: Does it increase drag vs. a centered skeg or affect turning? I'm trying to
: understand why it works right, but am having a hard to understanding. How
: offset should one go?

Hi Bryan,
From dinghy's, there's no real diference between an offset and a centerline centerboard in drag, assuming they're the same shape and size. The same would apply to skegs.
If the skeg is close to the keel, there would be no turning force from the skeg drag.
Even if it was gunwale mounted, the turning force from offset drag wouldn't be noticable in a kayak.
If the slot is offset enough to clear the ground if beached, maybe an inch depending on deadrise, it would feel just like a centerline skeg.

The reason why it works is to do with the ratio of waterline length and amount of offset. A greenland kayak would have a overall ratio of about 165 to 1, a very poor leverage for the skeg. Plus it's at the back-end. The dinghy's I saw where about 12' on the waterline with a 2-3 inch offset, at best a ratio of 72 to 1. Better leverage but it didn't effect directional stability.

Hope this helps,
Mike Savage
South West Cork