No "de-" process
Dave, the state and federal process in the US is passive; that is, you are no longer registered when you fail to return your fee and paperwork in the required time. Unlike automobiles the state does not require you to return your number plates or registration sticker (because the sticker usually expires automatically on the last day of the renewal period, so you can't go around with an invalid sticker even if you wanted to). They also don't make a fuss about removing the numbers when you aren't registered, since the sticker determines whether you are current. Likewise, the Feds don't require you to remove your old documentation number from the vessel because future owners can reactivate the number. And the Coast Guard title for a documented vessel is not normally accepted by state authorities for registration because it doesn't have complete information needed for certificate of title.So what can you do? The US Coast Guard has a web site to look up which vessels are currently still documented (see link below). I don't know how you get your vessel off the list if it is still there, but it will fall off automatically when the owner fails to pay their renewal in the course of the year.