RESISTANCE CHARACTERISTICS OF SEMI-DISPLACEMENT MEGA YACHT HULL FORMS

摘要

Mega yachts are growing in scale. The combination of cruise and maximum speeds, along with increase in hull lengthsrnresult in operational Froude numbers, F_L, between 0.3 and 1.0. The concentration of current mega yacht projects havernFL between 0.3 and 0.6 with few approaching F_L = 1.0. Hull forms with different transverse sections show a variation inrnresistance characteristics for similar slenderness ratios in this range of Froude numbers. Resistance values among otherrngeometric considerations are sensitive to slenderness ratio and longitudinal center of gravity, LCG. On occasion, LCGrnshifts, stern wedges and bulbous bows are techniques being employed to achieve minimum resistance for traditionalrndisplacement hull forms. However, these techniques need to be approached with caution as transverse instabilities canrnresult at speeds greater than 22 to 25 knots. Hull form variants incorporating flow-separating spray rails becomernsignificant at high speeds.rn500 mt was selected as being representative of a typical displacement for mega yachts. Model test data was scaled tornmake comparisons and analyses of bare hull resistance of many available experimental hull series. Thus, this paperrnaddresses resistance variations related to different hull forms, slenderness ratio and other hull characteristics along withrnsuggested design criteria for forecasting the threshold of dynamic transverse stability.