The term 'OLD GALLEY' can be broken down into two crossword solutions: BIREME (6 letters) and TRIREME (7 letters). A BIREME is an ancient type of galley ship that was propelled by two banks of oars. It was used by the Greeks and Romans in naval warfare and was typically constructed with a single deck and two masts. A TRIREME is a more advanced version of the BIREME, with three banks of oars and a larger deck. It was also used by the Greeks and Romans in naval warfare and was considered to be a more powerful warship than the BIREME.