I wonder how difficult it would be use one of these ceramics as ships hull material and what effect such a surface material would have in terms of energy use while cruising at seas.

Fortunately Cerium is the most abundant of the 'rare earths', being about as plentiful in earth's crust as copper, so this discovery may have commercial utility.

Lutetium, erbium belongs into most expensive elements, the export of which is controlled with China in addition. The researchers should make money with research of feasible applications - everything else is a trickery of grant agencies and public, which pays their existence from taxes.

I wonder how difficult it would be use one of these ceramics as ships hull material and what effect such a surface material would have in terms of energy use while cruising at seas.


and

The energy cost of pushing a hull across surface water has much to do with the waves it creates, and far less to do with the boundary layer between ship and water


That's correct. Aside from that, you would need to see how resistant the material is against corrosion in sea water and how it would respond to crustacions like barnacles.

If you are interrested in fuel savings, you might try using something like this in consumer refrigerator and air conditioner compressors/heat exchangers. If you could make even a 1% improvement in the efficiency of those, you'd make a huge impact, as well as a fortune for selling the patent to someone like General Electric.