I have hired a few boats in the Florida Keys, only sportboats not cruisers or yachts, they asked for nothing except your word that you were experienced, this was for 40+ knots power craft. They seem to treat them like hiring a car out there, so if you have a ICC you should have no problem.
There is no formal qualification required but you will probably need to do a "charter check-out" before they let you sail off - muster crew, leave and return to dock, anchor etc. One interesting point - it is theoretically against the law for a non-US citizen to skipper a US-flagged vessel. I've never discovered how the charter firms get over that - the ones I used to work for just ignored it but I noticed recently that a Brit was prosecuted for this offence.
A little clarification is need here: a non-US citizen cannot be in command of a Coast Guard documented vessel (federal documentation) but can perfectly well be in command or evn own a state registered vessel (for instance, regist3ereed in New York or in Florida). The difference between th two can be seen at a glance: the state registered boat will have her registration number plainly marked at the bows. I'm a European residing in the US and my boat has the New York registration, since this is where the boat is mainly sailed (if your boat stays more than 60 days in another state, you've got to re-register there). john
Just a cautionary word, they are red hot on the observance of their rules of the road, drinking and speed limits. Transgressions can lead to the instant confiscation of the boat, its equipment and your hire car. Having said that, its a delightfull place to sail or motor. The people are realy friendly and outgoing, and if you take your own red ensign to fly below a Stars and Stripes you will never have a moment without a 'new American friend'.
I have chartered many sailboats, mainly in Florida, and all that is normally required is a resume of experience.
I have had two occasions where I had to take a short 50 question test and one time I had to go with a check out skipper. These are the exceptions however. Do not be afraid to ask a lot of questions about the boats systems as they may not offer to show you where the fuel fill, water fill, strainer and other routinely required devices are located.
