Okay kiddo, so you know what a big boat is right? Well, some big boats are used for carrying things like toys or food from one place to another. They are called merchant ships. Now, some bad people might try to attack these merchant ships and take away the toys or food. That would be very bad, right?
So, to protect the merchant ships from bad people, they put on special things to make the ship stronger and safer. They add guns, cameras, and special alarms that can tell when bad people are coming. They also put on things like barbed wire fences so nobody can climb on the ship without getting hurt.
This way, if the bad guys try to attack the merchant ship, the ship can protect itself and stay safe. It's like a superhero ship that can protect itself from bad guys and keep all the toys and food safe!