Invisible Stars - GPS Declassified: From Smart Bombs to Smartphones - page 71

tudes at inhabited islands. Early in the voyage Cook wrote, “Mr. Kendall's Watch
thus far has been found to answer beyond all expectations.” 6 About halfway
through the expedition, in January 1774, Cook commented, “Indeed our error
can never be great so long as we have so good a guide as Mr. Kendall's watch.” 7
A Giant Leap
While Captain Cook easily made the transition to using a mechanical time-
piece for determining his longitude instead of measuring the distance between
the moon and stars, the chronometer augmented celestial navigation; it did
not replace it. Even Cook would have difficulty making the leap to our tech-
nology nearly two and a half centuries later. As a thought experiment, imagine
transporting Cook through time to the bridge of a modern Coast Guard cutter
for an introduction to its navigation equipment. His conversation with the
commander might go something like this:
Cook: What a remarkable cabin you have here. What is its purpose? It can-
not be where you sleep. I see no bed.
Commander: No, sir. This is the helm. We steer the ship from here.
Cook: You have built walls and a roof round your wheel? Where is the wheel?
I don't see it.
Commander: We don't use a wheel anymore. We control the rudder with
this. It's called a joystick.
Cook: I am at a loss to understand. How do the boatswains hear your line
commands?
Commander: Well, we make announcements by speaking into this micro-
phone and the sound of our voices comes out of speakers—like horns, you
might say—located all over the ship. We also have bells, whistles, and
lights, but we have no sails. An engine powers the ship, so the boatswains
mates have other duties.
Cook: Engine? You mean the steam invention used for pumping water?
Commander: Yes, a descendant of that. They have advanced considerably.
We don't use coal or steam. Diesel fuel—like lamp oil—powers our engine,
which turns a ten-foot propeller.
Cook: Pro- pel- ler?
Commander: It's like a series of oars that turn in a circle—the same principle
as Archimedes's screw. Instead of lifting water, this screw moves us
through it.