A box shaped pontoon of length 100 m, breadth 12 m and draft 10 m is floating in water of density 1 tonne/m\(^3\). The roll radius of gyration is 1% of the ship's length and the roll added mass moment of inertia is 20% of the roll mass moment of inertia. The vertical centre of buoyancy is located at half of the draft, and the vertical centre of gravity is at 6 m from the keel.
The roll natural frequency of the pontoon is ______ rad/s (rounded off to two decimal places).
Assume g = 10 m/s\(^2\).
