The velocity of the boat relative to the water is 6.0 m/s, and the velocity of the water is 2.5 m/s. To find the compass direction of the boat, we need to subtract the velocity of the water from the velocity of the boat.
6.0 m/s - 2.5 m/s = 3.5 m/s
Since the boat is oriented due East, and the velocity is 3.5 m/s, the compass direction of the boat is 35° East of South.
Therefore, the answer is 35.