Prayer on a Ship
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 62
وَ سَأَلَ عَلِيُّ بْنُ جَعْفَرٍ أَخَاهُ مُوسَى بْنَ جَعْفَرٍ عَلَيْهِمَا اَلسَّلاَمُ عَنِ اَلرَّجُلِ يَكُونُ فِي اَلسَّفِينَةِ هَلْ يَجُوزُ لَهُ أَنْ يَضَعَ اَلْحَصِيرَ عَلَى اَلْمَتَاعِ أَوِ اَلْقَتِّ وَ اَلتِّبْنِ وَ اَلْحِنْطَةِ وَ اَلشَّعِيرِ وَ غَيْرِ ذَلِكَ ثُمَّ يُصَلِّيَ عَلَيْهِ فَقَالَ «لاَ بَأْسَ.
Ali ibn Ja'far asked his brother Imam Musa ibn Jafar Al-Kadhim عليه السلام about a man on a ship: Is it permissible for him to place a mat over goods, straw, wheat, barley, or other items and then pray on it? Imam عليه السلام said: "There is no harm."
- Ṣaḥīḥ al-Faqīh, p. 67