Given how railway staff are highly paid for the sort of jobs they do, whereas ferry staff very low paid, I think they need better unions
That aside, I wonder what the effect on ferries of railway levels of pay would be? Captain only operation* and a lot of automation, I guess? You can only "staff high" in the way ships do if people are cheap.
* Not really, but far fewer crew.
Railway unions work because there is no choice for the employer but to employ union staff. One of the main reasons for the decline in numbers of British Seafarers is union activity in past decades, ship owners just move flags, or go bust when outcompeted by other companies. This is effectively the final play of this trend. Minimum wage legislation really won't help the unions, it'll still be much cheaper to employ non-union seafarers at UK minimum wages than pay RMT rates.
The Nautilus union, which is for officers is much more successful in retaining jobs, largely because it is very non-militant. As a result there is a high demand for UK officers, who are paid very good wages.
Captain only operation is allowed... If carrying up to 12 passengers on vessels less than 24 metres long on inland waterways. Anything else requires a full crew determined by the safe manning document for each ship. Typically for a large ship this would include a Captain, Chief Officer, 2nd officer, Chief Engineer, 2nd Engineer, 3rd engineer, Electrician, Cook and around 6 Able Seamen and a similar number of engineer ratings. A passenger ship would need a larger crew, mainly determined by the emergency response organisation - command and control tam, at least two fire teams, passenger muster teams, medical team, survival craft prep teams etc. There also need to be adequate numbers of qualified people to man the survival craft - typically 5 for a lifeboat and 1 for a raft, plus crew to launch it. On a typical large ferry that probably adds up to 80 people.
I would also be concerned about the fire risk that piling all that flammable stuff up on the car deck might pose.
The car deck is designed for flamable stuff (cars, lorries, hazardous goods etc). It is surrounded by fireproof bulkheads and fitted with goid detection and a very efficient drencher system. Not ideal, but really not a major concern.