The answer to your question is proper technique.
You can paddle a canoe straight from the bow seat, a central seat, the bow seat backwards, or the stern seat. The forward stroke will require somewhat different techniques from each position.
Now think about the sitting position for all solo canoe (and kayak) experts -- marathon racers, Olympic sprint racers, outrigger ocean racers, whitewater canoe paddlers, freestyle canoe paddlers, pack canoe paddlers. They all sit in a CENTER seat, or slightly behind center.
Why? Several reasons.
First, in the center you can execute forward correction strokes at the catch (the C stroke), at the pull (the pitch stroke), at the end (the J stroke), or on an in-water return (the Canadian or palm-rolled Indian strokes). Most advanced canoeists use a combination of these corrections from a centralized seat.
Second, in the center you can reach both the on-side and off-side bow quadrants of the canoe to execute a variety of powerful turning strokes such as the bow draw, the bow pry (or jam or wedge), the cross-bow draw, and the cross-bow pry.
Third, from the center you can execute the most efficient hit & switch technique at high stroke rates with short, bent shaft paddles.
Fourth, on a center seat your center of gravity is over or close to over the canoe's pivot point (center of lateral resistance), so you can execute turns most efficiently.
Fifth, you can heel (lean) the boat most confidently for turns from the center because it's the widest point of the canoe.
Sixth, from a center seat you can pitch the bow down by moving forward on your knees to accentuate an even sharper turn.
Seventh, from a central seat you are in the best position to execute elegant drawing sideslips and prying sideslips, one of the most useful maneuvers in woody small streams and whitewater.
Eighth, in the center or slightly behind you are in the (gear-less) position that best trims the canoe onto its designed waterline and rockerline -- i.e., not having a uselessly airborne bow.
Ninth, with your centers of mass and bodily windage over the pivot point of the canoe on a centralized seat, you are best position to resist and compensate for wind-cocking and lee-cocking in strong winds.
In conclusion, your father and mine were wrong. Being in a centralized seat is optimal.
How far behind your hip you bring a propulsion stroke is a matter of technique and experience, which can be affected by the length of paddle you are using, the type of paddle (straight or bent), and your stroke rate (when racing or accelerating, you will pull out earlier; when lazily cruising, you can dangle back longer).
TECHNIQUE is everything for single blade paddling, and it can always be improved with formal instruction, long practice, and serious experimentation with different types of hulls, seating and paddles.
