There is a definitive, authoritative List of Inland Water Ships available on-line from the Veteran Benefits Administration.
Go to this site: http://www.benefits.va.gov/compensation/claims-postservice-agent_orange.asp
In the second section, titled "Eligibility - Vietnam or Korea," it says "Check the list of U.S. Navy and Coast Guard ships that operated in Vietnam to confirm whether your service aboard a ship allows VA to concede you were exposed to Agent Orange."
The link in that sentence brings you an MSWord (formatted text)Document to download. You will then have the Ships List now in use by all the Regional Offices. It is continuously being updated and, unlike the "public Website list" you have gotten used to, is not held for six months or longer for a mass update. It stays current as ship's are added.
It contains the current Rules and Background of the List and presents them by Alphabetized Hull Type, then alphabetically within each Hull Type, so you will need to know that information to proficiently use the list.