(4:07 p.m. EST) - Four passengers and one crewmember have jumped or fallen off cruise ships in the past three weeks. With just 11 reported incidents by the Cruise Lines International Association in 2013, five in such a short time is notable. Here are answers to some questions you might be asking about passengers going overboard cruise ships.

How does someone fall off of a ship?
It is incredibly difficult for a person to fall off of a cruise ship. Railings and guardrails are designed to prevent people who slip, trip or otherwise lose their footing from going overboard. However, passengers who climb on chairs or sit on balcony railings can fall. Sadly, passengers do purposely jump from cruise ships as well.

What happens when an overboard occurs at sea?
If an eyewitness to an overboard alerts the ship's crew that an overboard has occurred, a floating marker will be thrown into the water in the area the person was last seen, and the ship will turn around to return to that area. The ship's captain will contact the Coast Guard, and a search for the person using a tender will be instituted. Also, staff will review onboard security cameras for more information. This is especially true if no one witnessed a missing passenger go overboard. At this point, there is no technology in use on cruise ships that would alert crew instantaneously to a person going overboard.

What is overboard technology?
Using onboard sensors and lasers, overboard technology is designed to immediately alert crew on a ship's bridge that something (or someone) of a significant size has fallen off the ship.

Which ships have that technology?
Cruise Critic reached out to the major cruise lines to find out if any of their ships have overboard technology. Of all the Carnival Corp. brands, only Cunard's Queen Victoria employs a man overboard system, which is being evaluated for reliability. Norwegian Cruise Line and Royal Caribbean Cruises Ltd. declined Cruise Critic's request for information.

Why don't all ships have it?
According to Cruise Lines International Association, the U.S. Coast Guard has not finalized regulations regarding implementation of this technology and claims static land-based systems are not yet reliable in a marine environment. A CLIA spokesman said the industry has been evaluating, testing and conducting trials on man overboard detection systems as it attempts to identify reliable systems since 2006. Carnival Corp's directory of security, Barry Marushi, emphasized the importance of finding a reliable system. "It is important to note that there are significant costs and risks in high false alarm rates to include tying up search and rescue assets, safety of the search and rescue personnel, and operating costs to name a few."

Does anyone survive a fall off of a cruise ship?
People rarely survive falling overboard, but it can happen. Most recently, on October 2012, a passenger fell off a Carnival cruise ship and was rescued.

Are the bodies always found?
No. Most passengers who fall or jump overboard are never found.

What can I do to prevent falling off of a ship?
Be smart. Don't climb or sit on balcony railings; don't climb onto chairs and lean out over a railing (to get a better photo for instance). And, if you plan on over-imbibing, try to buddy up with a sober friend who will make sure you don't do anything foolish.

Why doesn't Cruise Critic cover all overboards?
Covering overboards is a tough decision, and we grapple with each incident we come across. Because many overboards involve people choosing to end their lives or passengers who have acted recklessly, Cruise Critic tries to protect the privacy of the people involved and doesn't cover most overboard incidents. When an overboard is unusual enough to stand out, like the man who fought with security, then grabbed a lifejacket and jumped off his Carnival cruise ship, Cruise Critic does report on the story. Cruise Critic also reports on itinerary changes necessitated by overboards. If a lapse in safety were the clear cause, Cruise Critic would report on the story as well.

--by Dori Saltzman, News Editor