Many years ago, (late 80's early 90's?) a guy I worked was researching into hull design for narrow channels, that is narrowboats on canals. I assisted in some measurement of the bow wave. Alvechurch lent us two boats, one with and one without the modified bow. The method of measurement was rather crude but OK for a first look, the "eco" hull gave worse results than the "non-eco" bow. We saw the evidence of improved fuel consumption, why that should be, as far as I can remember, was never discovered.
I think the bulbous style of bow is called "Ostec".
John