Questão 605302

Towing ships is a dynastic business, hard to

establish and harder still to give up. It's built on

deep allegiance and cutthroat margins, and its

inner workings are full of intrigue and

5 successionary drama: fistfights, lawsuits, power

struggles, and disinheritances.

The early tugs were expensive to staff and

almost comically difficult to steer. A twelve-

hundred-horsepower boat might burn twenty tons

10 of coal in a day and require ten men to shovel it.

Every time the tug needed to reverse direction, the

engine had to be stopped and re-started, by which

point the boat might well have run aground.

Modern tugs are very different beasts.

15 They can have ten thousand horsepower and carry

a hundred thousand gallons of fuel. Their

propulsion systems have evolved from coal to

diesel, from paddle wheel to propeller. Now they

may go five thousand miles without changing

20 course. Then, when things finally get interesting -

when land heaves into view and headlands rise,

when currents intersect and wind barrel down from

surrounding slopes, when a narrow channel must

be negotiated under bridges, between

25 breakwaters, and into a crowded port - the tug

captain assumes control.

The shipping industry has gone on a

construction spree lately, building ships more than

a thousand feet long with as much cargo space as

30 eleven thousand trucks. It means that fewer but

more powerful tugs are required to tow the same

amount of cargo, and shipping schedules have

accelerated dramatically. Tugs that could once

afford to lie at port for a week or two now have

35 turn-arounds of less than twenty-four hours. It is a

new era for tugboats!

(from THE NEW YORKER, April 19, 2010)

In the passage, breakwaters (line 25) means