b"Loading FormulasBlock Loading vs Angle of DeflectionLoad on a block is a combination of the load on the line passing through the block, plus a block-loading factor, which is determined by the angle by which the block turns the sheet. For example, a foot-block that turns a sheet 180 degrees will see a load equal to twice the load on the sheet. A deck organizer, which turns a halyard only 30 degrees, will see just 52 percent of the load on the halyard. Boat TypeMost load formulas assume a medium displacement monohull, but you can easily correct for other boat types. Multihulls and boats with canting keels or water ballast have great form stability and speed and will often carry sails very high in the apparent wind speed, so calculations must be done with this wind speed in mind. ULDBs areAngle of Load Angle of Load Angle of Loadtypically tender and often change sails or reef quite early, so loadingde ection factor de ection factor de ection factormay be done at relatively low wind speeds. For example, a modern30 52% 90 141% 150 193%trimaran may carry its blade jib in 25 knots of wind at speeds over45 76% 105 159% 160 197%15 knots for an apparent wind of nearly 40 knots, whereas a ULDB60 100% 120 173% 180 200%will probably remove its #1 genoa at about 15 knots of apparent wind. 75 122% 135 185%Genoa System LoadingBecause wind speed is squared, it is the most important variable and can greatly influence loading. Wind speed (the apparent wind) should be calculated for the specific sail being analyzed. For example, the #1.3 x Car Load .5 x Car Loadgenoa on a 7 m (25') boat might only be carried in 15 knots of wind, while the #3 blade on a Maxi-boat could well be carried in 40 knots. GENOA SHEET LOADEnglish MetricTo calculate loading on a genoa lead car, multiply sheet load by theSL = SA x V 2x 0.00431 SL = SA x V 2x 0.02104load factor of the sheet. Most #1 genoas will deflect about 45 degrees,SL Sheet load in pounds SL Sheet load in kilogramswhile a #3 genoa may deflect 75 degrees or more. SA Sail area in square feet SA Sail area in square metersLead car adjuster tackle load is dependent on the angle of deflectionV Wind speed in knots V Wind speed in knotsof the sheet in the lead car, but is generally assumed to be 0.3 of leadFormulas are for typical cruising monohulls with fixed keel and Dacron sails, car load when deflection is 45 degrees and .05 of lead car load whensheets, and halyards. For all other types, please contact Harken for technical deflection is 60 degrees. assistance in calculating loads.Mainsheet System Loading MAINSHEET LOADEnglish MetricThe formula for mainsheet loading is not as widely acceptedML = E 2x P 2x 0.00431 x V 2 ML = E 2x P 2x 0.02104 x V 2as that for genoa sheet loads and should only be used as a rough( P 2+ E 2 ) x (E - X) ( P 2+ E 2 ) x (E - X)guide for offshore boats from 9 - 18 m (30 - 60'). ML Mainsheet load in pounds ML Mainsheet load in kilogramsTraveler car adjuster load is generally considered to be 0.2 timesE Foot length of main in feet E Foot length of main in meterscar load. P Luff length of main in feet P Luff length of main in metersV Wind speed in knots V Wind speed in knotsX Distance from aft end of boom to X Distance from aft end of boom tomainsheet attachment point in feet mainsheet attachment point in meters.2 x Car Load Formulas are for typical cruising monohulls with fixed keel and Dacron sails, sheets, and halyards. Assumes standard roach of 7.5%. For large roach sails such as flattops multiply calculated load by the percentage of the mainsail roach. If a sail has 25% roach, multiply the calculated load by 1.25. For all other types, please contact Harken for technical assistance in calculating loads. Rig DimensionsThe following abbreviations are often used to describe various measurements on a sailboat. Precisetechnical definitions exist for each abbreviation, but the following is a list of simple descriptions:LOA Length overall - overall tip-to-tip length of the boat I 2 Height of staysail halyard above deck PLWL Length waterline - length of waterline of the boat J Base of the foretriangle measured from the front of the I 2 Imast to the intersection of the forestay and deck EDWL Design waterline - theoretical waterline length of boatJ 2 Base of staysail triangleas opposed to LWL, which is actual waterline lengthBMX Beam maximum - width of the boat at the widest point P Luff length of the mainsailBWL Beam waterline - widest beam of boat at the waterline E Foot length of the mainsail J 2I Height of the foretriangle measured from the top of theLP Shortest distance from headstay to the clew of the jib Jhighest sheave to the sheerlineDacron is a registered trademark of E. I. du Pont de Nemours and Company or its af liates.275"