The Prophet ﷺ said: No one should sail on the sea except the one who is going to perform hajj or umrah, or the one who is fighting in Allah's path for under the sea there is a fire, and under the fire there is a sea.  

قَالَ رَسُولُ اللَّهِ ﷺ لاَ يَرْكَبُ الْبَحْرَ إِلاَّ حَاجٌّ أَوْ مُعْتَمِرٌ أَوْ غَازٍ فِي سَبِيلِ اللَّهِ فَإِنَّ تَحْتَ الْبَحْرِ نَارًا وَتَحْتَ النَّارِ بَحْرًا