NNS020807-04 Making Steam for the Scream
Release Date: 8/7/2002 11:24:00 AM
By Journalist 2nd Class Chad Pritt, USS Constellation Public Affairs
USS CONSTELLATION, At Sea (NNS) -- Before the jet aircraft came along, propeller-driven planes would travel the length of an aircraft carrier's flight deck under their own power.
Upon reaching the edge, they would sail into the air gaining speed and altitude without outside assistance. With the invention of the jet, a more powerful method was needed to propel the Navy's war birds off the pointy end of its massive carriers.
The United States began working with the concept of using gunpowder to literally "shoot" planes off of ships before the British stepped in with a different solution: launching the new, heavier aircraft using a steam-driven catapult.
Fifty years later, the same method is used, and it's the melding of two ship's departments that make it possible. Air Department's V-2 division, which controls the arresting gear and catapults, or "cats" for short, and Engineering Department's P-3C division, which monitors the steam systems and makes repairs when needed.
"We make sure [V-2] has enough steam to launch the airplanes," said Machinist's Mate 3rd Class Jeremy Wiggins, a Ringgold, La., native.
Not only does the San Diego-based USS Constellation's (CV 64) Engineering Department produce the steam to get planes into the air, it goes the next step and keeps the steam systems operating properly.
"We do all the preventive maintenance to all cat steam valves," said Machinist's Mate 3rd Class Anthony Karsten, P-3C's work center supervisor. "We have over 70 spaces to preserve and clean, and they're spread out between the fourth deck and the 03 level."
P-3C, or the Cat Steam Shop, has the integral job of monitoring the four steam accumulator bottles; one for each catapult.
"They need to be between 510-530 p.s.i. (pounds per square inch)," said Karsten, a Tulare, Calif., native. "If it's out of range we can't shoot planes off. Not enough and the plane could end up in the water. Too much can result in another casualty of some kind."
Each catapult is directly connected with one of the four main propulsion spaces. One Main Machinery Room (1MMR) provides steam to the number one catapult; 2MMR provides for number three catapult; 3MMR provides for number four catapult, and 4MMR provides for number two cat. However, the catapults aren't exclusively powered by its coinciding MMR.
"Any space can supply any cat," Karsten said. "All we have to do is cross connect the steam lines to the desired holding tank."
To cross connect, a series of valves need to be opened or closed, allowing the steam to take a different path. The ability to do this is very important in a warship such as Constellation, which could suffer a number of casualties during an enemy attack. With this ability, "America's Flagship" can continue to launch aircraft and fight.
With complicated systems such as the steam and catapult systems, it's important to maintain vigil watches. One such watch is the cat steam supervisor. It's this watchstander's job to keep an eye on the main steam line and prevent it from dropping below the 1,200 p.s.i. level.
"The cat steam supervisor can also call Damage Control Central (DC Central) in the case of a main steam loss," Karsten said. "He also acts as a liaison between Air and Engineering. He gets permission from Central to launch, tells the cat operators they have permission, and then the operator tells V-2."
These lines of communication work just as well in reverse if necessary.
"The cat operator will tell the supervisor they're getting ready to launch, and the supervisor tells the main space so it knows they're going to take steam from the accumulators," Karsten said. "This is done for each launch."
|Join the GlobalSecurity.org mailing list|