knowing the fathers/son name combination should really help with the census searches when they come online.
The shipbuilder occupation should also narrow things down a little - about 17 counties have sea coasts, with the major ports and possible locations of shipbuilders being Belfast, Dublin, Derry (Foyle shipyard) and Cork/Cobh - other places like Arklow, Waterford and Galway could also be worth checking out.
Shane