Many years ago I was sat in a class at college doing a subject called Tribology, which is the science of how surfaces react and respond to each other and how lubricants affect this relationship. The science of lube oils is not far off the mark.
Anyway the guy asked the class what people popping thier fingers had in common with erosion of a propeller and, I have no idea why, I saw the connection, stuck up my hand and said "cavitation".
The fact that I was correct has stuck in my mind ever since! (Maybe it was rare!)
I agree with your thoughts on the cool subjects. Propeller design is an unbeleivably complex subject and yet most of them are, at the best, a compromise and, at the worst, such as controllable pitch props, bloody inefficient!
As with a lot of things though the really interesting, more traditional stuff is dying out as more and more technology takes over and the intervention of the engineer with his thought process is less and less of a requirement.
Only the other day we had a problem to solve whereby we wanted to remove a section of main seawater pipe, 4 foot diameter, and fit blanks but we could not get an effective isolation. The Deputy Chief suggested we run a pump on the line to vacate the line while we fitted the blanks. It worked and we saved ourselves a very big job. It is just this sort of thinking that we are loosing as technology takes over and we become isolated from the hardware that is working for us.
I agree though, I still enjoy playing around with traditional Marine Engineering concepts and the appliance of things I learned at college that I never thought I was going to use.
