San Francisco Bay is a shallow estuary in the US state of California. It is surrounded by a contiguous region known as the San Francisco Bay Area, is dominated by the large cities of San Jose, San Francisco and Oakland. San Francisco Bay drains water from 40 percent of California. Water from the Sacramento and San Joaquin rivers, from the Sierra Nevada mountains, flow into Suisun Bay, which travels through the Carquinez Strait to meet with the Napa River at the entrance to San Pablo Bay, which connects at its south end to San Francisco Bay, it connects to the Pacific Ocean via the Golden Gate strait. However, this entire group of interconnected bays is called the San Francisco Bay; the bay was designated a Ramsar Wetland of International Importance on February 2, 2012. The bay covers somewhere between 400 and 1,600 square miles, depending on which sub-bays, wetlands, so on are included in the measurement; the main part of the bay measures three to twelve miles wide east-to-west and somewhere between 48 miles 1 and 60 miles 2 north-to-south.

It is the largest Pacific estuary in the Americas. The bay was navigable as far south as San Jose until the 1850s, when hydraulic mining released massive amounts of sediment from the rivers that settled in those parts of the bay that had little or no current. Wetlands and inlets were deliberately filled in, reducing the Bay's size since the mid-19th century by as much as one third. Large areas of wetlands have been restored, further confusing the issue of the Bay's size. Despite its value as a waterway and harbor, many thousands of acres of marshy wetlands at the edges of the bay were, for many years, considered wasted space; as a result, soil excavated for building projects or dredged from channels was dumped onto the wetlands and other parts of the bay as landfill. From the mid-19th century through the late 20th century, more than a third of the original bay was filled and built on; the deep, damp soil in these areas is subject to soil liquefaction during earthquakes, most of the major damage close to the Bay in the Loma Prieta earthquake of 1989 occurred to structures on these areas.

The Marina District of San Francisco, hard hit by the 1989 earthquake, was built on fill, placed there for the Panama-Pacific International Exposition, although liquefaction did not occur on a large scale. In the 1990s, San Francisco International Airport proposed filling in hundreds more acres to extend its overcrowded international runways in exchange for purchasing other parts of the bay and converting them back to wetlands; the idea was, remains, controversial. There are five large islands in San Francisco Bay. Alameda, the largest island, was created when a shipping lane was cut to form the Port of Oakland in 1901, it is now a suburban community. Angel Island was known as "Ellis Island West" because it served as the entry point for immigrants from East Asia, it is now a state park accessible by ferry. Mountainous Yerba Buena Island is pierced by a tunnel linking the east and west spans of the San Francisco–Oakland Bay Bridge. Attached to the north is the artificial and flat Treasure Island, site of the 1939 Golden Gate International Exposition.

From the Second World War until the 1990s, both islands served as military bases and are now being redeveloped. Isolated in the center of the Bay is Alcatraz, the site of the famous federal penitentiary; the federal prison on Alcatraz Island no longer functions, but the complex is a popular tourist site. Despite its name, Mare Island in the northern part of the bay is a peninsula rather than an island. San Francisco Bay is thought to represent a down-warping of the Earth's crust between the San Andreas Fault to the west and the Hayward Fault to the east, though the precise nature of this remains under study. About 560,000 years ago, a tectonic shift caused the large inland Lake Corcoran to spill out the central valley and through the Carquinez Strait, carving out sediment and forming canyons in what is now the northern part of the San Francisco Bay and Golden Gate strait; until the last ice age, the basin, now filled by the San Francisco Bay was a large linear valley with small hills, similar to most of the valleys of the Coast Ranges.

As the great ice sheets began to melt, around 11,000 years ago, the sea level started to rise. By 5000 BC the sea level rose 300 feet; the valley become a bay, the small hills became islands. From 15,000 – 10,000 years ago, the Ohlone tribe inhabited the area, now the San Francisco Bay; the natives were displaced 5,000 years ago as the bay filled with water due to the rising sea level at the end of the ice age. The first European to see San Francisco Bay is N. de Morena, left at New Albion at Drakes Bay in Marin County, California by Sir Francis Drake in 1579 and walked to Mexico. The first recorded European discovery of San Francisco Bay was on November 4, 1769 when Spanish explorer Gaspar de Portolà, unable to find the port of Monterey, continued north close to what is now Pacifica and reached the summit of the 1,200-foot-high Sweeney Ridge, now marked as the place where he first sighted San Francisco Bay. Portolá and his party did not realize what they had discovered, thinking they had arrived at a large arm of what is now called Drakes Bay.

At the time, Drakes Bay went by the name Bahia de San Francisco and thus both bodies of water became associated with the name. The larger, more important body of water appropriated the name San Francisco Bay; the first European to enter the bay is believed to hav

A monohull is a type of boat having only one hull, unlike multihulled boats which can have two or more individual hulls connected to one another. Among the earliest hulls were simple logs, but these were unstable and tended to roll over easily. Hollowing out the logs into a dugout canoe doesn't help much unless the hollow section penetrates below the log's center of buoyancy a load carried low in the cavity stabilizes the craft. Adding weight or ballast to the bottom of the hull or as low as possible within the hull adds stability. Naval architects place the center of gravity below the center of buoyancy; the use of stones and other weights as ballast can be traced back to the Romans and Vikings. Modern ships carry tons of ballast; this is the most prevalent form of waterborne vessel. Keels - Most sailing ships and larger sailboats have deep keels containing ballast which adds horizontal stabilility. Displacement hulls - Monohull boats ride in the water, this is known as a displacement hull. Planing hulls - Hulls that ride on top of the water are called planing hulls, because when they reach speed, the hulls are lifted above the water.

Jim Howard, Charles J. Doane. Handbook of offshore cruising: The Dream and Reality of Modern Ocean Cruising. Sheridan House, Inc. p. 280. ISBN 1-57409-093-3. C. A. Marchaj. Aero-Hydrodynamics of Sailing. Tiller Publishing. ISBN 1-888671-18-1. C. A. Marchaj. Sail Performance. McGraw Hill. P. 400. ISBN 0-07-141310-3. C. A. Marchaj. Seaworthiness:The Forgotten Factor. Tiller Publishing. P. 372. ISBN 1-888671-09-2. Sailing Yachts Sailboats Multihull Keel Displacement Displacement hull Hydrodynamics Buoyancy Catamaran

Domesticated animals in the Philippines include pigs, water buffalo, goats and dogs. Domestication is when a species is selectively bred to produce certain traits that are seen as desirable; some desirable traits include quicker growth and maturity, increased fertility, adaptability to various conditions, living in herds. Domesticated animals play an important socioeconomic role in the Philippines, as seen through their widespread use in rituals. There is evidence for pigs in the Philippines during the Iron Age. Pig remains were found at the Nagsabaran site in Alaguia, Lal-lo town in Cagayan Province, Northern Luzon. Of the pig remains, two different taxa were found: an unknown species; the unknown species’ remains are similar to Sus Scrofa, a domesticated pig found in Luzon. Through morphometric examination of teeth, researchers concluded that the unknown species of pig was domesticated due to its larger size than the Philippine warty pig and its similarity to the domesticated species Sus scrofa.

A carbon-14 date on a premolar of the unknown species dates domesticated pigs at ca. 2500-2200 cal BC. Faunal remains of predominantly wild pig were found at the Nagsabaran site, indicating that hunting was the primary subsistence strategy during the Neolithic and Iron Age and pigs were not domesticated for the sole purpose of subsistence. In present-day villages located in Luzon and Palawan, domesticated pigs are only eaten for ceremonial purposes, while wild pigs are never used for rituals. In Borneo, indigenous groups use pigs for trade and social status. Throughout the Philippines, domesticated pigs are bred for socioeconomic reasons and are used for ceremonies, bride wealth and ritual feasting. Domesticated pigs are used to make and strengthen alliances, they are used as deity offerings. Goats were believed to be introduced into the Philippines as cargo from Islamic or early traders and established into domestic contexts by Spanish contact before the fifteenth century A. D. Goats had a variety of uses throughout the Philippines, some examples of places where goats were used include.

Goats were a part of ritual feasts in chiefly societies. There is evidence that goats were consumed in Moros, where as in the Visayas, humans did not eat goat or consume their milk products. After Spanish contact, there was an increase of use in goats for food. In Mindanao, it was common for goats to be used as trade; the first animal to be domesticated in the Philippines was the dog, Canis familiaris. The arrival of dogs in the Philippines were brought by some of the earliest colonists coming into the Philippine Archipelago. There have been a differential treatment of dogs within each community in the Philippines. In Nagsabaran, a site in Cagayan, Northern Luzon Philippines, there is archaeological evidence for multiple uses of dog in Philippine societies. In one pit, found within the same stratigraphic area as humans, there is evidence of butchery due to the numerous cut marks on remains. In proper and deliberate dog burials, there is evidence of humans having an emotional tie or a special relation relationship to this animal because of their important use in the Philippine society.

These dogs served as a utilitarian purpose and were used as a guard, for hunting, or for any other utilitarian purpose. In other cases, dogs were bred as consumption for marriages, or any other celebrations. Fish were an important in the Philippine economy and an important resource to rituals in prehispanic Philippine societies; the main sources of fish in the Philippines came from three major habitats. For each of these waters: Fresh water: hook and line, nets, or speared Marine inshore waters: hook and line, netting, or spearing Marine offshore waters: caught using ancient fishing gear, a paddled or sailed dugout, fish corrals, spears, or hooks and linesSome of the many fish that were caught include catfish, snappers, sharks, parrotfish, yellow fish tuna, mackerel. In some villages, fishing was reserved for markets due to orders from chiefs. In the Boxer's Codex, it explains how helmets were made using fish skins. Fish were used as a sacrifice during rituals that involved pig slaughtering. In Manila, there is evidence of Tagalogs having used fish as sacrifices to anito spirits.

One of the largest wild animals available for exploitation in the Philippines. In lowland populations, deer were not involved in trading, rituals, or feasting up until after the seventeenth century A. D. For example, deer skin was used as a trading product between the Japanese. In the Visayas, there is evidence of deer being eating during special occasions. In Nagsabaran, deer was the second most amount of mammal faunal found on the site; the variety of teeth found indicates. Deer bones the lower limb portions, were used to manufacture tools using a groove and snap technique. Deer faunal assemblages were higher in lower populations because they tended to withdraw from populated environments. One of the few animals the Austronesian speaking people brought with them on their journey to Southeast Asia. Water-buffalo is credited with the success of wet rice cultivation. Unlike cattle, their hooves allow them to move through soft rice field without sinking; the scientific name for a domestic water- buffalo is Bubalus bubalis.

The t