​Centuries ago doing the time of Noah; God send a worldwide flood on the earth to wipe out all life. God did so because the evil of mankind was very great. Genesis 6.5-7:12-13.
 
God was so determined that there be no survivors; He caused the flood waters to rise higher than the tallest mountains on earth. Genesis 7:17-24. And if there could have been satellite photos of the earth, no land would have been seen, only a big globe of water.
 
Out of all the people living during that time, only the house of Noah was considered righteous in the eyes of the Lord. Genesis 6:8-9.
 
In order not to kill Noah and his family along with the rest of the earth; God devised a plan to preserve Noah. That plan was in the form of the ark; a boat designed by the Lord himself which would be capable of sustaining life and would be able to stay afloat during this awesome flood.
 
If one were alive back then, the only way to survive the flood would have to be inside the ark. The ark was the only place of salvation and even if there were cruise ships available; they wouldn't be able to withstand the flood. The reason? They aren't the ark. Only the ark was the place of salvation; no other boat would do, because those boats weren't designed by God.
 
God personally shut the door of the ark, locking Noah and his family inside so they wouldn't suffer from the rain falling upon the earth. Gen 7:17-18.
 
God wouldn't lock the doors of a cruise ship had one been available. The cruise ship hasn't been authorized by God and has no salvation from the flood, therefore all aboard would drown when the cruise ship sinks.
 
Remember Psalms 127:1. Unless the Lord builds the house, the builders labor in vain. Unless the Lord watches over the city the guards stand watch in vain.