Show that this problem is NP-complete

I need some help with the following question.

SHIP LOADING: Given items of weights x1,…,xn, ships of weight
capacity B, can the items be loaded onto C or fewer ships? (All
numbers are positive integers, given in binary.)

Show that SHIP LOADING is NP-complete. (Hint: reduce from SUBSET SUM,
but go through a restricted version where the target b is half the
total.)