In lower gravity, you could expect to swim faster
I am not answering the other questions as I do not have much more to
say which is not already said in other answers. But I do disagree with their conclusion that swimming would be
Regarding swimming, one would need a better understanding of swimming
motion to decide how much effect can be expected from low gravity. But
there is a point at which faster swimming should be possible. Here is
It is quite clear that static buoyancy does not change since it is
dependent on density ratio, not on the intensity of gravitational
Drag, resistance of water to motion is also the same, so that it does not
change when buoyancy is unchanged, and the body is immerged to the same
level. Drag is the major factor that slows the swimmer, and it depends
heavily on how immerged he is.
This is so true that, for a while, swimming champions used the more
buoyant polyurethane swimsuits until they were banned in 2009.
However, there is more to immersion than static application of the
Archimedes' principle to control buoyancy. There are also dynamic
forces due to the motion of the body in the fluid that can induce
vertical forces in addition to drag, in the same way that an airplane
is submitted to a vertical uplift that maintains it in the air.
By controling the position of his body of of his hands, the swimmer can
create a vertical lift that can push her above water, as is done by
hydrofoils. This additional lift can be seen as extra buoyancy,
lifting a bit the swimmer outside the water, thus reducing the drag
of the liquid allowing for greater speed and/or less energy
This possibility is apparently not analyzed in physical studies of
swimming efficiency, but probably because lifting the weight of the
swimmer in Earth gravity is too demanding to be effective.
However, this need not be so in a reduced gravity. If we go to the
extreme, lifting the body is very easy in near zero gravity
(though you do want some gravity to keep air and water separate).
Without going to that extreme, there must be a gravity level at which
body and hand attitude can create some lift pushing the body outside
the water to reduce the drag of swimming in the water. But it is
difficult to be more precise before we have an olympic swimming pool
on the moon to mesure the possibilities in field experiments.