Re: sailing documents
The US does not have a clearance out requirement at least not for US boats. If you want to leave then just leave. However, in the Caribbean every single island I went to (a dozen or so) wanted to see documentation, not state registration. I watched a guy get refused entry to Martinique for not having ORIGINAL documentation. A copy is no good. No customs official ever wanted proof of insurance but marinas almost always do.
And in Antigua they are VERY serious about the captain ONLY getting off the boat to clear in. I heard of massive fines if they catch you breaking this rule. Other islands were more laid back about it.