setting Preparations tasks to lead Main task

[Robert H]

I have a project in the works that has a bit of a moving start date
(what project doesn’t) based on a ship’s operating schedule. So
summary project “Repair” starts shortly after the ship returns to
port. Right now it has a Must Start On constraint. I could use “Start
No Earlier Than” just as well. In either case I set the date to our
best estimate and update it as we are informed. All the tasks that
follow "Repair" are no problem but the preparations are confusing me a
little. I need to set several preparation tasks to start, or finish
in some cases, a certain period of time (days) before the Repair task
starts. I want to be able to change the Repair start date and have
all the Preparation tasks adjust accordingly.

As an experiment I set up Prep as a successor to Repair, Start to
Finish and a -4 day lag. This seems to work but it looks weird on the
Gantt. Is there another way to do this and is there any reasons not to
do it the way I have come up with?
thanks
Robert

 

[Robert H]

Yes, I am trying to schedule backwards because I dont want to have to
reschedule all the prep tasks just because the docking date shifts
seven weeks. At this point I havent started tracking the project.
Even though it is not considered "proper" does it create any risks. Is
it a no-no for a reason or is it just not "proper"

 

[Jan De Messemaeker]

Hi Robert,

Quite simple really.
Fix the ship's date with Must start on
Now set all the prep activities to an as late as possible constraint,
linking them quite normally FS to the ship's arrival.
Aven looks fine on the Gantt )

Jan De Messemaeker Project MVP
I have a project in the works that has a bit of a moving start date
(what project doesn’t) based on a ship’s operating schedule. So
summary project “Repair” starts shortly after the ship returns to
port. Right now it has a Must Start On constraint. I could use “Start
No Earlier Than” just as well. In either case I set the date to our
best estimate and update it as we are informed. All the tasks that
follow "Repair" are no problem but the preparations are confusing me a
little. I need to set several preparation tasks to start, or finish
in some cases, a certain period of time (days) before the Repair task
starts. I want to be able to change the Repair start date and have
all the Preparation tasks adjust accordingly.

As an experiment I set up Prep as a successor to Repair, Start to
Finish and a -4 day lag. This seems to work but it looks weird on the
Gantt. Is there another way to do this and is there any reasons not to
do it the way I have come up with?
thanks
Robert

 

[Jim Aksel]

I have a similar situation. It will also work fine using Jan's approach if
you set the ship docking date to "Start No Earlier Than." (SNET) or use other
schedule logic to drive teh ship docking date.

The key is the "collision" of the ASAP and ALAP tasks needs to be the
docking date.
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Jim Aksel, MVP

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