Ask HN: Project Management tool with flexible tracking time

Hi, I'm on the look out for a task tracking tool. 1. It should be able to work with just the duration of the task with the starttime and endtime of the task being optional. 2. I should be able to indicate which task depends on which. 3. After summing the expected duration of all tasks, it should give an estimate on when the tasks will be over. 4. It should have a gantt chart to show the flow of tasks. If I change the expected duration of one task, the following tasks should be changed accordingly. The problem I'm trying to solve is this. I working alone at home on a project. I have a sequence of tasks to do before the project can be launched. Some tasks take more time than I expected (the data scrubbing has been throwing up one surprise after the other :) ) and now I'm losing track of how long I have to go. It would be good to be able to track the tasks I do.