I was walking through Greenwood Cemetery in Portland Oregon and came across the grave monument of these people. John was born 1872 and Elsie in 1892. The stone says "Were drowned on Princes Sophia."

In the book "The Sinking of the Princess Sophia: Taking the North down with her", there is no biographical sketch of John and Elsie.
Does anyone know if they were from Portland? Or any information on them?

Thank you