If you have set up shared mailbox folders to match then
Set ContactFolder = ObjMAPI.Folders("Public Folders").Folders("All Public Folders").Folders("Vessel COM").Folders("Vessel COM Contacts")
might be changed to
Set rootFolder = ObjMAPI.Folders("Public Folders").Folders("All Public Folders")
Set ContactFolder = rootFolder.Folders("Vessel COM").Folders("Vessel COM Contacts")
Once you change all the places with a public folder reference and this looks like it is working then
Set rootFolder = ObjMAPI.Folders("Name of Shared Mailbox").Folders("Inbox")