Boom (sailing)

The tree is a part of a sailboat or a sailing yacht and is used for clamping and adjusting (trimming) of the attached sail. It is named after the sail that is attached to it. So say, for example, the tree of the mainsail boom, the tree of Besansegels Besanbaum. In very rare cases, also Fockbäume find for mounting the jib, the most common headsail on yachts - The jib is usually driven without a tree. Also, the spinnaker is moved to a tree.

The (extended ) tree (1) is at its one end, generally on the gooseneck bearing (3), with the mast ( 2) and can thus both vertically and horizontally pivoted, as well as in the vertical direction to be moved out. The sail ( 4) is mounted with its bottom edge ( the leech ) on the tree. It can be done by " lined up " ( by means of thin rope that is tied in a special way ), or with sliders or the sail luff rope sewn into a groove ( the Keep) the tree top be confiscated.

For clamping and trimming the sail two tackles ( tackles ) are attached to the tree, with which the tree can be pulled down. A block and tackle (9) spanning the sail in the front region, the second tackle, the vang or holding-down device (8), the sail is stretched in the central and rear area. Is characterized by a leash attached to the rear (pictured right ), the lower sail area ( the clew ) attached ( chipped ) and a - not visible in the picture - located in the tree roller (6) is performed may also clew of the sail be tightened.

To bring this to operate the sail, so to raise the sail in the right angle to the wind, was injured the sheet ( 7) on the tree.

In traditional sailing ships, the trees were initially made ​​of solid wood, the end of the 19th and mostly made ​​in the 20th century made ​​of steel or aluminum pipe. On sailing yachts and dinghies are usually made of aluminum, to high-performance vehicles also made ​​of carbon fiber reinforced plastic.

On the tree, in addition to the above, additional linen or devices be attached: Bull Stander, Dirk ( 5), boom vang, lazy jacks and lazy bag, mainsail - recovery system with Boom cover, boom brake. In addition, in large tree - unless furler is available - usually done the reefing lines, which fix the respective clew of the sail reefed and tension the leech.

• Sailing ship