[whpalmer4]

For most people, start date is the date/time at which you can start working on something, not necessarily the time you do start working on it. If I have a project to write a report involving three tasks, all of which I can't start until Monday, and the whole thing is due Friday at 5pm, how can you possibly draw a useful Gantt chart without more information, except one that just shows the week blocked out because I might be working on the report?

It sounds like you might want something like Skoach.