Ceremonial ship launching

Ceremonial ship launching involves the performance of ceremonies associated with the process of transferring a vessel to the water. It is a nautical tradition in many cultures, dating back thousands of years, to accompany the physical process with ceremonies which have been observed as public celebration and a solemn blessing, usually but not always, in association with the launch itself. Ship launching imposes stresses on the ship not met during normal operation and in addition to the size and weight of the vessel represents a considerable engineering challenge as well as a public spectacle. The process also involves many traditions intended to invite good luck, such as christening by breaking a sacrificial bottle of champagne over the bow as the ship is named aloud and launched. There are three principal methods of conveying a new ship from building site to water, only two of which are called "launching". The oldest, most familiar, and most widely used is the end-on launch, in which the vessel slides down an inclined slipway, usually stern first. With the side launch, the ship enters the water broadside. This method came into use in the 19th century on inland waters, rivers, and lakes, and was more widely adopted during World War II. The third method is float-out, used for ships that are built in basins or dry docks and then floated by admitting water into the dock. If launched in a restrictive waterway, drag chains are used to slow the ship speed to prevent it striking the opposite bank. Normally, ways are arranged perpendicular to the shore line (or as nearly so as the water and maximum length of vessel allows) and the ship is built with its stern facing the water. Where the launch takes place into a narrow river, the building slips may be at a shallow angle rather than perpendicular, even though this requires a longer slipway when launching. Modern slipways take the form of a reinforced concrete mat of sufficient strength to support the vessel, with two "barricades" that extend well below the water level taking into account tidal variations.