Does the loop keel effect the amount of leeway a yacht generates?

Leeway is often a misunderstood subject, as the ability to sail upwind is a function of the efficiency of the keel and the sails, not the direction the yacht is pointing. Because we use an asymmetric foil we can generate a force to windward when the yacht is travelling in a straight line - ie without any slippage in the water. This is obviously very different to a symmetric foil, which must slip sideways in the water to generate lift.

You can see from the diagrams of the two yachts (assuming both keels have the same lift/drag) that they will both sail in the same direction, albeit with them both pointing in slightly different directions.

It is actually easy to produce a loop keel version with negative leeway, but there is little sailing benefit. The main advantage of having no leeway is the ability to design a hull that has minimum drag along the line of the hull without the need to consider the effect of cross flows.

When accelerating the yacht it is also necessary to accelerate all of the water within the bound vortex. The result of this is that the yacht will be slowly to accelerate as if it was off higher displacement. This will also occur when the yacht is hit by a gust of wind. As the forces generated by the loop keel are reduced the bound vortex will decrease and the behaviour of the yacht will approach that of a similar vessel with a fin keel.

It is quite possible to create a rotating version of the loop keel that can be rotated to provide additional righting moment from the keel bulb as well as the dynamic righting moment generated by the keel shape.

Structurally this is far superior to a canting keel as there are two point of entry to the hull. It should also make it possible to create a watertight compartment, where the access to the keel is above the waterline. In this way any problems with the integrity of the keel will not tend to sink the yacht

A rotating loop keel will not tend to generate as much righting moment as a fin keel of the same draft, however it is quite possible to design one that can be rotated through an angle of over 100 degrees each side , when compared to a canting fin keels 50-60 degrees.