I know that Dutch people are allowed to sail to Cuba, just do not go to the USA first (as a departing harbour).
Also be prepared to fill out a sh*tload of paper are have a lot of patience with all the bureaucrats.
A sailing instructor I've had the pleasure sailing with has done it.
As in so many things, you're on your own. Most people think it's offensive for a government to tell its citizens where they may or may not go in the world. Land of the free?
I am not aware of any other countries that have the kinds of trade restrictions with Cuba that the US has. Also, as far as I know, there is no restriction on visiting Cuba - only a restriction on trading. So theoretically you (I assume you are a US citizen, living in Illinois) might be allowed to go, but you wouldn't be allowed to engage in any commerce - you wouldn't be allowed to pay for a marina or mooring, buy food or fuel, have a meal in a restaurant, or even buy a pack of gum. And although these rules might have been somewhat ignored in the past, I believe the current administration takes the issue a lot more seriously.
As for non-Americans, I believe it is OK to visit, but may not be OK to travel to/from US directly to/from Cuba.
All of this is just what I understand as gleaned from the internet and reading various articles - no personal experience myself.
I have been there a year ago (not by boat). Except custom bureaucracy on the entering nothing else. Fantastic country with fantastic people. No criminal on street . Music on every corner and good Mojito everywhere.
Castro regime have only one good thing......preservation of 50s!
I visited a lot of destinations .Cuba is one to go back once again!
I believe Americans CAN sail to Cuba. I've been their by plane and have the intention of going back by boat. Surfing I have found accounts of American flagged vessels conducted by Americans sailing over for a short trip. I think you only need clearance from the coastguard. Regarding Castro and his politics there is alot to discuss, I found many more happy faces in Havana than in New York, LA, London, Paris, Rome or anywhere I have been. Its a question of values. As a sign in Havana says "20 million children will sleep on the world's streets tonight - not 1 is Cuban". We democrats are always beating up Castro for the lack of free press but do we have free press? Didn't Israel arrest western journalists - and the US didn't beat them up. Hypocrits. If Cuba is starving to death, that's US foreign policy that is to blame not Castro. Amazing place, wonderfull people - Viva la rivoluzione.
i think nigel calder has written the cruising guide to cuba. worth checking noonsite for further information. holiday in cuba this spring very hospitable. may canadians. didnot see many facilities for yachts