Hydrogen News, page-5091

The shipping industry is rapidly moving towards ammonia as a fuel. In fact just as Gas tankers use the boil off gas to power their own propulsion, you may find that the transport of hydrogen will be in the form of ammonia, and the tankers carrying the ammonia, will also use the boil off gas for their propulsion most likely using Fuel Cells.

You must remember, that you have to get your clean hydrogen from where it is produced to the steel and fertilizer production you speak of. This will also need to be done by ships. so your proposal has the same hurdle to jump - or should I say you have logical contradiction in your argument (which is the usual indicator of lunacy or falsity). Whilst it may not be particularly energy efficient to use Ammonia as a fuel, the shipping industry has little alternative and will adopt very rapidly.