关于non-negotiable B/L与non-negotiable sea way bill的区别

karej

想请教一下老师non-negotiable B/L与non-negotiable sea way bill的区别是什么？
最近看到这句话："the bill of lading, which was stated to be non-negotiable but which nevertheless stated that it had to be presented as a condition of the release of he goods, named Drab as consignee.'可以请教一下老师该怎么理解这句话吗？
一般在CIF contract中的B/L是不是都要求是negotiable 的，如果承运人开出的提单是non-negotiable的是不是就是无效的？
因为是初学，对于提单也不是很理解，所以问题比较多，请谅解！