tjs282
Stone \ Cold / Fish
Workers don't have visible HP because they're A.D=0.0, but (the game nonetheless acts as though) they do have 'virtual' HP.A worker in unmodded civ has neither HP nor attack or defence.
Same applies to the A.D=0.0 bombardment-units. You can see this while playing e.g. the Sengoku Conquest: if you have "Animate Battles" switched on when a Ninja Stealth-attacks a bombard-unit sheltering under a unit with A/D > 0, you will see the gunners fire back 3-4 times (i.e. once per each remaining vHP), before the bombard-unit (inevitably) dies.
Not sure whether that 'repeated attack' effect's triggered by the Ninja's Stealth-attack ability, its Hidden Nationality, its Invisibility, and/or some combination of those three. But I'm >99% sure that the Stealth-attack ability is involved (or at least, the fact that the Ninja will not be able to occupy the bombard-unit's tile afterwards), since Ninjas capture Peasant Workers without any difficulty (and the AI uses them for that. All. The. Time).