A shoulder mark called a shoulder board, rank slide, or slip-on, is a flat cloth sleeve worn on the shoulder strap of a uniform. It may bear rank or other insignia, should not be confused with an epaulette, although the two terms are used interchangeably; the newer Auscam uniform design lacks shoulder marks, instead opting for a vertical strap in the middle of the chest region of the uniform. Rank insignia tags are slipped onto this strap. Unlike the older uniform designs, there are slip-ons for every rank in the Australian Defence Force; the older Auscam uniform designs featured shoulder straps, upon which slip-on rank insignia of Commissioned Officers could be affixed, non-commissioned officers in the Air Force and Navy only. No shoulder-strap slip-ons are available for enlisted members of the army, whereas the other two services had appropriate slip ons, who have rank patches sewed onto the uniform arms; this older design is no longer issued, but may still be seen on personnel whose most recent uniform issue pre-dates the use of the new design.
In the Canadian Forces, slip-ons displaying rank insignia and shoulder titles are worn on the shoulder straps of the No. 3 Service Dress shirt, overcoat and sweater. The slip-ons are worn on a similar-style strap located in the centre of the chest of the CADPAT shirt, jacket and raincoat. Slip-ons are not worn with Mess Dress. Based on the shoulder boards used by the United States Navy, the United States Army and Air Force developed the shoulder mark, a cloth tube with embroidered or pinned rank insignia. Army officer shoulder marks are colored depending on the branch with which the officer is affiliated, they have an 1/8-inch gold stripe below the embroidered grade insignia. In the Air Force, a similar stripe is limited to senior officers. Air Force general officers have an additional stripe at the near end. Enlisted and Air Force junior officer shoulder marks lack these distinctions; these are worn on all class B uniform shirts. US Navy officers wear shoulder boards on Summer White and Service Dress White uniforms, wool overcoats and reefers.
"Soft shoulder boards" are worn on long sleeve white shirts and on black sweaters worn with Service Khaki or Service Dress Blue uniforms. Coast Guard officers wear Naval style shoulderboards on all class B uniform shirts. Service dress uniforms in the U. S. air and land forces have a different style of shoulder board, a firm material with an underlying longitudinal strap. The corresponding jacket shoulder has two small loops traversing from rear to front, the open end of the shoulder board's strap is drawn through the two loops and affixed to the underside of the board; this hides all the means of attachments, leaving a firm, finished surface. This particular style is what U. S. Air Force personnel call a shoulder board; the shoulder sleeve is called an epaulette, the two are never confused. On the United States Army Blue Service Uniform, officers wear embroidered rank insignia "shoulder straps" mounted lengthwise on the outside shoulder seams; these are 1⅝ inches wide by 4 inches/3½ inches long, are sewn, snapped, or clipped onto each shoulder.
The Boy Scouts of America uses colored shoulder loops worn on the shoulder straps to indicate the program level. Webelos Scouts wearing tan uniforms and all Cub Scout leaders wear blue loops, Boy Scouts and leaders wear forest green loops, Varsity Scouts and leaders wear blaze loops, Venturers and leaders wear emerald green loops. Adults who hold a district or council position wear silver loops; the only youth permitted to wear gold loops are the National Chief, National Vice chief, Region Chiefs of the Order of the Arrow. Rank slides are used by all of the UK Armed Forces on working dress uniforms. Shoulder boards are worn by officers on tropical dress uniform, bearing the same insignia carried on the cuffs of the dress uniform. A slide worn on the chest is used to indicate rank for all RN personnel in Action Working Dress. In the British Army, shoulder straps are worn with service uniforms. In combat dress, rank insignia is displayed on'rank slides' worn on the chest. In the Royal Air Force, rank slides are worn by all ranks on the shoulders of working dress uniforms, on flying clothing and coveralls.
Similar rank slides are worn on a single tab on the chest of operational clothing. As a ranked organisation, members of St. John Ambulance wear rank slides on all uniforms. Colours are used to differentiate between different health care professionals; the uniforms of most police forces in the United Kingdom feature rank slides. At ranks below Inspector, the collar number is displayed on the shoulder, although some Inspectors and above are starting to display their collar number alongside their rank insignia; the most notable exception to this is Kent Police, whose officers display their collar number on the stab vest instead of the rank slides. Public order officers' shoulder slides are colour-coded according to their role: Silver commander – Grey Bronze commander – Yellow PSU commander – Red PSU sergeant – White Medic – Green Tactical adviser – Royal blue Evidence gatherer – Orange
A push-up is a common calisthenics exercise beginning from the prone position, or the front leaning rest position known in the military. By raising and lowering the body using the arms, push-ups exercise the pectoral muscles and anterior deltoids, with ancillary benefits to the rest of the deltoids, serratus anterior and the midsection as a whole. Push-ups are a basic exercise used in civilian athletic training or physical education and in military physical training, they are a common form of punishment used in the military, school sport, or in some martial arts disciplines. In the past this movement was called a floor dip; the American English term push-up was first used between 1905 and 1910, while the British press-up was first recorded between 1945 and 1950. According to the study published in Journal of Strength and Conditioning Research, the test subjects supported with their hands, on average, 69.16% of their body mass in the up position, 75.04% in the down position during the traditional push-ups.
In modified push-ups, where knees are used as the pivot point, subjects supported 53.56% and 61.80% of their body mass in up and down positions, respectively. While the push-up targets the muscles of the chest and shoulders, support required from other muscles results in a wider range of muscles integrated into the exercise; the rectus abdominis and transversus abdominis contract continually while performing push-ups to hold the body off the floor and keep the legs and torso aligned. The rectus abdominis spans the front of the abdomen and is the most prominent of the abdominal muscles; the transversus abdominis lies deep within the abdomen. Both muscles compress the abdomen, the rectus abdominis flexes the spine forward, although it does not execute this function when performing push-ups; the anterior portion of the deltoid muscle is one of the major shoulder-joint horizontal adductors, moving the upper arms toward the chest during the upward phase of a push-up. It helps control the speed of movement during the downward phase.
The deltoid attaches to parts of the clavicle and scapula, just above the shoulder joint on one end, to the outside of the humerus bone on the other. Along with horizontal adduction, the anterior deltoid assists with flexion and internal rotation of the humerus within the shoulder socket; the push up requires the work of many muscle groups, with one of the primary muscle groups being the chest muscles, the pectoralis major and the minor. These are the main pushing muscle group of the upper body; when pushing and lowering the body during a push up, the pectoralis major is doing most of the work. As a result, these muscles become strong and can become defined lean muscle after doing push-ups regularly; the push-up depends on stabilizer muscles as you lower the body. The erector spinae is the main stabilizer muscle in the back. Made up of 3 muscles including the spinalis and iliocostalis. Spinalis runs adjacent to the spine, the longissimus runs adjacent to the spinalis and the iliocostalis runs adjacent to the longissimus and over the ribs.
2 muscles called the gluteus gluteus minimus stabilize the upper leg. The medius and minimus sit under the largest butt muscle, the gluteus maximus. While the anterior deltoids and pectoralis major muscles work to horizontally adduct the upper arms during the upward phase of a push-up, the triceps brachii muscles, or triceps for short, are hard at work extending the elbow joints so the arms can be extended; the triceps control the speed of elbow-joint flexion during the downward phase of the exercise. The closer together the hands are placed during a push-up, the harder the triceps work; the muscle is divided into three heads -- long head and medial head. The lateral and medial heads attach to the back of the humerus bone, the long head attaches just behind the shoulder socket on one end. There is a special sub-set of the diamond push-up The special version of this push-up is when the diamond is placed directly below the nose instead of the solar plexus; the nose must touch the floor in the center of the diamond.
This special diamond push-up is done by the United States Marine Corps. The lips must come within 1 inch of the floor while keeping the neck in line with the straight spine to qualify as a valid push-up; this can be verified by placing a 1-inch foam disposable earplug on the floor in the center of the diamond and picking it up with the lips. Stabilizers include wrist and forearm muscles, the knee extensors, the hip/spine flexors, which all work isometrically to maintain a proper plank position in the standard prone push-up. During the push-up exercise, the short head of the biceps brachii muscle acts as a dynamic stabilizer; this means the muscle activates at both ends—the elbow and the shoulder—to help stabilize the joints. Inner muscles that support the operation of the fingers, wrists and elbows are worked isometrically; some push-up modifications that require to have the arms at different heights engage the rotator cuff. In the "full push-up", the back and legs are straight and off the floor.
There are several variations besides the common push-up. These include bringing the thumbs and index fingers of both hands together as well as having the elbows pointed towards the knees; these variations are intended to put greater emphasis on the triceps or shoulders, rather
Naval Station Newport
The Naval Station Newport is a United States Navy base located in the city of Newport and the town of Middletown, Rhode Island. Naval Station Newport is home to the Naval Justice School, it once was the homeport for Cruiser Destroyer Force Atlantic, which relocated to Naval Station Norfolk in the early 1970s. Newport now maintains inactive ships at its pier facilities, along with the United States Coast Guard. In BRAC 2005, NAVSTA Newport gained over five hundred billets, in addition to receiving, the Officer Candidate School, the Naval Supply Corps School, several other activities, to include a few Army Reserve units. Naval Station Newport provides the facilities and infrastructure essential to support the operations of tenant commands and visiting fleet units. USS Constellation Naval Training Station 1919 Newport sex scandal The station was home of the decommissioned USS Saratoga after the departure of the USS Forrestal which departed under tow for the inactive ship storage facility in Philadelphia.
On May 8, 2014, Naval Sea Systems Command announced that ESCO Marine, Texas, would scrap Saratoga for one cent. The Rhode Island Aviation Hall of Fame is trying to move the decommissioned USS John F. Kennedy moored at Pier 2 at the station. Naval Health Clinic New England provides the health care facilities. NavyExplosive Ordnance Disposal Mobile Unit 2, Detachment Coastal Riverine Squadron 8 7th Naval Construction Regiment Naval Mobile Construction Battalion 27 Det 1627 Naval Undersea Warfare Center Naval Academy Preparatory School Naval Justice School Navy Supply Corps School Naval War College Officer Candidate School Officer Development School Direct Commission Officer Indoctrination Course Senior Enlisted Academy Surface Warfare Officers School NAVFAC Mid-Atlantic Public Works Department Newport Navy Operational Support Center Newport Navy Band NortheastMarine CorpsMarine Corps Detachment Newport Coast GuardUSCGC Ida Lewis USCGC Juniper USCGC Willow USCG Electronics Support Detachment Detal Castle Hill USCG Maintenance Augmentation Team NewportNational Oceanic and Atmospheric AdministrationNOAAS Henry B.
Bigelow Official Website Naval Station Newport at Global Security
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another. The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, space navigation, it is the term of art used for the specialized knowledge used by navigators to perform navigation tasks. All navigational techniques involve locating the navigator's position compared to known locations or patterns. Navigation, in a broader sense, can refer to any skill or study that involves the determination of position and direction. In this sense, navigation includes pedestrian navigation. In the European medieval period, navigation was considered part of the set of seven mechanical arts, none of which were used for long voyages across open ocean. Polynesian navigation is the earliest form of open-ocean navigation, it was based on memory and observation recorded on scientific instruments like the Marshall Islands Stick Charts of Ocean Swells.
Early Pacific Polynesians used the motion of stars, the position of certain wildlife species, or the size of waves to find the path from one island to another. Maritime navigation using scientific instruments such as the mariner's astrolabe first occurred in the Mediterranean during the Middle Ages. Although land astrolabes were invented in the Hellenistic period and existed in classical antiquity and the Islamic Golden Age, the oldest record of a sea astrolabe is that of Majorcan astronomer Ramon Llull dating from 1295; the perfecting of this navigation instrument is attributed to Portuguese navigators during early Portuguese discoveries in the Age of Discovery. The earliest known description of how to make and use a sea astrolabe comes from Spanish cosmographer Martín Cortés de Albacar's Arte de Navegar published in 1551, based on the principle of the archipendulum used in constructing the Egyptian pyramids. Open-seas navigation using the astrolabe and the compass started during the Age of Discovery in the 15th century.
The Portuguese began systematically exploring the Atlantic coast of Africa from 1418, under the sponsorship of Prince Henry. In 1488 Bartolomeu Dias reached the Indian Ocean by this route. In 1492 the Spanish monarchs funded Christopher Columbus's expedition to sail west to reach the Indies by crossing the Atlantic, which resulted in the Discovery of the Americas. In 1498, a Portuguese expedition commanded by Vasco da Gama reached India by sailing around Africa, opening up direct trade with Asia. Soon, the Portuguese sailed further eastward, to the Spice Islands in 1512, landing in China one year later; the first circumnavigation of the earth was completed in 1522 with the Magellan-Elcano expedition, a Spanish voyage of discovery led by Portuguese explorer Ferdinand Magellan and completed by Spanish navigator Juan Sebastián Elcano after the former's death in the Philippines in 1521. The fleet of seven ships sailed from Sanlúcar de Barrameda in Southern Spain in 1519, crossed the Atlantic Ocean and after several stopovers rounded the southern tip of South America.
Some ships were lost, but the remaining fleet continued across the Pacific making a number of discoveries including Guam and the Philippines. By only two galleons were left from the original seven; the Victoria led by Elcano sailed across the Indian Ocean and north along the coast of Africa, to arrive in Spain in 1522, three years after its departure. The Trinidad sailed east from the Philippines, trying to find a maritime path back to the Americas, but was unsuccessful; the eastward route across the Pacific known as the tornaviaje was only discovered forty years when Spanish cosmographer Andrés de Urdaneta sailed from the Philippines, north to parallel 39°, hit the eastward Kuroshio Current which took its galleon across the Pacific. He arrived in Acapulco on October 8, 1565; the term stems from the 1530s, from Latin navigationem, from navigatus, pp. of navigare "to sail, sail over, go by sea, steer a ship," from navis "ship" and the root of agere "to drive". The latitude of a place on Earth is its angular distance north or south of the equator.
Latitude is expressed in degrees ranging from 0° at the Equator to 90° at the North and South poles. The latitude of the North Pole is 90° N, the latitude of the South Pole is 90° S. Mariners calculated latitude in the Northern Hemisphere by sighting the North Star Polaris with a sextant and using sight reduction tables to correct for height of eye and atmospheric refraction; the height of Polaris in degrees above the horizon is the latitude of the observer, within a degree or so. Similar to latitude, the longitude of a place on Earth is the angular distance east or west of the prime meridian or Greenwich meridian. Longitude is expressed in degrees ranging from 0° at the Greenwich meridian to 180° east and west. Sydney, for example, has a longitude of about 151° east. New York City has a longitude of 74° west. For most of history, mariners struggled to determine longitude. Longitude can be calculated. Lacking that, one can use a sextant to take a lunar distance that, with a nautical almanac, can be used to calculate the time at zero longitude.
Reliable marine chronometers were unavailable until the late 18th century and not affordable until the 19th century. For about a hundred years, from about 1767 until about 1850, mariners lacking a chronometer used the method of lunar distances to determine Greenwich time to find their longitude. A mariner with a chronometer could check its reading using a lunar determination of Greenwich tim
A midshipman is an officer of the junior-most rank, in the Royal Navy, United States Navy, many Commonwealth navies. Commonwealth countries which use the rank include Canada, Bangladesh, New Zealand, South Africa, Pakistan, Sri Lanka, Kenya. In the 17th century, a midshipman was a rating for an experienced seaman, the word derives from the area aboard a ship, either where the original rating worked on the ship, or where he was berthed. Beginning in the 18th century, a commissioned officer candidate was rated as a midshipman, the seaman rating began to die out. By the Napoleonic era, a midshipman was an apprentice officer who had served at least three years as a volunteer, officer's servant or able seaman, was equivalent to a present-day petty officer in rank and responsibilities. After serving at least three years as a midshipman or master's mate, he was eligible to take the examination for lieutenant. Promotion to lieutenant was not automatic, many midshipmen took positions as master's mates for an increase in pay and responsibility aboard ship.
Midshipmen in the United States Navy were trained and served to midshipmen in the Royal Navy, although unlike their counterparts in the Royal Navy, a midshipman was a warrant officer rank until 1912. During the 19th century, changes in the training of naval officers in both the Royal Navy and the United States Navy led to the replacement of apprenticeship aboard ships with formal schooling in a naval college. Midshipman began to mean an officer cadet at a naval college. Trainees now spent around four years in a college and two years at sea prior to promotion to commissioned officer rank. Between the mid-19th and mid-20th centuries, time at sea declined to less than a year as the entry age was increased from 12 to 18. Ranks equivalent to midshipman exist in many other navies. Using US midshipman or pre-fleet board UK midshipman as the basis for comparison, the equivalent rank would be a naval cadet in training to become a junior commissioned officer. Using post-fleet board UK midshipman for comparison, the rank would be the most junior commissioned officer in the rank structure, similar to a US ensign in role and responsibility.
In many Romance languages, the literal translation of the local term for "midshipman" into English is "Navy Guard", including the French garde marine, Spanish guardia marina, Portuguese guarda-marinha, Italian guardiamarina. Today, these ranks all refer to naval cadets, but they were selected by the monarchy, were trained on land as soldiers; the rank of midshipman originated during the Tudor and Stuart eras, referred to a post for an experienced seaman promoted from the ordinary deck hands, who worked in between the main and mizzen masts and had more responsibility than an ordinary seaman, but was not a military officer or an officer in training. The first published use of the term midshipman was in 1662; the word derives from an area aboard a ship, but it refers either to the location where midshipmen worked on the ship, or the location where midshipmen were berthed. By the 18th century, four types of midshipman existed: midshipman, midshipman extraordinary and midshipman ordinary; some midshipmen were older men, while most were officer candidates who failed to pass the lieutenant examination or were passed over for promotion, some members of the original rating served, as late as 1822, alongside apprentice officers without themselves aspiring to a commission.
By 1794, all midshipmen were considered officer candidates, the original rating was phased out. Beginning in 1661, boys who aspired to become officers were sent by their families to serve on ships with a "letter of service" from the crown, were paid at the same rate as midshipmen; the letter instructed the admirals and captains that the bearer was to be shown "such kindness as you shall judge fit for a gentleman, both in accommodating him in your ship and in furthering his improvement". Their official rating was volunteer-per-order, but they were known as King's letter boys, to distinguish their higher social class from the original midshipman rating. Beginning in 1677, Royal Navy regulations for promotion to lieutenant required service as a midshipman, promotion to midshipman required some time at sea. By the Napoleonic era, the regulations required at least three years of services as a midshipman or master's mate and six years of total sea time. Sea time was earned in various ways, most boys served this period at sea in any lower rating, either as a servant of one of the ship's officers, a volunteer, or a seaman.
By the 1730s, the rating volunteer-per-order was phased out and replaced with a system where prospective midshipmen served as servants for officers. For example, a captain was allowed four servants for every 100 men aboard his ship. In 1729, the Royal Naval Academy in Portsmouth – renamed the Royal Naval College in 1806 – was founded, for 40 students aged between 13 and 16, who would take three years to complete a course of study defined in an illustrated book, would earn two years of sea time as part of their studies; the rating of midshipman-by-order, or midshipman ordinary, was used for graduates of the Royal Naval College, to distinguish them from midshipmen who had served aboard ship, who were paid more. The school was unpopular in the Navy, because officers enjoyed the privilege of having servants and preferred the traditional method of training officers via apprenticeship. In 1794, officers' servants were abolished and a new class of volunteers called'volunteer class I' was created for boys between the ag
Naval architecture, or naval engineering, along with automotive engineering and aerospace engineering, is an engineering discipline branch of vehicle engineering, incorporating elements of mechanical, electronic and safety engineering as applied to the engineering design process, shipbuilding and operation of marine vessels and structures. Naval architecture involves basic and applied research, development, design evaluation and calculations during all stages of the life of a marine vehicle. Preliminary design of the vessel, its detailed design, trials and maintenance, launching and dry-docking are the main activities involved. Ship design calculations are required for ships being modified. Naval architecture involves formulation of safety regulations and damage-control rules and the approval and certification of ship designs to meet statutory and non-statutory requirements; the word "vessel" includes every description of watercraft, including non-displacement craft, WIG craft and seaplanes, used or capable of being used as a means of transportation on water.
The principal elements of naval architecture are: Hydrostatics concerns the conditions to which the vessel is subjected while at rest in water and to its ability to remain afloat. This involves computing buoyancy and other hydrostatic properties such as trim and stability. Hydrodynamics concerns the flow of water around the ship's hull and stern, over bodies such as propeller blades or rudder, or through thruster tunnels. Resistance – resistance towards motion in water caused due to flow of water around the hull. Powering calculation is done based on this. Propulsion – to move the vessel through water using propellers, water jets, sails etc. Engine types are internal combustion; some vessels are electrically powered using solar energy. Ship motions – involves motions of the vessel in seaway and its responses in waves and wind. Controllability -- involves maintaining position and direction of the vessel. While atop a liquid surface a floating body has 6 degrees of freedom in its movements, these are categorized in either rotation or translation.
Fore and aft translation is termed surge. Transverse translation is termed sway. Vertical translation is termed heave. Rotation about a transverse axis is termed pitch. Rotation about a fore and aft axis is termed roll. Rotation about a vertical axis is termed yaw. Longitudinal stability for longitudinal inclinations, the stability depends upon the distance between the center of gravity and the longitudinal meta-center. In other words, the basis in which the ship maintains its center of gravity is its distance set apart from both the aft and forward section of the ship. While a body floats on a liquid surface it still encounters the force of gravity pushing down on it. In order to stay afloat and avoid sinking there is an opposed force acting against the body known as the hydrostatic pressures; the forces acting on the body must be of the same magnitude and same line of motion in order to maintain the body at equilibrium. This description of equilibrium is only present when a floating body is in still water, when other conditions are present the magnitude of which these forces shifts drastically creating the swaying motion of the body.
The buoyancy force is equal to the weight of the body, in other words, the mass of the body is equal to the mass of the water displaced by the body. This adds an upward force to the body by the amount of surface area times the area displaced in order to create an equilibrium between the surface of the body and the surface of the water; the stability of a ship under most conditions is able to overcome any form or restriction or resistance encountered in rough seas. Structures involves selection of material of construction, structural analysis of global and local strength of the vessel, vibration of the structural components and structural responses of the vessel during motions in seaway. Depending on the type of ship, the structure and design will vary in what material to use as well as how much of it; some ships are made from glass reinforced plastics but the vast majority are steel with some aluminium in the superstructure. The complete structure of the ship is designed with panels shaped in a rectangular form consisting of steel plating supported on four edges.
Combined in a large surface area the Grillages create the hull of the ship and bulkheads while still providing mutual support of the frames. Though the structure of the ship is sturdy enough to hold itself together the main force it has to overcome is longitudinal bending creating a strain against its hull, its structure must be designed so that the material is disposed as much forward and aft as possible; the principal longitudinal elements are the deck, shell plating, inner bottom all of which are in the form of grillages, additional longitudinal stretching to these. The dimensions of the ship are in order to create enough spacing between the stiffeners in prevention of buckling. Warships have used a longitudinal system of stiffening that many modern commercial vessels have adopted; this system was used in early merchant ships such as the SS Great Eastern, but shifted to transversely framed structure another concept in ship hull design that p
Captain (United States O-6)
In the United States Navy, United States Coast Guard, United States Public Health Service Commissioned Corps, National Oceanic and Atmospheric Administration Commissioned Officer Corps, captain is the senior-most commissioned officer rank below that of flag officer. The equivalent rank is colonel in the United States Army, Air Force, Marine Corps. Reflecting its nautical heritage, the term "captain" sometimes is used as a military title by more junior officers who are serving as the commanding officer of a commissioned vessel of the Navy, Coast Guard, or National Oceanic and Atmospheric Administration ship of patrol boat size or greater, while officers below O-6 commanding aviation squadrons will use the less formal title of "skipper". In the United States Navy, captain is a senior officer rank, with the pay grade of O-6, it ranks below rear admiral. It is equivalent to the rank of colonel in the other uniformed services. Promotion to captain is governed by Department of Defense policies derived from the Defense Officer Personnel Management Act of 1980 or its companion Reserve Officer Personnel Management Act.
DOPMA/ROPMA guidelines suggest that no more than 50% of eligible commanders should be promoted to captain after serving a minimum of three years at their present rank and after attaining 21–23 years of cumulative commissioned service, although this percentage may be appreciably less, contingent on force structure and the needs of the service. With few exceptions, such as Naval Aviator Astronaut and Naval Flight Officer Astronaut, unrestricted line officer captains in the Navy will have completed at least one commanding officer assignment at the commander level a destroyer or frigate for surface warfare officers, a nuclear-powered attack submarine or ballistic missile submarine for submarine warfare officers, a SEAL team for special warfare officers, or an aviation squadron for Naval Aviators and Naval Flight Officers, before being selected for promotion to captain. Navy captains with sea commands in the surface warfare officer community command ships of cruiser size or larger; the more senior the officer, the larger the ship.
Others may hold command as commodores of destroyer squadrons consisting of multiple destroyers and frigates. Surface Warfare Officers may command large deck amphibious warfare ships or combat support ships and serve as commodores of amphibious squadrons or other type of surface ship squadrons. In the submarine community, a captain commanded a nuclear-powered ballistic missile submarine until the early 21st century when the requisite rank for the position was downgraded to that of a commander. Today, like their surface warfare counterparts, captains in the submarine community may serve as commodores of submarine squadrons, commanding a group of SSBNs or attack submarines. In Naval Aviation, captains with sea commands are Naval Aviators or Naval Flight Officers who are commanding officers of aircraft carriers, commanding officers of large-deck air-capable amphibious assault ships, commanders of carrier air wings, or commodores of functional or "type" air wings or air groups. A smaller cohort outside of sea and shore commands may serve as astronauts on loan to the National Aeronautics and Space Administration.
In the Naval Special Warfare "Sea Air Land" community, captains with sea commands are commodores in command of Naval Special Warfare Groups. In contrast, commanders of aircraft carrier strike groups and expeditionary strike groups are rear admirals, while subordinate destroyer squadron commodores, amphibious squadron commodores, carrier air wing commanders and the individual ship commanding officers within the strike group are of captain rank or lower. In addition, in the expeditionary strike group, the Marine Expeditionary Unit commanding officer will always be a Marine Corps colonel. Adding to the confusion, all commanding officers of commissioned U. S. Navy warships and submarines are called "captain" regardless of actual rank. Navy captains who are line officers may fill senior command and staff positions ashore as Chiefs of Staff/Executive Assistants or senior operations officers to flag officers, or they may hold shore command assignments such as commanding officers of naval bases, naval stations, naval air stations, naval air facilities, naval support activities, logistics groups, specialized centers or schools, or commanders of test wings or training air wings.
They may occupy senior leadership positions on fleet staffs, naval component commands staffs, the staffs of the joint Unified Combatant Commands, the staff of the Chief of Naval Operations, or the Joint Staff. As opposed to unrestricted line captains, restricted line and staff corps captains will command facilities and organizations appropriate to their designators, such as intelligence centers commanded by intelligence officers; the United States Coast Guard uses the same naval rank system for its commissioned officers as the U. S. Navy, with a Coast Guard captain ranking