Al,

>I'm assuming you're measuring efficiency as energy used per tonne-kilometer of goods moved. Ships are very good.

Not really. The diesel fuel is burned (loss #0 because the fuel isn't 100% oxidized) in a piston based engine (loss #1 primarily frictional losses) which drives an electrical generator (loss #2 you can't convert mechanical energy to elecrical energy at a 100% rate) which powers an electrical motor (loss #3 you can't convert elecrical energy to mechanical energy at a 100% rate) which spins a prop (loss #4 frictional loss) which causes water displacement without 100% efficiency (loss #5 frictional loss).

A jet engine burns the fuel (loss #0 because the fuel isn't 100% oxidized) which drives a turbine (loss #1 this energy is intentionally extracted to drive the compressor on the shaft to compress the incoming air).

>As for jets - if they were so efficient, we'd be shipping grain and coal by jet ;)

Fuel efficiency is only one factor, and for most of the stuff transported by ship and rail there aren't other viable options.