 Kohler has explored shipwrecks around the world, including the SS "Andrea Doria" and the RMS "Titanic".Diving from the Russian research vessel Keldysh, Kohler made multiple dives to in the MIR submersibles to explore the "Titanic"'s wreck site.Kohler's work identifying a World War II German submarine, U-869, off the coast of New Jersey has been the subject of several television documentaries and a book by Robert Kurson, "Shadow Divers".