Although easy on the eyes when viewed through a snorkeling mask, coral reefs aren't so easy on hull of your vessel, causing extreme amounts of damage in the case of collision.
Trade winds sweeping in from the Atlantic can often bode ill for your Caribbean voyage, often bringing tropical storms along with them. Also, from June until November, the possibility of hurricanes and tropical storms throughout the Caribbean is very real. At the height of a hurricane, the last place you want to be is at sea.
Pulling into harbor always opens a new range of possible dangers. Depending on your port of call, these could include local crime, unavailability of food or water or risk of disease.
Although ringing of a time long gone, pirates continue to pose a threat to small vessels sailing in the Caribbean, occasionally boarding and looting without regard for the safety of the passengers.
When taking on the Caribbean in a sailboat, always check the extended forecast and arm yourself with a marine VHF radio, life jackets, flares and reliable ocean maps. Also, make sure your emergency equipment is easily accessible in case of an immediate threat.