Before we left the ship today, we went out on the Promenade Deck to watch a rescue drill from our ship that was taking place. Look closely in the first photo and you'll see the Emerald Princess's rescue boat speeding over toward the Carnival Miracle. 
In the second photo, the rescue craft approaches the life buoy. The rescuer in the front of the boat is giving directions to the pilot. He makes the first attempt to retrieve the buoy; if he misses, a second rescuer is ready to retrieve it.They practice this over and over once a week. If we've been late leaving the ship for the day, we've gotten to see it. It's quite impressive...we have to look hard to even see the buoy in the water.