If you are concerned about the general cleanliness of a cruise line, check out the Center for Disease Control's cleanliness ratings from the CDC web site, http://www.cdc.gov/travel/travel.html.

The rules for safety on ships are similar to those on land: 

• Put any valuables in the ship safe. 

 
• Use dead bolts on the front and side adjoining cabin doors.

 
• Don't leave cabin keys on your towel while you swim. Check them with the steward.

 
• Pack clothing for all weather. No matter what time of year you are traveling, remember to use sunscreen.

 
• When you go ashore, stick with a guided tour. If you're on your own, ask the crew which areas of town you should avoid. Remember that crime never takes a vacation.

 
• If you engage in water sports like jet skiing, be sure that you know how to operate the watercraft safely. Is the equipment in good condition? Wear a life jacket. If there are others who are acting unsafe, don't go in. Never engage in water sports alone, during a storm or under the influence of alcohol.

 
• Always participate in life boat drills. Make sure you know where your life jacket is and how to put it on. 

 
• Remember to bring your prescription medications. Bring more than you will need, in case your cruise gets delayed in a remote location.

 
• Know the emergency exits and study the fire escape plan. If you are traveling with someone who needs special assistance, let the crew know.