9/19/2016 SER 101 Assignment 2 SER 101 Programming Assignment When searching for a sailboat to buy, potential buyers, use several ratios as...
9/19/2016 SER 101 Assignment 2 http://www.public.asu.edu/~atrow/ser101/assignments/16Fall/lab2.html 1/3 S E R 1 0 1 P r o g r a m m in g A s s ig n m e n t W hen searching for a sailboat to buy, potential buyers, use several ratios as "rules of thum b" to evaluate a candidate for suitability. The users get a bit tired of entering all the data and perform ing the calculations using a sim ple hand calculator. They have hired you to w rite a Python program to perform the calculations w hen they have entered the necessary data. The follow ing explainations for form ulae m ay be helpful during the evaluation of a sailboat: 1. M axim um hull speed: H ull Speed = 1.34 * LW L.5 This is the theoretical m axim um speed of a displacem ent sailboat in knots (one that does not plane a boat w hich is capable of planing m ay excape its hull speed). 2. D /L : Tons m ay be calculated by dividing displacem ent in pounds by 2,240. This ratio helps the buyer to place the boat into a light, m edium , and heavy displacem ent category. Boats less than 125 are considered ultra light displacem ent, below 200 is a very lightdisplacem ent cruiser or a lightdisplacem ent racer, below 325 is a m oderatedisplacem ent cruiser/racer and anything greater than 325 is a heavy cruiser. 3. S A /D : This ratio allow s the buyer to com pare the sail area of different boats w ith the assum ption that the only lim itation on boat speed is the displacem ent of the boat. In reality this is an oversim plification, since a poorly built light boat w ith gigantic sails m ight be m uch slow er than a m uch heavier w ell constructed boat. H ow ever, it does provide a good ballpark estim ation and is fairly w idely used to indicate boat perform ance. The next tw o ratios are pretty iffy (no one takes m uch stock in them ), but they m ight yeild a bit m ore about the boat in question's characteristics. 4. C apI: 9/19/2016 SER 101 Assignment 2 http://www.public.asu.edu/~atrow/ser101/assignments/16Fall/lab2.html 2/3 The larger the num ber, the less stable the boat, very w ide, light boats w ill score low er on this index. The m odern tendency is for boats to have a w ide beam (m ore room to spread out below ), also look at the very w ide boats sailed in the A round the W orld A lone race this past year. A gain in reality there is a lot m ore to the tendency of a boat to capsize (am ount of ballast, location of ballast, type of keal, etc). Boat stability is a very com plex m atter (stability curves are published by U S Sailing on m ost boats afloat in U S w aters today). 5. C om fI: O f the various ratios this one is the m ost tenuous.. In m any respects it seem s to be the opposite of the C apI w ith the w ider beam increasing the com fort. O h w ell, it is just an excersize. The program you are to w rite is to provide the input fields for the follow ing input item s: LO A (total length for the vessel) LW L (w ater line length for the vessel) Beam (w idth for the vessel) D isplacem ent Sail area If the input to your program is: 34.5 24.0 10.2 11200 483 Your program w ill be expected to output the follow ing inform ation: LO A : 34.50 LW L: 24.00 Beam : 10.20 D isplacem ent: 11200.00 Sail area: 483.00 H ull speed: 6.56 D /L: 361.69 SA /D : 15.17 C apsize index: 1.86 C om fort index: 28.91 You m ight also look at w w w.im ageination.com /sailcalc.htm l for an exam ple. 9/19/2016 SER 101 Assignment 2 http://www.public.asu.edu/~atrow/ser101/assignments/16Fall/lab2.html 3/3 S om e specifications for you to w ork w ith: Sailboat LO A LW L B eam Sail A rea D isplacem ent Tartan 34C 34.5 25.0 10.2 483 11,200 Tartan 37C 37.3 28.5 11.75 625 15,500 C ontessa 32 32 24 9.5 562 9500 Swan 38 38.25 28.7 11.6 826 18,300 Int 505 16.5 16 6.1 175 290 (em pty) 600 (w ith crew ) W ayfarer 15.8 14.8 6.1 141 365 (em pty) 676 (w ith crew ) H erreshoff H 12 1/2 15.6 12.5 6 133 1350