In some ports Saturdays may be days of rest and treated as holidays. They will then be excluded from "laytime". Otherwise, and unless the charterparty expressly provides (as the "Baltimore From C" charterparty does), Saturdays are like ordinary working days. If cargo work is carried out, those who are involved in these operations may have to be paid at higher rates of pay ("penalty rates) or at "overtime rates". This does not prevent Saturday from being a "working day", nor does a customary practice or not working on Saturdays.