I tied my boat to a tree so that it won't get washed away.
"海にボートが流されないようにロープでボートを木に結んでる" は英語で
- I tied my boat to a tree so that it won't get washed away.
といえます。
ボートが流されないよう
- so that the boat won't get washed away
- so that the boat won't get swept away
- so that the boat won't get carried away (by the waves)
海には波があるからボートが波に持っていかれる。そうならないように海辺の近くにある木にボートを縛っておく
Since oceans have waves, the waves can carry the boat away. In order to prevent that, I tie the boat to a tree near the beach.