We constructed a 6-degrees of freedom rotational model of Titan as a 3-layer body consisting of a rigid core , a fluid global ocean , and a floating ice shell .
The ice shell exhibits partially-compensated lateral thickness variations in order to simultaneously match the observed degree-two gravity and shape coefficients .
The rotational dynamics are affected by the gravitational torque of Saturn , the gravitational coupling between the inner core and the shell , and the pressure coupling at the fluid-solid boundaries .
Between 10 and 13 \% of our model Titans have an obliquity ( due to a resonance with the 29.5 -year periodic annual forcing ) that is consistent with the observed value .

The shells of the successful models have a mean thickness of 130 to 140 km , and an ocean of \approx 250 km thickness .
Our simulations of the obliquity evolution show that the Cassini obliquity measurement is an instantaneous one , and does not represent a mean value .
Future measurements of the time derivative of the obliquity would help to refine the interior models .
We expect in particular a variation of roughly 7 arcmin over the duration of the Cassini mission .