We unloaded cargo, reloaded with something else, then again we put to sea in the routine familiar to us, and as the days became weeks, my little personal experience receded. Sometimes, when we were at sea, a mail ship would rendezvous and bring us mail from home, which, of course, we accorded topmost priority.

很简单啊

整个句子是由and引导的两个并列句，和sometimes 引导的一个时间状语从句。第一个句 and 结构前，unloaded, reloaded 和 put为三个并列谓语，familiar to us 作 routine 的定语，为“形容词短语作定语”结构；and结构后的句子中，as the days became weeks，是时间状语。最后，在sometimes后引导的状语从句中，又嵌套着一个非限制性定语从句，主语为 a mail ship，在which引导的非限制性定语从句中，mail 又作accorded的宾语。这就是整句话的语法结构分析~希望对您有帮助~