|
The Thames A Class Rater is both a historic and modern specialist sailing craft designed for the particular conditions at Thames Sailing Club, on the River Thames at Surbiton in England. The rules〔(Rules of The Thames "A" Rater Association )〕 refer to the craft as a yacht. The rig is lofty, supported by standing rigging and usually by runners,〔A runner is one of a pair of running backstays. It is rigged between a point towards the boat's quarter and one usually fairly high on the mast. That on the windward side is tensioned to support the mast against the drive of the wind on the sail, while the leeward one is slackened to permit the mainsail to take an efficient shape. So that the tensioning and relaxation can be done rapidly as the boat goes about, a highfield lever is normally used.〕 and the hull is a scow with metal centreplate. All boats built before 1922 are made from wood whilst those built since are of a different construction. The rater is extremely fast, planes easily, and is a technically highly challenging boat to sail in anything above moderate wind conditions. It is usually sailed with a crew of three. Raters have traditionally commuted by river under tow between Thames Sailing Club at Surbiton and Upper Thames Sailing Club at Bourne End, Buckinghamshire. ==Rater Development== Over the years raters have developed extraordinarily tall masts and high aspect mainsails to meet the local conditions, and catch the wind above the trees and other obstructions along the banks. Their sails were always large, but originally they had long booms and shorter masts, but over time the booms got shorter and the masts taller. At first they used the so-called balance lug rig, then the Gunter rig, before moving on to the current Bermuda rig. Over the years bamboo spars were replaced first by wood, then aluminium, and now mostly carbon fibre. 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「Thames A-class rater」の詳細全文を読む スポンサード リンク
|