It depends on a variety of factors:
1. other boat traffic, commercial tows have priority over pleasure craft
2. the size of the drop, some are 15 feet, others are over 50 feet
3. the posibility of repair work being done on a lock chamber, creating delays
If you're lucky and hit them just right, on average, 45 minutes, but you may be delayed one, two hours, perhaps overnight if there is an emergency chamber closure.
Where are you headed?
M/V The 69 Queen
1969 River Queen 40'
and a 24' Pontoon "Red Solo Cup"
Port of Fulton, MS