From USCG dated 6/21/2015:
"Short answer: The Towing Vessel Bridging Program (TVBP) was initiated to get the Coast Guard on every towing vessel operating in the U.S. at least once as a prelude to inspections being conducted under Sub “M”. This program had support from the industry. The decals issued are good for a period of three years.
Discussion: After the initial issuance of the decal, subsequent reissuance is done at the request of the owner/operator. It is not mandatory to participate once a decal has been issued. However, some terminals do look for a current decal before working with a vessel. There is no change is the vessel’s classification until Subchapter “M” has been promulgated and goes into effect. In some cases, the vessel will remain an uninspected towing vessel; in other cases, it will be subject to inspection for certification and must operate with a certificate of inspection. These inspections will take place over a four year period after a two-year waiting period once Sub “M” goes into effect. This waiting period will given owner/operators time to come into compliance with these new regulations."
Towing vessels that did not participate in TVBP on a voluntary basis were subsequently identified and examined at a time and place suitable to the Coast Guard. To date, over 99% of the towing vessels in the country have been examined. This is not being done with any input from any insurers or underwriters nor are they provided with specific information about vessels that have been examined, so I am not aware of how having a decal may impact a given vessel insurance costs.
Some customers, primarily the oil majors, do recognize what the decal represents and look for a current decal to be on the vessel. In some cases, it may save duplication of effort and reduce the number of examinations a given vessel will need to conduct. Our examinations are done at no cost to the owner/operator, the vessel just needs to be made available and crewed like it would be for underway operations.