Sequence of Tenses: Translating the subjunctive

Question

This is probably a pretty basic question, but I am new to Latin and am having trouble understanding the subjunctive.

The sentence "Pūgnāverō ut nautam superem" is translated to "I shall have fought in order that I may overcome the sailor" (according to my textbook). I understand that pūgnāverō is active, indicative, future perfect, first person, singular, which so far I would have believed to be translated as "I will have fought (already)." I am confused because my book uses the word "shall," which to me signals that it is subjunctive.

My questions are:

• Am I misunderstanding the way "shall" is used?
• Is this something that only occurs in clauses of purpose, i.e., is this occurring because "superem" is subjunctive?

There is a similar post here, but I feel it does not answer my question.

Answer 1

You're misunderstanding 'shall.' The traditional convention ('rule') in English is that 'shall' is used with first person subjects (I/we) to form the future and future perfect tenses, whereas 'will' is used for second person (you) and third person (he/she/it/they).* Your textbook is clearly following this convention. The fact that there's also a purpose clause in the sentence has nothing to do with it.

* (Except in emphatic utterances, where the future expresses strong determination to do something; in such cases, 'will' is traditionally used for the first person, 'shall' for the second and third persons.)

Answer 2

The future-perfect is a primary tense for something that has still to be completed; "already" would refer to the past. This is a purpose/ final clause therefore, after ut, the present subjunctive is deployed--superem.