体积比重量，就是积载因数

   货物记载因素：每一吨货物在正常堆积时实际所占的容积（包括货件之间正常空袭以及必要的衬隔、铺垫所占的空间）。其单位为立方米/吨或者立方英尺/吨。
   简单的说，就是一楼说的，体积比上重量，不过，要注意单位换算。 

Stowage factor is normally given by charterer or port terminal for pre-stowage plan calculation . But please remember SF given by party concerned is a estimated figure , in fact nobody knows actual SF for a specific ship . Experienced Master and his mate know how to deal with this matter .