Rob
Ansys Employee
You have a solution so have flow data to plot and report on. You should only have one volume in Fluent and the wetted surface (boat hull) is the one to report on. I was querying the solver as sometimes CFD Post (Results box in Workbench workflow) and Fluent multiphase don't play well together. Force reporting in Fluent should work.
Can you post a screen shot of the error & panels you're using? may need to step in if it's CFD Post as I very rarely use it.