Cth yellow, straight down--shall we go?"

"Stop ship," I ordered. "Sound general quarters." There was no
deceleration. We merely swapped ends as the alarm sounded, applied full
power and stopped. That was the advantage of Cth--no inertia. We
backtracked for three seconds and held in middle blue.

* * * * *

"What's going on?" Chase demanded as he came up from below. His eyes
raked the instruments. "Why are we stopped?"

"Disturbance in Cth yellow, sir," I said. "We're positioned above it."

"Very good, Mr. Marsden." He took the spare helmet from the Exec's
chair, clapped it on, fiddled with the controls for a moment, nodded,
and took the helmet off. "Secure and resume course," he said. "That's
the 'Amphitrite'--fleet supply and maintenance. One of our people."

"You sure, sir?" I asked, and then looked at the smug grin on Halloran's
face and wished I hadn't asked.

"Of course," Chase said. "She's a three converter job running at full
output. Since the Rebels have no three converter ships, she has to be
one of ours. And since she's running at full output and only in Cth
yellow, it means she's big, heavy, and awkward--which means a
maintenance or an ammunition supply ship. There's an off phase beat in
her number two converter that gives a twenty cycle pulse to her pattern.
And the only heavy ship in the fleet with this pattern is 'Amphitrite.'
You see?"

I saw--with respect. "You know all the heavies like that, sir?" I asked.

"Not all of them--but I'd like to. It's as much a part of a scoutship
commander's work to know our own ships as those of the enemy."

"Could that trace be a Rebel ruse?"

"Not likely--travelling in the yellow. A ship would be cold meat this
far inside our perimeter. And besides, there's no Rebel alive who can
tune a converter like a Navy mechanic."

"You sure?" I persisted.

"I'm sure. But take her down if you wish."

I did. And it was the "Amphitrite."

"I served on her for six months," Chase said drily as we went back
through the components. I understood his certainty now. A man has a
feeling for ships if he's a good officer. But it was a trait I'd never
expected in Chase. I gave the orders and we resumed our band and speed.
Chase looked at me.

"You acted correctly, Mr. Marsden," he said. "Something I would hardly
expect, but something I was glad to see."

"I served under Andy Royce," I reminded him.

"I know," Chase replied. "That's why I'm s