Suddenly "boat" is an acceptable translation for hajó whereas in previous translations it has been marked wrong? I know there is a technical difference in English but can a native speaker comment on whether there is a difference in Hungarian?
Excellent that gives me a very clear picture of what the different words mean to you!
I think boat should definitely be accepted for hajó. In English, there isn't a firm distinction between ship and boat, but I think Shamarth's middle example might count as a boat.
Would it be incorrect to call the rowboat and motorcsónak as hajó?
Animals can't board a ship? Hajó necessarily means something big, so I think it couldn't be a boat, it should be ship.
"Animals get into the boat, too," not a good translation? I was under the impression that preverbs perfected verbs, or is that not the case with "be-"?
"Animals are also boarding the ship"
This (or similar) should be the default translation. Getting on / getting in / boarding are all equivalent in this case. However, "getting in" seems least likely as you would "get in" a small boat, but "get on" or "board" a large boat or ship.
The "too" at the end of the sentence is too repetitive for Duo to so frequently use, and also unnatural in this case.