Jihad at sea

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: Once the Prophet (peace and blessings be upon him) was in the house of one of his wives. He laid down his head and fell asleep, and during his sleep he kept smiling. When he woke up, his wife said to him: "You were smiling in your sleep; what made you smile?" The Prophet (peace and blessings be upon him) said: "I was pleased by some people of my Ummah who will ride upon this sea, going around the enemy; they will strive in the way of Allah." The narrator says: After that the Prophet (peace and blessings be upon him) mentioned much good for those people.
Ahmad recorded it. Its chain contains a narrator, Muhammad bin Thabit al-Abdi; according to one report Yahya bin Ma'in declared him thiqah (trustworthy), and al-Nasa'i (may Allah have mercy on him) did likewise. The rest of its narrators are thiqat (trustworthy).

Sayyiduna Abdullah bin Amr bin al-As (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "For one who has not performed Hajj, performing Hajj is better than taking part in ten military expeditions; for one who has already performed Hajj, taking part in an expedition is better than performing Hajj ten times; taking part in an expedition at sea is better than taking part in ten expeditions on land. Whoever crosses the sea is as though he has crossed all the valleys, and the one whose head spins (on a sea voyage) is like one who is soaked in his own blood (in a battle on land)."
Al-Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat. Its chain contains a narrator, Abdullah bin Salih, the scribe of al-Layth. Abd al-Malik bin Shu'ayb bin al-Layth said: He is thiqah ma'mun (trustworthy and reliable); others besides him declared him da'if (weak).

Sayyiduna Imran bin Husayn (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever takes part in one sea expedition in the way of Allah - and Allah knows best who is fighting in His way - such a person has rendered to Allah Almighty all of his obedience, has sought Paradise in every way, and has fled from Hell in every way."
Al-Tabarani recorded it in all three books. Its chain contains a narrator, Umar bin al-Subh, who is matruk (abandoned).

Sayyiduna Wathilah bin al-Asqa' (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever was unable to take part in fighting with me should take part in an expedition at sea."
Al-Tabarani recorded it in al-Mu'jam al-Awsat. Its chain contains a narrator, Amr bin al-Husayn, who is da'if (weak).

Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrated this as a marfu' hadith (attributed to the Prophet): The Prophet (peace and blessings be upon him) said: "Allah Almighty spoke to the western sea and spoke to the eastern sea. He said to the western sea: 'I will make some of My servants ride upon you; what will you do with them?' It replied: 'I will drown them.' So Allah Almighty said: 'Your harm will be in your surrounding regions,' and Allah Almighty deprived it of ornaments and game. Then Allah Almighty spoke to the eastern sea and said: 'I will make some of My servants ride upon you; what will you do with them?' It replied: 'I will carry them upon my body, and I will be for them as a mother is for her children.' So Allah Almighty rewarded it with ornaments and game."
Al-Bazzar recorded it as a wijadah (a narration taken from a written source). Its chain contains a narrator, Abd al-Rahman bin Abdullah bin Umar al-Umari, who is matruk (abandoned).

Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates that the Prophet (peace and blessings be upon him) said: "Board the sea only to go for Hajj or to take part in fighting."
Al-Bazzar recorded it. Its chain contains a narrator, Layth bin Abi Sulaym, who is a mudallis (one who conceals defects in the chain). The rest of its narrators are thiqat (trustworthy).