In marine propulsion, what key characteristic of diesel engines was responsible for freeing up valuable cargo space on ships?

Answer

Immense power density.

Marine diesel engines offered immense power packed into a relatively small and light package compared to equally powerful marine steam plants. This high power density freed up valuable cargo space.

In marine propulsion, what key characteristic of diesel engines was responsible for freeing up valuable cargo space on ships?
inventiontechnologyengineimpactRudolf Diesel