"James L" wrote...

Won't the jib interfere with the main sail as it sits right in front of the
mail sail albeit of smaller size?

No. If properly set, the narrower "slot" between the main and jib actually
makes the main more effective, because the air is accelerated through the slot.
However, if the jib is trimmed too tightly, it will interfere with the main.


When running, doesn't the mail sail block the jib, almost completely?

Yes. However, see "wing and wing" in my previous message.


What is heeling?

The boat tipping to one side.


When you say "above the center of buoyancy" do you mean in front of the
center of buoyancy or are you talking height?

Height. The primary vertical forces are centered around the center of gravity
(depends on the distribution of weight in the boat -- down) and center of
buoyancy (depends mainly on hull shape -- up). The primary sideways horizontal
forces are centered around the center of effort (effective center of the sails)
and center of lateral resistance (underwater hull/centerboard/rudder profile,
looking from the side). Then there are the thrust from the sails and the drag
from air and water.