I have never seen "The Good Ship Venus," in any quality source, described as a chanty.

Cray, etc. show that bawdy subject matter appears across the genres of English language song. In my opinion, there is nothing significantly bawdy about chanties as a genre. That is, singers sometimes or often -- depending on one's interpretation -- indulged in creating bawdy lyrics, but this is not a feature that distinctly characterizes chanties.

There are of course a number of distinctly bawdy songs that were enjoyed by sailors as well as by hillbillies in the Ozarks. But those songs don't tend to represent the chanty genre well.

Creators of popular media and some Folk Revival performers, wanting to have some fun and to imagine sailors as exceptionally crude, and to imagine ~all~ sailors' songs to be chanties (I guess the word has a special ring to it?) may have indulged in selectively presenting a few bawdy songs as "typical" of sailors' songs AKA (in their mind) "chanties."