It was no longer of the least importance to go to the bay.

到海港（这件事）已经变得很重要了
it 形式主语
was 系动词
was no longer是不再的意思
of the least importance是表语 其中least为负面词 与no longer形成双重否定
to go to the bay是动词不定式 作主语
一般语序为To go to the bay was no longer of the least importance.

no longer 不再
of the least importance 最不重要
to go to the bay是真正的主语，前面的it是形式主语。
到海湾去不再无关紧要了。