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/docs/shiplist.docx
This should immediately download an MS Word (formatted text) Document. 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. The best way to find a ship is to use the "search" function in MSWord.
This is the only "Inland Waters Ship List" that is currently recognized by the VA as providing proof for the five Inland Water Service categories. The Alphabetized Ships List originally on the Internet is no longer maintained by the VA, and all the updating is made on the list that is linked above.
The VA will only recognize ships that can provide actual documentation of having performed the duty you specify rather than making "comparisons" to other ships that may have done the same duty. In the VA regulations, they state that each claim is decided on its own merits. This includes the doctrine that any claim awarded, unless purposefully intended through the involvement of a 3-member panel of Judges at the Board of Appeals or the Court of Appeals for Veteran Claims, is awarded on its own merits and does not set a precedent for any claims to follow.
Additional facts to note are:
Any status afforded to a veteran by the VA Health Administration has no bearing on the determining factors specified by the Compensation Division for award of presumption of exposure or direct exposure. The VA Health Administration may make statements about herbicide-related exposures, diseases, etc., but until the Compensation Division awards disability for exposure to herbicide, those statements only refer to treatment within the hospital system for purposes of medication discounts and priority of treatment. This may seem counter-intuitive, but the Health Care System and the Compensation Division do not always share data, and the Compensation Division rulings trump any Health Care status every time, including enrollment letters.
Only evidence that follows the guidelines given above will be taken into consideration when determining a claim for disability based on herbicide exposure. Any other information provided must tie back to those guidelines.