Read first “The new age of sail”
Just an idea:
Perhaps that a prize should be organised, or a contest, for the most fuel efficient transport ship, with two different categories: Above the surface and below the surface. This to allow for submarine desings as well.
Different classes could be used, for those delivering express goods, and for those that ship bulk goods. Several categories could possibly be added as well: coastal waters, open oceans, and river transports.
This to sponsor novel desings, or redesings. Not all desings will work everywhere, so a price per category would need to be added.
With one exeception: no nuclear fueled ships allowed.
A contest like this, migth produce more efficient ship designs, and would give a reason to do so. A bit like the contest about the fastest cross of the atlantic ocean.