Regarding Websters Ship Maneuvering Fix.
The Displacements: may be the same between the Fix and FOTRS, but the Mass: is quite larger than FOTRS. Also changed is the GravityCenter: position. Both will change how the ship sits in the water and what it will do in wind.
I'm just not convinced that having a ship increased in weight, with the possibility of it sitting lower in the water (I'm not sure if this is what it will do or not....been too long ago to remember whether it's Displacement, Mass, or both, that makes the ship heavier) to the point the center of gravity needs to be re adjusted, is the right way to go about slowing down the performance. It's a tricky business making a ship heavier for cutting down performance, and needing to move the center of gravity so it stays afloat in all conditions.
Did Webster do it right....maybe he did. I don't know. I just know what I ran across years ago with his mod.