Found this one when I was clearing the attic. Unfortunately it has a fold. I have no idea how it ended up in Europe/The Netherlands. I thought I would show it for those that have not seen one before or have not seen one actually used.
Required on applications for the certificate of number for motorboats of more than 10 horsepower, starting April 1, 1960. The pictorial upper part of the $3 stamp was attached to the temporary certificate and kept by the boat owner. The lower part (stub), showing number only, was affixed to the application and sent by the post office to the U.S. Coast Guard, which issued permanent certificates. The $3 fee was for three years. The $1 stamp covered charges for reissue of a lost or destroyed certificate of number. These stamps were used in the 12 states and the District of Columbia that had not passed laws in conformity with the Boating Act of 1958.
Catalogue value on license is US$55.00, however yours appears to be heavily creased.