Spoiler for smart maiden outwits ogre!Assuming that the maiden's goal is merely to get out of the lake without encountering the ogre, that she has no particular direction she is obliged to go.
Wouldn't it behoove the maiden to perform continuous reevaluations of her course and steer to the spot currently opposite the ogre at every moment? I'll bet she'd have to be terribly slow oarswoman to lose this race. (However, I don't have the numbers...
The reason I ask is that this could be translated in this manner
a maiden that is on the brink of winning the contest sees the ogre is 2 or 3 meters away choose instead of grasping victory cross almost the entire length of the lake once more to get the opposite side of the lake from the ogre
At a guess maiden needs to be able to go over 1 1/3 miles per hour travels pi * lake radius/2 while the ogre runs 3/4 of the way around the lake