This may include customs officers, harbor masters, immigration inspectors, health and agriculture inspectors . . . Always dress cleanly and appropriately.
First impressions count.
Too many yacht captains make the mistake of showing up in bare feet and bathing suits. Dressing suitably will be greeted with respect. Keep copies of original boat documentation, state registration and other important papers when cruising abroad. DO NOT surrender original documents if possible when abroad, but rather the photocopies. Keep all papers in a dry, waterproof pouch.