You should not need to force bask. Just because you do not see your turtles basking does not mean they do not bask.

What do you do if your turtle won't bask?

If the temperatures (water or basking) are too low, turtles will be sluggish and may not bask. ... If the water is much warmer than recommended or the ambient air temperature is too cool, the turtles will be unlikely to get out of the water to bask. Basking is essential for the turtle's health.

How many hours a day do turtles need to bask?

Turtles generally bask between 2 to 8 hours each day. Most turtles such as map turtles and sliders follow this basking routine, and isn't an issue as far as the turtle returns to the water each day and stays there for significant amounts of time.