Cat Turning Robot Boat

Cats are able to land on their feet when dropped upside down by a maneuver known as "cat-turning" which involves a turn and fold of the cat's front and back body.
Here it is simulated with two servos just to illustrate the point that angular velocity can change by an object changing its shape and no external torque applied to it.
If the maneuver were repeated over and over the boat would continue to turn.
This also can be done with a counter rotating weight but the two servos seem to drive the point home that there is motion (at least rotation) without any force (actually torque).
What if an already rotating object changed its shape? Could it change its linear velocity? It's very hard to find an authoritative discussion of the matter.

Stay tuned:)