to me "a sailor i am" stresses I, "I am a sailor" stresses sailor, and it is hard for me to know what the author meant, unless by the word order, that is for just a one sentence interpretation .
If what I am hearing (from you) is correct, the correct interpretation may depend on the context of the sentence (in the paragraph)?
This is a beginner text, and I suspect the author is mixing the wording so we (I) will focus on the word endings and practice what is subject, direct object, verb , with proper person, and singular or plural.
I've also noticed there can be a significant difference in supplying "the" or "a" before a word. Nauta scaphas numerat. "the sailor is counting boats", vs. "the sailor is counting the boats." the first implies he is counting boats as they come into sight, the second implies there are a large number of boats in view he is trying to count.
When i get further along, does the word order (or some other clue) in the sentence help with knowing what the author meant? is it the context that supplies the clue? or is it just a best guess interpretation that can vary between translators? [i have basically no experience with foreign languages, and for all i know french or Spanish may have these same problems.]