Adding up overtime

[Marc]

I'm trying to add up overtime over one row. (See below) Assuming 16:30 is
normal quitting time how would I set up a formula to add up the total time
worked passed 16:30?

Total OT M T u W Th
Fr
Smith xx hours 16:00 16:30 16:30 17:15 16:45

Any ideas? Thanks!