YOU SAID:

the ship went up and down on a wave of bread

INTO JAPANESE

船はパンの波の上を行ったり来たりした

BACK INTO ENGLISH

The ship went back and forth on the waves of bread

INTO JAPANESE

船はパンの波に乗って行ったり来たりした

BACK INTO ENGLISH

The ship came and went on the waves of bread

INTO JAPANESE

船はパンの波に乗って行き来した

BACK INTO ENGLISH

Ships came and went on waves of bread

INTO JAPANESE

船はパンの波に乗って行き交う

BACK INTO ENGLISH

Ships come and go on waves of bread

INTO JAPANESE

船はパンの波に乗って行き来する

BACK INTO ENGLISH

Ships come and go on waves of bread