To set the time to the next 11:30 after the current time use:
skipTime ((24 + 11.5 - daytime) % 24)
More generally:
_time to SkipTo = 11.5
skipTime ((24 + _time to SkipTo - daytime) % 24)
So if it is midday this will move you to 11:30 the next day
If you don't mind the time being skipped backwards if you are already past the time you want to go to use:
skipTime (_time to SkipTo - daytime)
In this case if it is midday then you will skip back to 11:30 of the same day.