In normal times, crewing the world's merchant fleet is a logistical miracle.

平时，在世界商船队工作是一个物流奇迹。

A strong merchant fleet meant lots of boats that could be commandeered during times of war.

一个强大的商船队意味着战争时期可以征用更多的船舶。

By extension, Mahan also sought a larger merchant fleet to carry goods from American factories to foreign lands, and for a larger Navy to protect that merchant fleet.

此外，马汉还寻求建立一支更大的商船队，将美国工厂的货物运往国外，并建立一支更大的海军来保护这支商船队。

The Romans lost their African jewels, and the Vandals gained  most of the African merchant fleet and shipyards.

罗马人失去了他们的非洲珠宝，汪达尔人获得了大部分非洲商船队和造船厂。

(Explosion sounds) Then,there's the sound of the actual drilling for oil and gas, the construction of things like offshore wind farms,sonar and of course, the nearly constant drone from more than 50,000 ships in the global merchant fleet.

（爆炸声）然后是石油和天然气实际钻探的声音，海上风电场、声纳等建设的声音，当然还有全球商船队 50, 000 多艘船只几乎不间断的无人机。