YOU SAID:

Though my guards may sleep and ships may rest at anchor, our foes know full well that big guns never tire.

INTO JAPANESE

眠り、私のガードも、船がアンカーで休むことがありますは、大きな銃が決してタイヤ我が敵も完全によく知っています。

BACK INTO ENGLISH

Sleep, my guard also ships rest at anchor, the big guns never tire my enemy full well knows.