Mast & Keel Positioning / Brasil student

[Windvang]

I wonder how it works with canting keel boats, they usually have CLR ahead CE, certainly in CTBF configuration, any way you calculate them.

[frosh]

Hi Cliff, you have commenced your argument like a few others on a false premise; that the boat will sailed heeled. The originator has stated clearly that the boat he has in mind is a centreboarder capable of planing. In a previous post I have already stated that the correct way to sail this type of boat when powered up is flat!

Windvang, that's not correct about CBTF. The same method is used as on a normal boat with the CLR calculated as half way between the quarter chord points of the vertical foils."Lead" is based on a similar method to that mentioned in Larsson and Eliassons book-CE leads CLR by a certain percentage of the waterline length.The important thing, in my opinion, about both the "present method" of Larsson and Eliasson and Skenes older method is that they don't claim a scientific explanation of balance(there's just too much going on): they simply provide a METHOD(Rule of Thumb) that has been proven, throughout many years, to work.
One important factor is that the bulb and keel fin(strut) are NOT included in the determination of balance on a CBTF boat because when sailed upwind "collective" is used which means, for all pratical purposes, that the fin(strut) and bulb develop NO lateral
resistance.