Rostock is a city in the north German state Mecklenburg-Vorpommern. Rostock is on the Warnow river. Rostock is the largest city in Mecklenburg-Vorpommern, as well as its only regiopolis. Rostock is home to one of the oldest universities in the world, the University of Rostock, founded in 1419; the city territory of Rostock stretches for about 20 km along the Warnow to the Baltic Sea. The largest built-up area of Rostock is on the western side of the river; the eastern part of its territory is dominated by the forested Rostock Heath. In the 11th century Polabian Slavs founded; the Danish king Valdemar I set the town on fire in 1161. Afterwards the place was settled by German traders. There were three separate cities: Altstadt around the Alter Markt, which had St. Petri, Mittelstadt around the Neuer Markt, with St. Marien and Neustadt around the Hopfenmarkt, with St. Jakobi. In 1218, Rostock was granted Lübeck law city rights by prince of Mecklenburg. During the first partition of Mecklenburg following the death of Henry Borwin II of Mecklenburg in 1226, Rostock became the seat of the Lordship of Rostock, which survived for a century.
In 1251, the city became a member of the Hanseatic League. In the 14th century it was a powerful seaport town with 12,000 inhabitants and the largest city in Mecklenburg. Ships for cruising the Baltic Sea were constructed in Rostock; the independent fishing village of Warnemünde at the Baltic Sea became a part of Rostock in 1323, to secure the city's access to the sea. In 1419, the University of Rostock was founded, the oldest university in continental northern Europe and the Baltic Sea area. At the end of the 15th century, the dukes of Mecklenburg succeeded in enforcing their rule over the town of Rostock, which had until been only nominally subject to their rule and independent, they took advantage of a riot known as a failed uprising of the impoverished population. Subsequent quarrels with the dukes and persistent plundering led to a loss of the city's economic and political power. In 1565 there were further clashes with Schwerin. Among other things, the nobility introduced a beer excise. John Albert I advanced on the city with 500 horsemen, after Rostock had refused to take the formal oath of allegiance, had the city wall razed in order to have a fortress built.
The conflict did not end until the first Rostock Inheritance Agreement of 21 September 1573, in which the state princes were guaranteed hereditary rule over the city for centuries and recognizing them as the supreme judicial authority. The citizens razed the fortress the following spring. From 1575 to 1577 the city walls were rebuilt, as was the Lagebusch tower and the Stein Gate, in the Dutch Renaissance style; the inscription sit intra te concordia et publica felicitas, can still be read on the gate, refers directly to the conflict with the Duke. In 1584 the Second Rostock Inheritance Agreement was enforced, which resulted in a further loss of former city tax privileges. At the same time, these inheritance contracts put paid to Rostock's ambition of achieving imperial immediacy, as Lübeck had done in 1226; the strategic location of Rostock provoked the envy of its rivals. Danes and Swedes occupied the city twice, first during the Thirty Years' War and again from 1700 to 1721. In the early 19th century, the French, under Napoleon, occupied the town for about a decade until 1813.
In nearby Lübeck-Ratekau, Gebhard Leberecht von Blücher, born in Rostock and, one of few generals to fight on after defeat at the Battle of Jena, surrendered to the French in 1806. This was only after furious street fighting in the Battle of Lübeck, in which he led some of the cavalry charges himself. By the time of the surrender, the exhausted Prussians had neither ammunition. In the first half of the 19th century, Rostock regained much of its economic importance, due at first to the wheat trade from the 1850s, to industry its shipyards; the first propeller-driven steamers in Germany were constructed here. The city grew in area and population, with new quarters developing in the south and west of the ancient borders of the city. Two notable developments were added to house the increasing population at around 1900: Steintor-Vorstadt in the south, stretching from the old city wall to the facilities of the new Lloydbahnhof, was designed as a living quarter, it consisted of large single houses, once inhabited by wealthy citizens.
Kröpeliner-Tor-Vorstadt in the west, was designed to house the working population as well as to provide smaller and larger industrial facilities, such as the Mahn & Ohlerich's Brewery. The main shipyard, was nearby at the shore of the river. In the 20th century, important aircraft manufacturing facilities were situated in the city, such as the Arado Flugzeugwerke in Warnemünde and the Heinkel Works with facilities at various places, including their secondary Heinkel-Süd facility in Schwechat, Austria, as the original Heinkel firm's Rostock facilities had been renamed Heinkel-
A buoy is a floating device that can have many purposes. It can be allowed to drift with ocean currents; the etymology of the word is disputed. Buoy racing is the most prevalent form of yacht racing Emergency wreck buoy – An Emergency Wreck Buoys provides a clear and unambiguous means of marking new wrecks; this buoy is used as a temporary response for the first 24–72 hours. This buoy is coloured in an equal number of blue and yellow vertical stripes and is fitted with an alternating blue and yellow flashing light; this has come about due to the collisions which occurred in the Dover Straits in 2002 when vessels struck the new wreck of the MV Tricolor. Ice marking buoys – used for marking ice holes in frozen lakes and rivers, so that snowmobiles do not drive over the holes. Large Navigational Buoy is an automatic buoy over 10m high equipped with a powerful light monitored electronically as a replacement for lightships. A LNB may be marked on charts as a "Superbuoy." Lobster trap buoys – brightly colored buoys used for the marking of lobster trap locations so the person lobster fishing can find their lobster traps.
Each lobster fisherman has his or her own color markings or registration numbers so they know which ones are theirs. They are only allowed to haul their own traps and must display their buoy color or license number on their boat so law enforcement officials know what they should be hauling; the buoys are brightly colored with visible numbers so they can be seen under conditions when there is poor visibility like rain, sea smoke, etc. lateral marker buoy Safe water mark or Fairway Buoy – a navigational buoy which marks the entrance to a channel or a nearby landfall Sea mark – aids pilotage by marking a maritime channel and administrative area to allow boats and ships to navigate safely. Some navigational buoys are fitted with a bell or gong, which sounds when waves move the buoy Wreck buoy – a buoy to mark a wrecked ship to warn other ships to keep away because of unseen hazards. Lifebuoy – used as a life saving buoy designed to be thrown to a person in the water to provide buoyancy. Has a connecting line allowing the casualty to be pulled to the rescuer Self-locating datum marker buoy – A 70% scale Coastal Ocean Dynamics Experiment /Davis-style oceanographic surface drifter with drogue vanes between 30 and 100 cm deep.
This particular surface drifter is designed for deployment from a U. S. Coast Guard vessel or airframe for search and rescue. Since the SLDMB has a small surface area above the ocean surface and a high underwater surface area, there is little leeway in response to the direct forcing of winds and waves. Submarine rescue buoy – used for release in case of emergencies or for communication Decompression buoy – deployed by submerged scuba divers to mark their position underwater whilst doing decompression stops Shot buoy – used to mark dive sites for the boat safety cover of scuba divers so that the divers can descend to the dive site more in conditions of low visibility or tidal currents and more safely do decompression stops on their ascent. Surface marker buoy – taken on dives by scuba divers to mark their position underwater Profiling buoy – specialized models which adjust buoyancy so that they will sink at a controlled rate to 2,000 metres below the surface while measuring sea temperatures and salinity.
After a time 10 days, the buoy returns to the surface, transmits its data via satellite, sinks again. See Argo. Tsunami buoys – anchored buoys that can detect sudden changes in undersea water pressure are used as part of tsunami warning systems in the Pacific Tsunami Warning Center and Indian Oceans. Wave buoy – used to measure the movement of the water surface as a wave train; the wave train is analysed to determine statistics like the significant wave height and period, wave direction. Weather buoys – equipped to measure weather parameters such as air temperature, barometric pressure, wind speed and direction and to report these data via satellite radio links such as the purpose-built Argos System or commercial satellite phone networks to meteorological centres for use in forecasting and climate study. May be allowed to drift in the open ocean currents. Position is calculated by the satellite. Weather buoys are sometimes referred to as ODAS buoys or Ocean Data Acquisition Systems and may be marked on charts as "Superbuoys."
Mooring buoys – used to keep one end of a mooring cable or chain on the water's surface so that ships or boats can tie on to it. Many marinas mark these with a number and assign it to a particular vessel, or rent it out to transient vessels. Tripping buoys – used to keep one end of a'tripping line' on the water's surface so that a stuck anchor can more be freed Marker buoys – used in naval warfare anti-submarine warfare, is a light-emitting or smoke-emitting, or both, marker using some kind of pyrotechnic to provide the flare and smoke, it is a 3-inch diameter device about 20 inches long, set off by contact with seawater and floats on the surface. Some markers extinguish after others are made to sink. Sonobuoy – used by anti-submarine warfare aircraft to detect submarines by SONAR Target buoy – used to simulate target in live fire exercise by naval and coastal forces targeted by weapons like HMG's, rapid fire cannons and anti-tank rockets. DAN buoy – has several meanings: A large maritime navigational aid providing a platform for light and radio beacons A lifebuoy with flags used on yachts and smaller pl
A berth is a designated location in a port or harbour used for mooring vessels when they are not at sea. Berths provide a vertical front which allows safe and secure mooring that can facilitate the unloading or loading of cargo or people from vessels. Berth is the term used in ports and harbors for a designated location where a vessel may be moored for the purposes of loading and unloading. Berths are designated by the management of a facility. Vessels are assigned to berths by these authorities. Most berths are alongside a jetty or a floating dock. Berths are either specific to the types of vessel that use them; the size of the berths varies from 5–10 m for a small boat in a marina to over 400 m for the largest tankers. The rule of thumb is that the length of a berth should be 10% longer than the longest vessel to be moored at the berth; the following is a list of berth types based on the method of construction: Solid Structure Berth In these berths, a solid vertical structure is created to contain fill material, brought all the way to the structure.
They can be constructed using either a gravity wall structure where the front wall of the structure uses its own weight and friction to contain the fill or with a sheet pile structure where an anchoring plate is used to contain the weight of the fill dirt. Open Structure Berth Open berths feature structures supported by piles set off shore from the natural extent of the land or the farthest extent of fill dirt; this style of berth can offer more flexibility in the specificity of construction but presents more complicated dredging projects afterwards and limits the amount of weight the berth is able to support and resist. The following is a list of berth types based on the method of geometry: Finger Pier Used to maximize the berthing space per length of waterfront. Finger piers are used for small to medium vessels associated with passenger travel. Finger piers can be used for dangerous cargoes such as military Equipment that can not be used with offshore berths because of the weight and equipment requirements.
In these instances long finger piers allow for far reach far off shore with access for rail or other cargo moving methods on the pier. Offshore Berth Used. Offshore berths are created for berthing of oil and gas vessels, they contain stand alone structures called dolphins which have fenders and bollards located to based on the geometry of the vessels which would call the berth. The following is a list of berth types based on cargo of the ships calling: Bulk Berth Used to handle either dry or liquid bulk cargo. Vessels are loaded using conveyor belts, and/or pipelines. Storage facilities for the bulk cargo are alongside the berth – e.g. silos or stockpiles. Container Berth Used to handle standard intermodal containers. Vessels are loaded and unloaded by container cranes, designed for the task; these berths will feature large areas of land for container handling near the berth and will have significant equipment on dock to facilitate rapid movement of containers on and off the vessels. Alongside the quay there is a large flat area used to store both the imported and exported containers.
General Berth Used to handle smaller shipments of general cargo. Vessels using these would have their own lifting gear, but some ports will provide mobile cranes to do this; these are common at smaller ports where special project cargo is common. Lay Berth A berth used for idle vessels. Vessels being put on the hook can use these as intermediate points between operational use and mothballing at an off shore mooring; these berths will feature little land side access or equipment except what is needed to secure the vessel. Lay-by Berth A general berth for use by vessels for short term waiting until a loading or discharging berth is available; these berths can feature basic amenities for fuel and utilities to sustain a crew and vessel until the destination berth is available. Liquid Berth Used to handle gas related products. Berths are placed offshore to keep safe zone of operation from rest of port operations. Vessels are loaded via loading arms containing the pipe lines. Cargo is the pumped back on shore through pipelines, which are submerged.
Storage facilities for the products are some distance away from the berth and connected by these pipelines. Marina Berth Used to allow the owners of leisure craft off their boats. Alongside pontoons and accessed by hinged bridges to the shore. Marina berths are built with modular capabilities to adjust the berth size for various shapes and sizes of recreational craft. Specialized equipment for keeping boats out of the water is a frequent feature; this allows the vessel to be removed from the negative effects of wave action on the hull and helps prevent organic growth on the hull. Z Berth Suitable for nuclear-powered warships, part of an operational Naval base or a building and refitting yard. All X-berths have as an integral part of their safety arrangements a permanent health physics department, a local emergency monitoring organisation and a local safety plan prepared under the auspices of a local liaison committee
A dock is the area of water between or next to one or a group of human-made structures that are involved in the handling of boats or ships or such structures themselves. The exact meaning varies among different variants of the English language. "Dock" may refer to a dockyard where the loading, building, or repairing of ships occurs. The earliest known docks were those discovered in Wadi al-Jarf, an ancient Egyptian harbor dating from 2500 BCE located on the Red Sea coast. Archaeologists discovered anchors and storage jars near the site. A dock from Lothal in India dates from 2400 BCE and was located away from the main current to avoid deposition of silt. Modern oceanographers have observed that the ancient Harappans must have possessed great knowledge relating to tides in order to build such a dock on the ever-shifting course of the Sabarmati, as well as exemplary hydrography and maritime engineering; this is the earliest known dock found in the world equipped to service ships. It is speculated that Lothal engineers studied tidal movements and their effects on brick-built structures, since the walls are of kiln-burnt bricks.
This knowledge enabled them to select Lothal's location in the first place, as the Gulf of Khambhat has the highest tidal amplitude and ships can be sluiced through flow tides in the river estuary. The engineers built a trapezoidal structure, with north-south arms of average 21.8 metres, east-west arms of 37 metres. In British English, a dock is an enclosed area of water used for loading, building or repairing ships; such a dock may be created by building enclosing harbour walls into an existing natural water space, or by excavation within what would otherwise be dry land. There are specific types of dock structures where the water level is controlled: A wet dock or impounded dock is a variant in which the water is impounded either by dock gates or by a lock, thus allowing ships to remain afloat at low tide in places with high tidal ranges; the level of water in the dock is maintained despite the falling of the tide. This makes transfer of cargo easier, it works like a lock which allows passage of ships.
The world's first enclosed wet dock with lock gates to maintain a constant water level irrespective of tidal conditions was the Howland Great Dock on the River Thames, built in 1703. The dock was a haven surrounded by trees, with no unloading facilities; the world's first commercial enclosed wet dock, with quays and unloading warehouses, was the Old Dock at Liverpool, built in 1715 and held up to 100 ships. The dock reduced ship waiting giving quick turn arounds improving the throughput of cargo. A drydock is another variant with dock gates, which can be emptied of water to allow investigation and maintenance of the underwater parts of ships. A floating dry dock is a submersible structure which lifts ships out of the water to allow dry docking where no land-based facilities are available. Where the water level is not controlled berths may be: Floating, where there is always sufficient water to float the ship. NAABSA where ships settle on the bottom at low tide. Ships using NAABSA facilities have to be designed for them.
A dockyard consists of one or more docks with other structures. In American English, a dock is technically synonymous with pier or wharf—any human-made structure in the water intended for people to be on. However, in modern use, pier is used to refer to structures intended for industrial use, such as seafood processing or shipping, more for cruise ships, dock is used for most everything else with a qualifier, such as ferry dock, swimming dock, ore dock and others. However, pier is commonly used to refer to wooden or metal structures that extend into the ocean from beaches and are used, for the most part, to accommodate fishing in the ocean without using a boat. In American English, the term for the water area between piers is "slip". In the cottage country of Canada and the United States, a dock is a wooden platform built over water, with one end secured to the shore; the platform is used for the offloading of small boats. Dry dock: a narrow basin that can be flooded and drained to allow a load to come to rest on a dry platform Ferry slip: a specialized docking facility that receives a ferryboat Floating dock Floating dock: a walkway over water, made buoyant with pontoons Harbor Jetty Marina Mole Pier: a raised walkway over water, supported by spread pilings or pillars Pontoon: a buoyant device, used to support docks or floating bridges Quay Slipway: a ramp on the shore by which ships or boats can be moved to and from the water Wharf: a fixed platform on pilings, where ships are loaded and unloaded Rao, S. R..
Lothal, a Harappan Port Town. New Delhi: Archaeological Survey of India. OCLC 60370124. Encyclopædia Britannica, "dry-dock"
A yacht club is a sports club related to yachting. Yacht clubs are located by the sea, although there are some that have been established at a lake or riverside locations. Yacht or sailing clubs have either a marina or a delimited section of the beach or shoreline with buoys marking the areas off-limits for swimmers as well as safe offshore anchorages. On shore they include a perimeter reserved for the exclusive use of the members of the club as well as a clubhouse with attached bar, café or restaurant where members socialize in a pleasant and informal setting. Although the terms Yacht Club and Sailing Club tend to be synonymous, some general differences regarding the recreational use of boats can be broadly outlined. A Yacht Club tended to focus on a membership composed of yacht owners, including motorboats; this type of club was exclusive, attracting the aristocracy or the high class and leaving small boat owners out of the circle. On the other hand, a Sailing Club tended to focus on a membership composed of owners of sailboats, including smaller boats such as dinghies.
These became popular towards the end of the 19th century when small boats began to be produced on an industrial scale. Yacht clubs are known by their initials. Many well known yacht clubs, including the Yacht Club de France and the Royal Yacht Squadron, have been established under royal patronage or have been granted the title at some point in their history. Organized and run by the membership, Yacht Clubs became a place to promote the sport of sailboat racing and cruising, as well as provide a meeting place for the particular social community; the membership is a mixture of people with specific recreational affinities, the members include those who sail as crew for cruising or racing, as well as boat owners. It is up to the members decide on the objectives of the club to satisfy the membership and to attract other like-minded individuals. For example, some clubs include owners of powerboats, while others exclude them. In order to overcome difficulties concerning the affinities of their members one particular club may have two sections, a sailing section and a powerboat section.
Members Clubs have paid staff for catering, bar duty, boat yard duty, office etc. Control and organization of the club is done for the membership via members elected by the membership into roles such as Sailing Secretary, Cruising Captain, Racing Captain etc. Smaller clubs have a condition of membership which requires active participation of the membership in activities such as maintenance of club facilities and equipment. Unlike the classical clubs where the membership is the focus, certain'clubs' are run on a commercial basis, they may be owned by a company to provide a service and generate a profit. They are associated with a particular marina or port. Objectives are broadly similar to members clubs, but the social side may be more dominant. There is a long historical tradition behind yacht clubs. According to the date of establishment, the Neva Yacht Club, founded in 1718 in Russia, is the oldest yacht club. However, since this Russian Yacht Club was established by a decree of Tsar Peter the Great, it does not qualify as a proper club in the modern sense, understood as a voluntary association of members who organize and run the club.
Therefore, the Royal Cork Yacht Club founded in Ireland in 1720 is widely acknowledged as the oldest yacht club in the world, despite having gone through periods of dormancy and undergone name changes in its long history, much in the same manner as the Neva Yacht Club. It was only in 1846 that the first yacht club in Russia to adopt British-style Members Club regulations was established. Using this Western understanding of what a club or society is, the Royal Swedish Yacht Club, KSSS, founded 1830, becomes the oldest European yacht club outside the British Isles, the fifth oldest in the world. A number of the world's most renowned Yacht Clubs are located in the United Kingdom, Germany and the United States; the first yacht club in North America was the Royal Nova Scotia Yacht Squadron, located on the Northwest Arm in Halifax, Nova Scotia, Canada established in July 1837. Some yacht clubs are affiliated with an international body, the International Council of Yacht Clubs, which exists to improve the quality of the services yacht clubs provide to their members as well as to promote environmental awareness and responsibility towards the environment.
The Kieler Yacht-Club in Northern Germany organizes the yearly Kiel Week, the biggest sailing event in the world, celebrated since 1882. Most clubs, regardless of the size of their craft, have a well defined racing program. Clubs may host regattas ranging from informal local events to national championships. Clubs have a regular weekday evening racing schedule or a weekend racing schedule organized by the membership. Many yacht clubs field teams to compete against other clubs in team racing. There are some specific boat models and lengths which have their own club; these boat ownership clubs hold single design races for their members. With the growth of sailing at secondary schools and universities many yacht clubs host Interscholastic Sailing Association or Intercollegiate Sailing Association regattas. Additionally, a number of yacht clubs enter into agreements with schools to provide dock space and practice facilities for the school teams year-round. Clubs with active adult sailing programs most feature junior sailing programs as well.
Most these programs enroll children from ages 8 to 16. Children
A trailer is an unpowered vehicle towed by a powered vehicle. It is used for the transport of goods and materials. Sometimes recreational vehicles, travel trailers, or mobile homes with limited living facilities where people can camp or stay have been referred to as trailers. In earlier days, many such vehicles were towable trailers. In the United States, the term is sometimes used interchangeably with travel trailer and mobile home, varieties of trailers and manufactured housing designed for human habitation, their origins lay in utility trailers built in a similar fashion to horse-drawn wagons. A trailer park is an area. In the United States trailers ranging in size from single-axle dollies to 6-axle, 13-foot-6-inch high, 53-foot long semi-trailers are commonplace; the latter, when towed as part of a tractor-trailer or "18-wheeler", carries a large percentage of the freight that travels over land in North America. Some trailers are made for personal use with any powered vehicle having an appropriate hitch, but some trailers are part of large trucks called semi-trailer trucks for transportation of cargo.
Enclosed toy trailers and motorcycle trailers can be towed by accessible pickup truck or van, which require no special permit beyond a regular driver's license. Specialized trailers like open-air motorcycle trailers, bicycle trailers are much smaller, accessible to small automobiles, as are some simple trailers, pulled by a drawbar and riding on a single set of axles. Other trailers, such as utility trailers and travel trailers or campers come in single and multiple axle varieties, to allow for varying sizes of tow vehicles. There exist specialized trailers, such as genset trailers, pusher trailers and their ilk that are used to power the towing vehicle. Others are custom-built to hold entire kitchens and other specialized equipment used by carnival vendors. There are trailers for hauling boats. Popular campers use lightweight trailers, aerodynamic trailers that can be towed by a small car, such as the BMW Air Camper, they are built to be lower than the tow vehicle. Others range from two-axle campers that can be pulled by most mid-sized pickups to trailers that are as long as the host country's law allows for drivers without special permits.
Larger campers tend to be integrated recreational vehicles, which are used to tow single-axle dolly trailers to allow the users to bring small cars on their travels. A semi-trailer is a trailer without a front axle. A large proportion of its weight is supported either by a road tractor or by a detachable front axle assembly known as a dolly. A semi-trailer is equipped with legs, called "landing gear", which can be lowered to support it when it is uncoupled. In the United States, a single trailer cannot exceed a length of 57 ft 0 in on interstate highways, although it is possible to link two smaller trailers together to a maximum length of 63 ft 0 in. Semi-trailers vary in design, ranging from open-topped grain haulers through Tautliners to normal-looking but refrigerated 13 ft 6 in x 53 ft 0 in enclosures. Many semi-trailers are part of semi-trailer trucks. Other types of semi-trailers include dry vans and chassis. Many commercial organizations choose to rent or lease semi-trailer equipment rather than own their own semi-trailers, to free up capital and to keep trailer debt from appearing on their balance sheet.
A full trailer is a term used in the United States for a freight trailer supported by front and rear axles and pulled by a drawbar. In Europe this is known as an A-frame drawbar trailer. A commercial friegt trailer is 102 in wide and 35 or 40 ft long; as per AIS 053, full trailer is a towed vehicle having at least two axles, equipped with a towing device which can move vertically in relation to the trailer and controls the direction of the front axle, but which transmits no significant static load to the towing vehicle. This style of trailer is popular for use with farm tractors. A close-coupled trailer is fitted with a rigid towbar which projects from its front and hooks onto a hook on the tractor, it does not pivot. A motorcycle trailer may be a trailer designed to haul motorcycles behind an truck; such trailers may be open or enclosed, ranging in size from trailers capable of carrying several motorcycles or only one. They may be designed to carry motorcycles, with ramps and tie-downs, or may be a utility trailer adapted permanently or to haul one or more motorcycles.
Another type of motorcycle trailer is a wheeled frame with a hitch system designed for transporting cargo by motorcycle. Motorcycle trailers are narrow and styled to match the appearance of the motorcycle they are intended to be towed behind. There are single-wheeled versions. Single-wheeled trailers, such as the Unigo or Pav 40/41, are designed to allow the bike to have all the normal flexibility of a motorcycle using a universal joint to enable the trailer to lean and turn with the motorcycle. No motorcycle manufacturer recommends that its motorcycles be used to tow a trailer because it creates additional safety hazards for motorcyclists. There is a number of different styles of trailers used to haul livestock such as horses; the most common is the stock trailer, a trailer, enclosed on the bottom, but has openings at the eye level of the animals to allow ventilation. The horse trailer is a more elaborate form of stock trailer; because horses are hauled for the purpose of competition or work, where
Lock (water navigation)
A lock is a device used for raising and lowering boats and other watercraft between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber. Locks are used to make a river more navigable, or to allow a canal to cross land, not level. Canals used more and larger locks to allow a more direct route to be taken. Since 2016, the largest lock worldwide is the Kieldrecht Lock in the Port of Belgium. A pound lock is a type of lock, used exclusively nowadays on canals and rivers. A pound lock has a chamber with gates at both ends. In contrast, an earlier design with a single gate was known as a flash lock. Pound locks were first used in medieval China during the Song Dynasty, having been pioneered by the Song politician and naval engineer Qiao Weiyue in 984, they replaced earlier double slipways that had caused trouble and are mentioned by the Chinese polymath Shen Kuo in his book Dream Pool Essays, described in the Chinese historical text Song Shi: The distance between the two locks was rather more than 50 paces, the whole space was covered with a great roof like a shed.
The gates were'hanging gates'. The water level could differ by 4 feet or 5 feet at each lock and in the Grand Canal the level was raised in this way by 138 feet. In medieval Europe a sort of pound lock was built in 1373 at Netherlands; this pound lock serviced many ships at once in a large basin. Yet the first true pound lock was built in 1396 at Damme near Belgium; the Italian Bertola da Novate constructed 18 pound locks on the Naviglio di Bereguardo between 1452 and 1458. When a stretch of river is made navigable, a lock is sometimes required to bypass an obstruction such as a rapid, dam, or mill weir – because of the change in river level across the obstacle. In large scale river navigation improvements and locks are used together. A weir will increase the depth of a shallow stretch, the required lock will either be built in a gap in the weir, or at the downstream end of an artificial cut which bypasses the weir and a shallow stretch of river below it. A river improved by these means is called a Waterway or River Navigation.
Sometimes a river is made non-tidal by constructing a sea lock directly into the estuary. In more advanced river navigations, more locks are required. Where a longer cut bypasses a circuitous stretch of river, the upstream end of the cut will be protected by a flood lock; the longer the cut, the greater the difference in river level between start and end of the cut, so that a long cut will need additional locks along its length. At this point, the cut is, in effect, a canal. Early artificial canals, across flat countryside, would get round a small hill or depression by detouring around it; as engineers became more ambitious in the types of country they felt they could overcome, locks became essential to effect the necessary changes in water level without detours that would be uneconomic both in building costs and journey time. Still, as construction techniques improved, engineers became more willing to cut directly through and across obstacles by constructing long tunnels, aqueducts or embankments, or to construct more technical devices such as inclined planes or boat lifts.
However, locks continued to be built to supplement these solutions, are an essential part of the most modern navigable waterways. All pound locks have three elements: A watertight chamber connecting the upper and lower canals, large enough to enclose one or more boats; the position of the chamber is fixed. A gate at each end of the chamber. A gate is opened to allow a boat to leave the chamber. A set of lock gear to fill the chamber as required; this is a simple valve which allows water to drain into or out of the chamber. The principle of operating a lock is simple. For instance, if a boat travelling downstream finds the lock full of water: The entrance gates are opened and the boat moves in; the entrance gates are closed. A valve is opened, this lowers the boat by draining water from the chamber; the exit gates are opened and the boat moves out. If the lock were empty, the boat would have had to wait 5 to 10 minutes. For a boat travelling upstream, the process is reversed; the whole operation will take between 10 and 20 minutes, depending on the size of the lock and whether the water in the lock was set at the boat's level.
Boaters approaching a lock are pleased to meet another boat coming towards them, because this boat will have just exited the lock on their level and therefore set the lock in their favour – saving about 5 to 10 minutes. However, this is not true for staircase locks, where it is quicker for boats to go through