Somewhere else I found similar formulas to calculate the horsepower of sail area at different wind strengths, and the expected sheet loads, but this is more for a winter discussion. Typically a displacement hull needs X horsepower (your engine size is a good starting point.) to reach hullspeed and the amount of sail area needed to produce that power decreases as the wind speed increases.
----- Original Message ----- From: "PME via CnC-List" <[email protected]> To: [email protected] Cc: "PME" <[email protected]> Sent: Tuesday, July 14, 2015 12:39:46 PM Subject: Re: Stus-List Best Engine? -> hull speed and power required Hi, There is a nice web calculator for calculating hull speed, a displacement corrected hull speed (Gerr), and horsepower dependence on speed. It shows for the LF38, a Gerr hull speed of 7.22 Knots and required 35.5 HP to reach 100% of max hull speed. It is interesting to note that 90% of hull speed is expected to be achieved with under 24 HP. http://www.psychosnail.com/boatspeedcalculator.aspx - Paul E. 1981 C&C Landfall 38 S/V Johanna Rose Carrabelle, FL On Jul 14, 2015, at 12:00 PM, [email protected] wrote: HI Brian Our 34 has the Yanmar 3GM with Martec folding prop. Clean bottom cruising is 5.5, max is about 6. As I recall, your max speed is supposed to be about 80% of theoretical hull speed with throttle wide open?? Another variable is the calibration of the knotometer and if using the GPS the impact of current John and Maryann Legacy III 1982 C&C 34 Noank, CT _______________________________________________ Email address: [email protected] To change your list preferences, including unsubscribing -- go to the bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
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