I received the sad message of the passing away of your dad via Bob Mulder, with whom I worked at Delft University at the time that John prepared his PhD thesis. My sincere condolences to you and your family,

John and I shared a room at the Faculty since it was my task to assist John, if necessary, in completing the Thesis.
Although it seems a long time ago I clearly remember this as an easy, inspiring and pleasant task.
I was impressed by the research work John had already done and I admired his courage to deliver a PhD at an age where others would merely be enjoying a quiet retirement.
Of course we spoke of more things than just engineering and science. Since I am roughly of the same generation as your dad, it was a pleasure to share memories of England and Scotland where I wandered on my bicycle or on foot from the fifties onwards.

.I will remember John as a dedicated engineer and scientist, and above all as a kind and friendly gentleman.

Very best wishes,

Hans van der Vaart