From all vehicles are only big ships suitable for hydrogen. This is because a tank with 125,000 times more volume has only 2,500 times more surface.
Tanks for liquid hydrogen are extrem insulated. 300 degree Celsius temperature difference have to be as good as possible insulated, to prevent the valuable fuel from
evaporating. But what at a car is a 4 kg hydrogen tank, this could be at a big ship a 500 t hydrogen tank. A 125,000 times bigger tanks has only 2500 times more surface. 500 tons are at 60% efficiency enough to run a 25.000 kW engine for 16 days.
Heavy oil + hydrogen = kerosene
Hydrogen propulsion for large ships. This makes the heavy oil for ships free for other usages. The heavy oil can be refined by hydrogen from solar electric power to kerosene and so make aviation further possilbe.
Political actions necessary
It's not possible to reach such usefull assignment for fuels for different tasks only by price. The heavy oil can not be on the natural way so expensive, that ships prefer hydrogen.
It is necessary to examine this solution for crude oil shortage and to creat political actions.
From liguid natural gas to hydrogen
It should be started today to work on propulsion concepts to propel large ships by natural gas. Engines and tanks should be constructed for the use of liquid hydrogen.