful and bankrupted Davenport. Several inventors followed Sturgeon in the development of DC motors, but all encountered the same battery cost issues; as no electricity distribution system was available at the time, no practical commercial market emerged for these motors.
In 1855, Jedlik built a device using similar principles to those used in his electromagnetic self-rotors, capable of useful work. He built a model electric vehicle that same year. A major turning point came in 1864; this featured symmetrically-grouped coils closed upon themselves and connected to the bars of a commutator, the brushes of which delivered non-fluctuating current. The first c
In its primitive form, a wheel is a circular block of a hard and durable material at whose center has been bored a circular hole through, placed an axle bearing about which the wheel rotates when a moment is applied by gravity or torque to the wheel about its axis, thereby making together one of the six simple machines. When placed vertically under a load-bearing platform or case, the wheel turning on the horizontal axle makes it possible to transport heavy loads; the English word wheel comes from the Old English word hweol, from Proto-Germanic *hwehwlan, *hwegwlan, from Proto-Indo-European *kwekwlo-, an extended form of the root *kwel- "to revolve, move around". Cognates within Indo-European include Icelandic hjól "wheel, tyre", Greek κύκλος kúklos, Sanskrit chakra, the latter two both meaning "circle" or "wheel"; the invention of the wheel falls into the late Neolithic, may be seen in conjunction with other technological advances that gave rise to the early Bronze Age. This implies the passage of several wheel-less millennia after the invention of agriculture and of pottery, during the Aceramic Neolithic.
4500–3300 BCE: Copper Age, invention of the potter's wheel. Precursors of wheels, known as "tournettes" or "slow wheels", were known in the Middle East by the 5th millennium BCE; these were made of stone or clay and secured to the ground with a peg in the center, but required significant effort to turn. True potter's wheels were in use in Mesopotamia by 3500 BCE and as early as 4000 BCE, the oldest surviving example, found in Ur, dates to 3100 BCE; the first evidence of wheeled vehicles appears in the second half of the 4th millennium BCE, near-simultaneously in Mesopotamia, the Northern and South Caucasus, Eastern Europe, so the question of which culture invented the wheeled vehicle is still unresolved. The earliest well-dated depiction of a wheeled vehicle is on the 3500–3350 BCE Bronocice clay pot excavated in a Funnelbeaker culture settlement in southern Poland. In nearby Olszanica 5000 BCE 2.2 m wide door were constructed for wagon entry. This barn was 40 m long with 3 doors; the oldest securely dated real wheel-axle combination, that from Stare Gmajne near Ljubljana in Slovenia is now dated within two standard deviations to 3340–3030 BCE, the axle to 3360–3045 BCE.
Two types of early Neolithic European wheel and axle are known. They both are dated to c. 3200–3000 BCE. In China, the wheel was present with the adoption of the chariot in c. 1200 BCE, although Barbieri-Low argues for earlier Chinese wheeled vehicles, c. 2000 BCE. In Britain, a large wooden wheel, measuring about 1 m in diameter, was uncovered at the Must Farm site in East Anglia in 2016; the specimen, dating from 1,100–800 BCE, represents the most complete and earliest of its type found in Britain. The wheel's hub is present. A horse's spine found; the wheel was found in a settlement built on stilts over wetland, indicating that the settlement had some sort of link to dry land. Although large-scale use of wheels did not occur in the Americas prior to European contact, numerous small wheeled artifacts, identified as children's toys, have been found in Mexican archeological sites, some dating to about 1500 BCE, it is thought that the primary obstacle to large-scale development of the wheel in the Americas was the absence of domesticated large animals which could be used to pull wheeled carriages.
The closest relative of cattle present in Americas in pre-Columbian times, the American Bison, is difficult to domesticate and was never domesticated by Native Americans. The only large animal, domesticated in the Western hemisphere, the llama, a pack animal but not physically suited to use as a draft animal to pull wheeled vehicles, did not spread far beyond the Andes by the time of the arrival of Columbus. Nubians from after about 400 BCE used wheels as water wheels, it is thought. It is known that Nubians used horse-drawn chariots imported from Egypt; the wheel was used, with the exception of the Horn of Africa, in Sub-Saharan Africa well into the 19th century but this changed with the arrival of the Europeans. Early wheels were simple wooden disks with a hole for the axle; some of the earliest wheels were made from horizontal slices of tree trunks