SA, since this is not available in biased web pages that discuss politics from one point of view only, I will try to make it as simple as possible, and have, in the mean time produced 2 drawings that will help you uinderstand what I mean, since words is not my forte. So to be concise and explicit, something you know not how to do, here I go:
Basically after the 80's and with the abandoning of the IOR design tendencies, the trend in the design of modern boats, called for keels that became more and more thiner, and and also narrower in their aspect ratios but also further forward than they used to be.
Add to that the fact that boats designed now are normlly faster that what they used to be (when the books you read were written), due to larger sailplans and more efficient
rigging, the design of the keels had to change to a point where they are now also deeper than they were before. By doing all this, the general trend in modern boats is to have the keel further away from the rudder.
Therefore, the turbulence caused by the trailing edge disrupted flow vortexes, became less effective in causing flow disruptances on the rudder. A fact I tried to joke with you by mentioning 1800's designs.
These vortex induced turbulences and disrutions do cause vibration and can cause flutter at or above ceratin speeds, but does not reduce the effectivness of the rudder by values that cause concern. Not in modern design.
Linear Mode
