propeller, revs. & speed

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Simple formula:  Hull Speed in kn= 2.43 3 sqrt length waterline in meter
For the 345 it is therefore: 7.5 kn. 

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Fendant Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 03 November 2012 Location: Switzerland Status: Offline Points: 1671	Post Options Post Reply Quote Fendant Report Post Thanks(0) Quote Reply Posted: 13 May 2015 at 18:17
	Simple formula: Hull Speed in kn= 2.43 3 sqrt length waterline in meter For the 345 it is therefore: 7.5 kn.
	Frank

Pepote Members Profile Send Private Message Find Members Posts Add to Buddy List Lieutenant Joined: 21 April 2015 Location: España Status: Offline Points: 37	Post Options Post Reply Quote Pepote Report Post Thanks(0) Quote Reply Posted: 13 May 2015 at 19:28
	The problem is determining the value of the constant "C" that in your calculations, you determine in 2.43. This value is not fixed as to "displacement boats" varies between 2.4 and 2.8. The hull speed limit is the speed at which the wave reaches the stern, in a short helmet with a dynamic waterline length small wave is coming soon to the stern and do not need high speed, in this case the speed limit Hull will be low, if the hull is longer with a more dynamic waterline length large fast enough to reach the stern wave is high and therefore the higher the greater length is the maximum speed limit or the hull. To calculate the speed limit that can achieve displacement ship there are several ways, all of which are empirical formulas, the most used is the following: Vm = C x √Lm In this formula (Vm) is the constant maximum speed limit or the hull (2,4≥ C ≤ 2.8), and (Lm) the waterline length, placing the vessel in meters gives the speed in knots. LWL the H345 is 9.55 meters Vm1 = C x √Lm = 2.40 x √9.55 = 7.42 kn Vm2 = C x √Lm = 2.80 x √9.55 = 8,65 kn What is the value of C? Edited by Pepote - 13 May 2015 at 19:31
	Jesús



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