в past форме it was a nice afternoon last summer and Paul and Andrew (sail) for a week in the Mediterranean. The two friends ( plan) the sailing trip for months. They (sail) for over two hours when black clouds (appear) in the sky.

it was a nice afternoon last summer and Paul and Andrew  sailed for a week in the Mediterranean. The two friends  planed the sailing trip for months. They sailed for over two hours when black clouds appearred in the sky.