In Local Booking manager system you can setup a discount for specific sailing period, order period and choose the charter duration.
2. Add new discount
Add a discount and choose Trigger type - Service duration. By entering duration of days, discount can be valid for specific sailing period, order period and charter duration. After you have set conditions, click Apply.
3. Go to main screen.
Choose a sailing period and choose duration of charter to check if the discount is valid.