Dictionary Search Results
For a selection of basic naval terms, see the log and report glossary.
- cradle, launching
- nautical: The structure of wood, or wood and steel, which is built up from the sliding ways, closely fitting the shell plating, which supports the weight of the ship and distributes it to the sliding ways when a ship is being launched. The extent of the cradle and the number of sections into which it may be divided depends on the weight and length of the ship.
- nautical: A term applied to the operation of transferring a vessel from the building ways into the water. End launching and side launching methods are employed; the former method is used when the vessel is built at an angle, usually at right angles, to the waterfront and the vessel is launched stern first, while in side launching the vessel is built parallel to the waterfront and launched sidewise. In preparing for an end launching, usually groundways, made of heavy timbers are laid with an inclination of about ½" and 5/8" to the foot parallel to the center line of the ship one on either side of the keel, and spaced about one-third of the beam of the vessel apart. These groundways run the length of the vessel and for some distance out under the water. On top of the groundways are placed the sliding ways, also heavy timbers, and between these two ways is placed a coating of launching grease. The sliding ways are prevented from sliding on the greased groundways by a trigger or similar device and dog or dagger shores. Cradles are built up to fit the form of the vessel, and between the sliding ways and the cradle, wedges are driven and the weight of the ship thus transferred from the building blocks to the sliding ways. After the building blocks and shores are removed, the trigger is released and gravity causes the vessel to slide down the inclined ways. In some cases hydraulic jacks are set at the upper end of the groundways to exert pressure on the sliding ways to assist in overcoming initial friction along the ways. A similar procedure is followed in the case of side launchings, except that more than two groundways are usually used, depending on the length of the ship, and the inclination of the ways is steeper.