ان النبى صلى الله عليه وسلم امره ان يصلي فى السفينة قائما الا ان يخشي الغرق
"The Noble Prophet (peace and blessings be upon him) instructed Hazrat Ja'far (may Allah be pleased with him) to perform prayer standing on the boat, except if there is a fear of drowning (then permission is granted to pray while sitting)."