Indicative be is in free variation with are in King James English

In King James English, both pirates are correct. Be is used with all subjects in the subjunctive (e.g., with if, though, whether, lest. etc.), but in the indicative (i.e., normal sentences), it is in free variation with are. The clearest demonstration of this is this passage from Matthew, which uses both forms within a single verse:

For there are some eunuchs, which were so born from their mother’s womb: and there are some eunuchs, which were made eunuchs of men: and there be eunuchs, which have made themselves eunuchs for the kingdom of heaven’s sake. He that is able to receive it, let him receive it (Matth. 19:12).

Nothing grammatically distinguishes the third bolded phrase from the first two; "there are" and "there be" are interchangeable in the plural.

Here's another pair of examples:

And Joshua said unto the people, Ye are witnesses against yourselves that ye have chosen you the LORD, to serve him. And they said, We are witnesses (Josh. 24:22).

Wherefore ye be witnesses unto yourselves, that ye are the children of them which killed the prophets (Matt. 23:31).

Here's another, spoken by the same people within a single chapter:

We are all one man’s sons; we are true men, thy servants are no spies (Gen. 42:11).

We be twelve brethren, sons of our father; one is not, and the youngest is this day with our father in the land of Canaan (Gen. 42:32).

But you will only find examples like this for be and are -- never for be and is, or am, or art. Indicative be with a singular subject, à la Oscar Gamble, is not the King's English.

I didn't really understand this in childhood, and so when I wanted to write archaic-sounding English, I often used constructions such as "I be Robin Hood" -- which is wrong, though "We be the Merry Men" would have been fine.