Is a ritually impure person’s entry into the sea with the intention of performing ghusl, rubbing the body, and submerging oneself considered a valid ritual bath (ghusl) that permits prayer, and is it sufficient in place of wudu’ (ablution)?

The sufficient act in ghusl from janabah (major ritual impurity) is to generalize water over the entire outer body with the intention. So, if a person immerses himself in the sea with the intention of ghusl, and the water reaches all parts of his body, then his ghusl is valid, even if it is contrary to what is preferable. Imam An-Nawawi mentioned in Al-Majmu' that their madhhab (school of thought) is that rubbing the limbs during ghusl and wudu is a Sunnah and not obligatory, and that pouring water or immersion with the intention is sufficient for the validity of wudu and ghusl. This ghusl suffices for wudu, so a person is permitted to begin prayer immediately after it, provided there is safety from anything that nullifies wudu, with the reminder that touching the male organ does not nullify wudu if it is from behind a barrier.