Final answer:
The ship in The Rime of the Ancient Mariner couldn't sail further after entering the Pacific because the wind died down, leading to a motionless state in the water that prevented its progress.
Step-by-step explanation:
In the poem The Rime of the Ancient Mariner by Samuel Taylor Coleridge, after the ship entered the Pacific Ocean, it could not sail any further because the wind died down. This loss of wind left the ship becalmed, leading to a stillness on the water that prevented the ship's progress. The conditions become debilitating for the crew, leading to thirst and despair. This circumstance is a pivotal moment in the poem that contributes to the deeper themes of nature's power over man and the consequences of the mariner's earlier actions.