偷越

tōu yuè fēng suǒ jiè

偷越封锁界

run a blockade

běi fāng pào tǐng duì nán fāng gǎng kǒu de fēng suǒ yǐ gèng jiā yán mì néng gòu tōu yuè de chuán zhī yǐ hěn shǎo le

北方炮艇对南方港口的封锁已更加严密，能够偷越的船只已很少了。

The Yankee gunboats had tightened the mesh at the ports and very few ships were now able to slip past the blockade.