[aetherson]

Shipping by container ship is already pretty cheap, and of course shipping isn't itself a good that people care about, it's a way to get some other good. It also seems like the supply bottleneck for shipping per se is probably more "number of ships" or "capacity of ports and big canals" than "fuel costs."

We should of course assume that ceteris paribus lower shipping costs produce more shipping on the margin, but I don't see a lot of reason to believe that this is the major supply bottleneck for most goods. I wouldn't expect to see a dramatic change in demand for shipping as a result of 20% lower fuel costs.