------were 1316 passengers and a crew of 891

这是倒装句,属于“全部主谓倒装”,即谓语 + 主语.
“部分主谓倒装”形状是 助动词（如have,do）+ 主语 + 动词
这个句子里面
主语是 1,316 passengers and a crew of 891
表语是 were
一般这句话我们会表达成
1316 passengers and a crew of 891 were on board her.
on board the ship 是固定表达.