2020 12 23 Examples with « Gene-Hull Sailboat_Stab1.0 » Jean-François Masset – December 2020 [email protected] « Gene-Hull Sailboat_Stab 1.0 » spreadsheet application is here illustrated through 4 examples : – V1 classic modern sailboat (the reference boat in « Gene-Hull Sailboat 3.1 ») – S30, inspired by S30 / Knud Reimers – Blue Water 39, inspired by Corbin 39 / Robert Dufour - Marius Corbin – F3, inspired by Beneteau Figaro III / VPLP Boat V1 modern classic daysailer Hull and appendages Loa 10,30 m ; Lwl 8,00 m ; B 2,60 m ; Draft 1,75 m ; Light weight : 2652 kg ; Keel-bulb 1092 kg 200 100 0 -200 -100 0 100 200 300 400 500 600 700 800 900 1000 -100 -200 200 100 0 -200 -100 0 100 200 300 400 500 600 700 800 900 1000 -100 -200 150 150 100 100 50 50 0 0 -150 -100 -50 0 50 100 150 -150 -100 -50 0 50 100 150 -50 -50 -100 -100 -150 -150 -200 -200 Sailplan SA (m2) ZCE (m) Zdeck (m) Zmast (m) Main (m2) Spi (m2) ZCE spi (m) 43,61 5,37 0,85 13,23 24,09 68,34 6,35 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 -200 -100 0 100 200 300 400 500 600 700 800 900 1000 -100 -200 -300 Boat V1 / Introduction of a load and its position Xg, Zg, Yg : – for the computation of the GZ curve up to 180°, it is recommended to put Yg = 0 (Crew at center), as done here below. – at contrary, for the knowledge of the righting moment RM in sailing conditions (usually up to heel 30°), it is recommended to put an Yg representative of the crew sit windward Mass spreadsheet with input of a load Mass Xg Zg Yg (kg) (m) (m) (m) Boat light weight (kg) 2652,06 3,711 0,020 0 Data to enter Load (kg) 300,00 2,40 0,85 0,00 Crew at center yellow cells 0,85 0,00 Crew sit windward Total >>> Mass (kg) 2952,06 3,578 0,104 0,000 Crew at center Disp. (m3) 2,88005 0,104 0,000 Crew sit windward Computation of the GZ with a flush deck : for a first approach of the GZ curve, one can assume that the volume of the cabin roof and the recess of the cockpit roughly compensate, and that the computation with a flush deck is significant enough for an early stage project. >>> To input Kroof (%B) = 0 (Cell B53) That said, the influence of a cabin roof volume can be showed by doing also the computation with the Kroof of the project , here with Kroof = 29 Typical process : to build the GZ curve up to 180° with a step of 5° Input an heel angle (here 20) : Data to enter : yellow cell Results (with Yg for crew sit windward) Heel (°) 20 Disp. (m3) 2,88005 / Disp. (m3) 2,88005 > Height (cm) 3,7 Xc heel (m) 3,578 / Xg (m) 3,578 > Trim (°) 0,02 Yc heel (m) -0,343 Yg heel (m) -0,036 Zc heel (m) -0,192 > GZ (m) 0,307 Sw heel (m2) 17,79 RM (kN.m) 8,897 Bwl heel (m) 2,01 FB mini (cm) 26,9 Xf (Heel) – Xf (0°) (%Lwl) -0,69 Obliquity (°) 2,97 Check % convergence 0,00 : Disp 0,00 : X Kvol. : 1,000 The computation of the equilibrium is quasi real time (about 0,5 seconde on my PC) : The convergence accuracy is given, here 0,00 % of the deviations for both the Displacements and the Xs. Kvol. is the volume ratio of the keel in the water, here Kvol 1 = fully immerged. The computation of the equilibrium is quasi real time (about 0,5 seconde on my PC). On the right side, the values of heel , trim and GZ is recopied : Data to copy/special paste (number, format) in the table here below Heel (°) Trim (°) GZ (m) 20,00 0,02 0,307 >>> to copy/special paste (number, format) these 3 values in the table here under : GZ data storage (by copy/special paste) Heel (°) Trim (°) GZ (m) 0,00 0,45 -0,001 5,00 0,42 0,088 10,00 0,34 0,171 15,00 0,20 0,245 20,00 0,02 0,307 Once the complete process is done, that leads to this table here below, that you can complement by the input of another Zg if you have an uncertainty on this value at early stage : GZ data storage (by copy/special paste) Input new Zg 0,150 Heel (°) Trim (°) GZ (m) GZ (m) 0,00 0,446 -0,001 -0,001 5,00 0,418 0,088 0,084 10,00 0,336 0,171 0,163 15,00 0,202 0,245 0,233 20,00 0,023 0,307 0,292 25,00 -0,192 0,359 0,340 30,00 -0,437 0,403 0,380 35,00 -0,702 0,439 0,413 40,00 -0,970 0,465 0,436 45,00 -1,235 0,480 0,447 50,00 -1,481 0,483 0,448 55,00 -1,689 0,475 0,438 60,00 -1,857 0,460 0,421 65,00 -1,987 0,444 0,402 70,00 -2,087 0,439 0,396 75,00 -2,169 0,429 0,384 80,00 -2,235 0,387 0,341 85,00 -2,259 0,336 0,291 90,00 -2,260 0,283 0,237 95,00 -2,241 0,226 0,180 100,00 -2,196 0,167 0,122 105,00 -2,122 0,107 0,063 110,00 -2,025 0,047 0,004 115,00 -1,905 -0,013 -0,055 120,00 -1,760 -0,072 -0,112 125,00 -1,601 -0,130 -0,167 130,00 -1,416 -0,184 -0,219 135,00 -1,224 -0,234 -0,267 140,00 -1,017 -0,279 -0,309 145,00 -0,804 -0,317 -0,344 150,00 -0,589 -0,347 -0,370 155,00 -0,378 -0,365 -0,384 160,00 -0,182 -0,367 -0,382 165,00 -0,008 -0,347 -0,358 170,00 0,121 -0,290 -0,298 175,00 0,182 -0,174 -0,178 180,00 0,182 0,000 0,000 AVS (°) AVS (°) 113,88 110,32 Areas ratio Areas ratio 2,33 1,89 The angle of vanishing stability (AVS) is output : here respectively 113,88° and 110,32° The Areas ratio (positive area / negative area under the Gz curve) are also given, representative of the stability (to avoid) in upside down configuration : the higher the ratio, the better the unstability in upside down configuration. It is a criteria relevant when sailing in open ocean conditions far from a shelter, e.g. mentioned in the Imoca class rules (Areas ratio > 5). The corresponding GZ curves and the Trim curve are also output : GZ curve Blue : with initial Zg ; Red : with new input Zg 0,6 0,5 0,4 0,3 0,2 ) m 0,1 ( Z 0,0 G -0,1 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 -0,2 -0,3 -0,4 -0,5 Heel (°) Trim (computed in the fixed vertical plan) 1,0 0,5 0,0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 ) ° -0,5 ( m i r T -1,0 -1,5 -2,0 -2,5 Heel (°) Boat V1 / Some typical heeling configurations : At heel 15° >>> GZ = 0,245 m 150 150 100 100 50 50 0 0 -200 -150 -100 -50 0 50 100 150-200 -150 -100 -50 0 50 100 150 -50 -50 -100 -100 -150 -150 -200 -200 At heel 30° >>> GZ = 0,403 m 200 200 150 150 100 100 50 50 0 0 -200 -150 -100 -50 0 50 100 150-200 -150 -100 -50 0 50 100 150 -50 -50 -100 -100 -150 -150 -200 -200 At heel 45° >>> GZ = 0,480 m 200 200 150 150 100 100 50 50 0 0 -200 -150 -100 -50 0 50 100 150-200 -150 -100 -50 0 50 100 150 -50 -50 -100 -100 -150 -150 At heel 60° >>> GZ = 0,460 m 250 250 200 200 150 150 100 100 50 50 0 0 -150 -100 -50 0 50 100 150 200-150 -100 -50 0 50 100 150 200 -50 -50 -100 -100 At heel 75° >>> GZ = 0,429 m 250 250 200 200 150 150 100 100 50 50 0 0 -150 -100 -50 0 50 100 150 200-150 -100 -50 0 50 100 150 200 -50 -50 -100 -100 At heel 90° >>> GZ = 0,283 m 250 250 200 200 150 150 100 100 50 50 0 0 -150 -100 -50 0 50 100 150 200-150 -100 -50 0 50 100 150 200 -50 -50 -100 -100 At heel = 105° >>> GZ = 0,107 m 250 250 200 200 150 150 100 100 50 50 0 0 -150 -100 -50 0 50 100 150 200-150 -100 -50 0 50 100 150 200 -50 -50 -100 -100 At heel 113,88° >>> GZ = 0,000 m Angle of Vanishing Stability 250 250 200 200 150 150 100 100 50 50 0 0 -150 -100 -50 0 50 100 150 200-150 -100 -50 0 50 100 150 200 -50 -50 -100 -100 At heel 135° >>> GZ = - 0,234 m 250 250 200 200 150 150 100 100 50 50 0 0 -200 -150 -100 -50 0 50 100 150-200 -150 -100 -50 0 50 100 150 -50 -50 -100 -100 At heel 150° >>> GZ = - 0,347 m 250 250 200 200 150 150 100 100 50 50 0 0 -200 -150 -100 -50 0 50 100 150-200 -150 -100 -50 0 50 100 150 -50 -50 -100 -100 At heel = 165° >>> GZ = - 0,347 m 250 250 200 200 150 150 100 100 50 50 0 0 -200 -150 -100 -50 0 50 100 150-200 -150 -100 -50 0 50 100 150 -50 -50 -100 -100 At heel 180° >>> GZ = 0,000 m 250 250 200 200 150 150 100 100 50 50 0 0 -150 -100 -50 0 50 100 150-150 -100 -50 0 50 100 150 -50 -50 Boat V1 / STIX The sheet « STIX » proposes the computation of the Stability Index STIX according to ISO 12217-2 2013.