Going to Cuba as an American, particularly as a part of a rally, is the easiest way to visit. Most crew and boats spend at least a week in Cuba and are free to tour Havana as they wish. They are not required to remain on the boat. You may find the following article (from 2015) of interest.
https://www.waterwayguide.com/latest...el-to-cuba-yes Additionally, you can obtain valuable information regarding cruising to Cuba from the Sarasota Sailing Club.
Unfortunately, those visiting from the USA must buy 'special' Cuban currency which is more expensive than usual Cuban currency. If there is a foreigner (ie. non-American) on board, monetary exchanges are somewhat less exploitative.
The travel insurance requirements do not pose a significant problem as the following official policy explanation shows: Travel Medical Insurance Requirements by Country
Travelers who arrive on the island of Cuba without travel health insurance, or with an invalid travel medical plan, will be able to buy a policy from a Cuban insurance company at the airport, port, or marina where they enter the country.
Travel health insurance recommendations by the visiting country include the following:
For British visitors, the coverage purchased in Cuba is likely to be less comprehensive than most UK-based policies and could have more expensive premiums.
For Canadian visitors, proof of Canadian provincial health insurance is sufficient for entry, but the provincial plan may only cover a portion of the cost of medical treatment and it will not pay the bill up-front and instead require you to pay up front and then claim for reimbursement. It is therefore recommended that Canadians purchase supplemental health insurance for their visits to Cuba.
U.S. residents who are able to obtain a visa, can purchase an insurance policy before they arrive in Cuba or once they arrive in Cuba (at the airport, port, or marina where they enter the country).
In case of any medical emergency, the Cuban health system guarantees the necessary medical care through a network of polyclinics and hospitals, covering every corner of the island. Primary health care is provided in most hotel facilities.