You can view or enter ports serviced by the contact. On the Address Book entry, click 
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For Bunker Vendors, the Remarks field can be used to record information like past issues, bunkering limitations, and performance ratings. After configuring the vendors that service a port, the Vendor selection list in a Bunker Requirement for that port has two sections. The top shows the vendors recorded as serving that port; the bottom lists all bunker vendors in the Address Book.