Despite escalating tensions between germany and the u.s. , which by this time had led to a state of undeclared war at sea , still hitler continued to ban any intentional sinkings of u.s. ships .

尽管美德双方的冲突不断扩大升级，但是此时害处为没有宣战的状态，希特勒仍禁止有意击沉美国船只。