Firstly go to the stormworks Steam workshop and search: 1:1 RMS Titanic (Multiplayer Compatible)
subscribe to the ship and spawn it on the custom oil rig using the mission editor, the Titanic's workshop page will probably explain this in more detail.

i love this titanic how do i subscribe so i can spawn it?

Thanks

Its just called 1:1 RMS Titanic (Multiplayer Compatible) on the steam workshop

whats is it?

Yes

is this on the workshop?

𝐆𝐫𝐞𝐚𝐭 𝐣𝐨𝐛! 𝐑𝐚𝐭𝐞𝐝