There you go, I'll give you a point for that. 1 point.

I've read they were used to collect garbage. I'd thought
that garbage was simply tossed in the sea in the old days,
but perhaps not in port.

I would think the nearest analogy would be a "pump-out" boat.
They are common in Connecticut.

katysails wrote
Honey barge is a floating vessel used to pump human waste from ships just
like a honey wagon is a septic tank truck....