It was the navy's Fleet Week.
The bay was full of ships for people to see and visit.
Orson stood with his cousin Nick on top of a long black submarine.
Nick was a sailor who worked aboard this underwater vessel.
"What does this submarine do?" Orson asked.
"The navy uses submarines to help protect our country," Nick said.
"Most of our missions are for military research. Ready to see inside?"
Orson shivered. The sub had no windows.
It seemed scary.
Nick climbed down the ladder inside the hatch, the round opening that led into the sub.
"Come on down," he called.
Orson cautiously stepped onto the ladder's first rung.
"Will the sub sink while we're on board?"
"Subs control when they submerge," Nick assured him as they climbed down the ladder.
"Tanks filled with air help them float.
To submerge, we pump water into the tanks.
That makes the sub heavier, so it goes down."
"How does it get back up?"
"We fill the tanks with air again to make it float."
Nick grinned at him. "We won't submerge today."
Orson reached the bottom of the ladder.
"Why is it so cramped in here?
The sub looks huge on the outside."
"Nuclear subs are big.
This one is over ninety meters long, but the power plant and equipment take up most of the space," said Nick.
"The 135 crew members get any room that's left."
He laughed. "Some subs, like the ones they use for scientific research, are powered with oil.
Oil-powered subs must surface every few days.
Nuclear subs can stay underwater for months."
"Don't you run out of water and air when the sub stays underwater that long?"
"We make our own fresh water and air."
"We made fresh water in school!" Orson said.
"We boiled salt water and saved the condensed steam. Is that what you do?"
"Exactly," said Nick.
"We make enough water for crew members to drink and take a three-minute shower every day.
Most of the water, though, is used to cool equipment."
"How do you make air?"
"We take oxygen from water.
And we can reuse existing air by getting rid of the carbon dioxide people breathe out."
"Cool," Orson said.
Nick led Orson through rooms filled with computers.
"We navigate with GPS on the surface, but GPS doesn't work underwater.
So we navigate by keeping track of our direction and speed."
"How do you keep the sub from crashing into things?"
"We use sound. We listen for sounds from other ships.
We also use a device called sonar.
It bounces sound off objects to detect and locate them."
"That's what dolphins do!" Orson said.
They climbed down a narrow stairway.
Here beds were stacked three-high along the walls.
"This is the crew's quarters."
Nick pointed to a small drawer under one bed.
"I keep all my stuff here."
"Everything?" Orson had a room full of stuff at home.
"What do you do all day?"
"I'm on watch for eight hours.
That's when I'm helping to operate the sub.
When I'm not on watch, I still have to work to help clean and maintain the sub.
We get some free time too.
Then I sleep for eight hours."
Suddenly the sub rocked.
"Whoa!" Orson said.
"Don't worry," Nick said.
"Waves rock subs on the surface, but it's smooth sailing underwater."
"I believe you." Orson smiled.
"Living underwater seems like living in a spaceship!
But I think I like living on land better!"