A Boston Harbor cruise (or Boston Harbour cruise, for our British readers) is either a cruise offered by a company that is actually called “Boston Harbor Cruises” (or BHC), or it is any cruise that takes place in the Boston Harbor. Of course, the cruises offered by Boston Harbor Cruises are in fact cruises that take place in the Boston Harbor, but the point is that BHC does not have a monopoly on these short sailings in the harbor. There are also a number of regular cruises from Boston (i.e., multiple-day voyages offered by cruise lines), but these aren’t really Boston Harbor cruises for reasons we will outline below. Thus, there are Boston Harbor Cruises (with all capital letters) and Boston Harbor cruises (with one lowercase word), with the former being a subset of the latter, and there are also regular cruises from Boston that happen to depart from (where else?) the Boston Harbor. Understandably, you might not have followed all this, so below we explain what Boston Harbor cruises are in greater detail.
There is of course nothing particularly complicated or confusing about what a Boston Harbor cruise actually involves: a cruise in the Boston Harbor. What adds complexity to the situation is that there is, once again, a company that is called Boston Harbor Cruises. So, if someone were to say, “I’m going to take a Boston Harbor cruise,” it would be reasonable to ask this seemingly repetitive question: “Will you be taking a Boston Harbor Cruise or a Boston Harbor cruise?” There is obviously a clearer way to ask this question – “which company will you be taking a Boston Harbor cruise with?” – but we trust you see our point. And in case you don’t, we’ll hammer it home one more time. Imagine there is a pizza company called “Pizza” (for all we know, there is a company that has adopted this audaciously simple name.) When you say “I’m going to eat pizza tonight,” this is ambiguous, as it is not clear if you are referring to any pizza, or to the product of Pizza (which in this hypothetical scenario is just pizza).
The other thing that makes Boston Harbor cruises somewhat complicated is that they must be distinguished from the cruises out of Boston offered by major cruise lines like Royal Caribbean and Norwegian. While these cruises begin and end in the Boston Harbor, it would be strange to call them “Boston Harbor cruises,” as the Harbor isn’t the focus or destination of the voyage. The Harbor is merely passed through en route to some final destination (other parts of New England or Canada, generally).
So, a Boston Harbor cruise is simply a cruise that takes place in the Boston Harbor. It could be offered by Boston Harbor Cruises, or it could be offered by some other company that offer cruises in the same body of water (e.g., Odyssey). These cruises are to be distinguished from the regular cruises that operate out of Boston. With the linguistic matter settled, you can now read about the various Boston Harbor cruises that are available.