Who is Rudi Gunn from Raise the Titanic! and what is their importance?

Rudi Gunn was the commander of the Sappho I mission. He has been the captain of every ship in the NUMA fleet. He was on the Sappho I when the cornet was found and was in Sandecker's office for the meeting with the head of the music museum. He is also present at the strategy meeting with Pitt and Sandecker where they decide how to begin the salvage operation. Rudi is there for every step of the operation.