ULA Class Diesel Electric Submarine

The diesel engine developed exponentially at the turn of the 20th century because it was used in an extreme applicationpowering submarines. German U-boats, although small in number compared to the massive Allied shipping effort, dominated the seas during much of World War II. During the Cold War, nuclear submarines made diesel-electrics pretty much obsolete because of their ability to stay under water with no need for air or refueling. Today, the battlefield has changed once again and diesel-electric submarines are making a comeback.

Ula Class Submarine

The Royal Norwegian Navy commissioned six Ula Class submarines 20 years ago. An April ’08 report by National Defense magazine quoted Guy Stitt, president of AMI International, a Bremerton, Washington-based company specializing in naval market analysis, as saying, The beauty about a diesel submarine is that it has the potential to be far quieter than a nuclear submarine.

Diesel-electric submarines also cost much less, which is appealing to many countries that don’t have a nuclear budget. Plus, if a diesel-electric sub goes down or is captured, it is not as hurtfultactically speaking. Although a diesel-electric submarine doesn’t have the underwater endurance a nuclear submarine offers, military leaders are finding this metric isn’t as crucial in an age of multilateral terrorism. Battles are now fought in shallow waters, instead of the deep-sea American and Soviet sea wars of the past.

Diesel-Electric Versus Nuclear

Today’s diesel-electric submarines are light-years ahead of the clanking U-boats we see in old war movies. Although, the basic principle is still the same: The diesel engine is used at the surface to charge electric batteries, and then an electric motor powers the submarine under the water. Some of these new diesel-electric submarines have improved air-independent propulsion systems that use cryogenically frozen oxygen and exhaust gas recirculation (EGR) to create their own atmosphere under the water. Fuel cells and sterling engines are also used on some models. These upgrades allow the diesel-electric subs to creep along in coastal waters, which are very hard to patrol because of noisy sea creatures, boat traffic, and sonar limitations (due to its damaging effects on animals).

Considering the current state of world conditions, perhaps we’ll see a real-life version of the movie Down Periscope, starring Kelsey Grammer, in which a ragtag team and an old diesel sub trumped the newest, most expensive, nuclear version?

MIL-SPEC: Ula Class Submarine

Manufacturer:Kongsberg and Thyssen Nordseewerke

Vehicle:Ula Class submarine

Length:194 feet

Beam:18 feet

Draft:15 feet

Propulsion:Diesel-electric

Diesel engines:Two MTU 16V396, 90-degree V-16s

Displacement:3,868 cubic inches (63.4L)

Horsepower:More than 1,300 hp each

Bore:6 inches

Stroke:7.3 inches

Electric motor:6,000 hp

Surface speed:11 knots

Submerged speed:23 knots

Range:5,000 miles at 8 knots

Maximum operational depth:700 feet

Armament:Eight bow 21-inch torpedo tubes and 14 torpedoes

Crew:21 people

Endurance:Approximately 30 days