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Ljungstrom sailboat is the name for the sailboats created by the Swedish engineer Fredrik Ljungstrom, whose interest sailing had been since childhood. The characteristics of an Lj boat are circular arc hull and the Ljungstrom rig where the mast is unsupported by rope and wire, rotatable on two ball bearings and often with double main sails but no fore sail. At their time the Lj boats were a minor revolution as they were fast, safe and easy to sail as well as relatively easy and affordable to produce. The models were named The Wing and the number (Swedish Vingen 1, Vingen 2 etc.) chronologically. A few models were built in series, such as Vingen 11A and the Twin Wing which was specifically produced or the US market. The design was not appreciated by the fairly conservative yacht clubs at the time, so the development had to be done with scarce means. A fair guess is that approximately fifty boats of different sizes have been produced. Known to still exist are about eighteen, some sailing, some undergoing renovation.〔http://sites.google.com/site/ljungstromare〕 == The Circular Arc Hull == The hull of the Ljungstrom boats are designed according to the circular arc, with a negative top line to create minimal wind turbulence around the hull, support the unstayed mast and simplify the production. To avoid wet timber ends the boards are applied from the bottom up. This way the longest board goes from stern to stern while the shortest ones are almost parallel to the railing midships. The shape gave the boats the nickname The Arch Support, but is brilliant in many ways: - When sailing it is noticed that the volume counteracting swaying is midships and that the surface exposed to the wind at the sterns is minimised which makes manoeuvring at low speed easier in narrow and windy places. - The production is simplified as the ribs are all of the same shape and that the planks are made of parallel-surfaced bars. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ljungstrom sailboat」の詳細全文を読む スポンサード リンク
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