I recently came across a book "The Canadian Submarine Service in Review" by David Perkins, published in Canada in 2000, and looking through I came across a familiar name, and realised that I had in my collection of R.N. Deaths in WW1, a cover from this officer, A/Lieut W.M. Maitland-Dougall, RCN, to his mother in Canada, also there is a photograph of him in the book.
The story of her accidental sinking is attached.
Frank Schofield