Submarines' Launch Capabilities Critical To Strike Warfare

Since 04-20-03

By Robert A. Hamilton

New London Day

The designation "torpedo tube" might have to be reconsidered on modern submarines.

Navy sources estimate about half of the submarine-launched missiles during the war on Iraq have been delivered via those tubes, matching the number that have been fired from vertical launch tubes, which have been on submarines since 1985.

Aside from exercises, there have been no reported instances of a submarine firing a live torpedo against a target since World War II. For that reason, some fire control technicians have taken to referring to the torpedo tubes as simply "horizontal launch tubes."

Whatever you call them, the vertical and horizontal missile launch capabilities on a modern submarine have made them critical to strike warfare.

The Tomahawk can fly more than 1,000 miles inland and deliver a warhead with a half-ton of high explosive. Despite reports of a few missiles that went awry and landed in neighboring countries, Navy sources said overall those strays represented fewer than 1 percent of the launches, an exceptionally high rate of accuracy.

No matter what type of missile is to be fired, the fire control technicians, or FTs, run through a checklist.

For vertical launch, the FT confirms that the launch capsule is armed, the booster is armed, the interlocks are all closed and the hatch is open.

For horizontal tube launches, the torpedomen must remove a white nosecone with red writing and stripes and the admonition, "Remove before launch," before loading it. Beneath the cover is a black fabric nosecone diaphragm, with the body of the missile in a stainless steel housing that will be left behind at the launch. There is a last-minute review to make sure ballistics are set properly, the weapon is ready, the tube is flooded and the outer door is open.

A series of keys must be turned for each tube - redundancies at each step preclude either an accidental launch or a launch by a single crewman. The executive officer must confirm the right mission has been loaded into the right missile, and the captain gives the final "fire" order.

For a vertical launch, wires send electrical charges to blow up two explosive bolts that hold the missile in place, and to set off a gas generation system that boosts the missile out of the tube and into the air. Before it can begin falling back, the rocket booster lights off and lifts it to cruise altitude, where the booster falls away and its turbo jet engine takes over.

For a horizontal launch, a torpedoman connects a data cable from the tube door to the back of the torpedo, closes the inner hatch and hangs a small sign on the door, "Warshot loaded."

When the order to launch is received, high-pressure air is forced into a reservoir of water, which surges into the torpedo tube behind the weapon and pushes it out of the tube.

As it exits, a lanyard attached to the back of the missile serves two purposes: it yanks it into a vertical position, and pulls a switch that ignites the rocket booster underwater. The water in front of the submarine glows eerily as it is lit by the fire of the propellant burning.

As the missile breaches the surface, a protective sheath peels away at low altitude, and at cruise altitude the booster falls away and the ramjet motor takes over.

Both types of launches shake the entire submarine and fill sailors' ears with the clank of metal-against-metal as the missile exits at several times the force of gravity. It is, submariners agree, something that you cannot replicate outside of combat.

"I've seen videos, but it doesn't really capture what we saw and felt tonight," said Electronics Technician 2nd Class Peter J. Koester on the first night that the Groton-based USS Providence fired in the Red Sea. "There's something different about being here live."