in 1881 census
Onchan 13 Hanover St RULER John J. Head M M 44 Engine Driver born Douglas IoM
Onchan 13 Hanover St RULER Margaret Wife M F 36 Engine Driver Wife Douglas IoM
Onchan 13 Hanover St RULER William J. Son U M 14 Tobacconist Douglas IoM
Onchan 13 Hanover St RULER Mary A. Daur U F 11 --- Douglas IoM
Onchan 13 Hanover St RULER John J. Son U M 7 Scholar Douglas IoM
Onchan 13 Hanover St RULER Robert J. Son U M 3 --- Douglas IoM

The engine driver could have been on board a boat, a mine/factory or possibly the railway (though for most railway employees they stated 'railway engine driver'

Mariner = someone employed full time on board a boat - anything from a fishing vessel (though generally such described themselves as fishermen, the steam packet vessels or coastal traders etc)

in 1837 Ruler Eleanor, Strand st was a bathing machine keeper - can't find any other 'Rulers' in my victorian directories