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Hello Everyone, I need further explanation on the dimensionning of a propeller. My method is the following : Determine total resistance > assuming total resistance is equal to thrust > calculate Bu > find all coef etc ... But we always find Bp Delta diagram, but for calculating Bp we need...

thank you for your answer, I'm gonna study composite design, I found another way for a simplest evaluation, using ComposeIT. Free software by Bureau Veritas. Once laminate and pressures are defined on the soft, it compute stresses on each layer and give value for Mx, My, Nx ...

Hi, I am immersing in the BV standards (NR500 and NR546) and I am in trouble for the calculation of Nxx, Nyy, Nxy .... require to determine SigmaAd. Would anyone be able to help me on this? Thank you

Hello, I am studying resistance in order to determine power and propeller for a 9m hard chine boat, here are results given by Wolfson power prediction program using stavinsky method: Im a bit surprised at the value of thrust deduction and wake fraction, that induced odd Va and thrust...

Hi, You' re right, my reply may be confusing. There was actually 2 mistakes. The + should be a x (multiply) and the X (not E) is the distance from aft end of the boom to mainsheet attachement point. The picture of the formula explains at the best and avoids mistake. Anyway, thanks to all...

Hello, Thank you very much all, it really help me for my work. Just mind in the Stumble equation, it seems there is a mistake if I compare to the equation given on the Harken website. Mainsheet load ML=(E^2 x P^2 x .02104 x V^2) / (SqrRoot(P^2+E^2) x (E-X)) E-foot length in meters...

Hello, I would like to calculate the forces and tensions into sheets and halyards in order to dimension fittings (cleats, clutches, winches ...). Is there any formula I could use ? I only know this formula : F = pressure in sail = 1/2.ρ.S.V^2.C ρ = density of air (1.29 kg/m3) S = Sail...

Hi everyone, I still need your vote for the last rush before the end of the vote time (15th April). Please help me to participate this adventure =D Thank you very much =)

Thank you very much =) your vote is very helpful for me =)

If any other people wants to help me it would be geatful =D Thank you very much for your help =)

My main interrogation is how this coatting will resist on sea water on the long term. Secondly, Ultra Ever Dry is ultra ever expensive if you want to coat all your hull surface. And as discuss previously, it is quite non eco-friendly

Thank you very much guy, I still need vote, please take 30 sec to vote =) Don't hesitate to use all your available email (presonal, professsional/university ...) Thank you very much for your help =D

You can generaly assume for a in-line shaft a QPC of 50 - 55% Basically the QPC = hull eff. x open water eff. x rotative eff. Let's assume I have a hull given the following values at 10kts speed with a in-line shaft: hull efficiency = 0.9, Rotative efficiency = 0.95, open water efficiency =...

Hello, I would like to know what would be a typical Quasi propulsive coefficient for a Sail Drive. I know it is less than a classic shaft, but I have no idea of how much. If anyone have an idea ? I guess only the rotative efficiency is going to change. Thank you for your answers =)

Thank you soo much =)

Soooo nice guy Thank you verry much for your help =)

Hello everybody =) One of my dream would be sail on the forties. I found an opportunity to participate a leg of the Clipper Round The World Yacht race. It's an incredible chance for me to realize a dream. But I need a maximum votes to be selectable by a jury. That's the reason why I ask for...