What is the ruling on establishing Friday prayer in the sea and prostrating on sand, knowing that the distance covered was not a travel distance?

First: Friday prayer is obligatory for every sane, adult, free, resident, able-bodied male. Traveling before noon is disliked, and forbidden after noon if it leads to missing it. It is not permissible for picnickers and travelers to establish Friday prayer; rather, it is established by permanent residents. If you hear the call to prayer from a nearby village or town, Friday prayer becomes obligatory for you with them; otherwise, you pray Dhuhr.

Second: You are required to repeat the Dhuhr prayer, as your Friday prayer was not valid.

Third: Prostrating on sand is permissible if the worshiper can firmly place his forehead on it and the sand settles beneath it and becomes stable, based on the Prophet's (PBUH) saying: "When you prostrate, enable your forehead to be firm on the ground until you feel the solidity of the earth."