surface tail configuration and gives the impression of six thin, flat 'fin stabilizers' jutting from the aft of the boat, which face out at varying angles from the shrouded prop. Fitted to the stabilizer at the four- and eight-o'clock positions are shrouds through which the sensitive TB-16D and TB-29 towed array sonars are streamed out from the boat. As you move around to the sides of the lower hull, you'll notice one of the biggest advances perfected between the construction of the last of the 688I boats and the new Seawolf. This is the addition of the BQG-5D Wide Aperture Array (WAA) system sensor fittings. Although invisible when the sub lies in the water, the WAA is one of the most distinctive features of this revolutionary warship design. An advanced passive sensor system fitted into three rectangular housings attached to each side of the lower hull, the WAA performs an essential mission when the boat is in the detection and tracking phases of an engagement, and Seawolf is the first full class of submarines fitted with the system. The WAA has been so successful in trials that plans currently call for fitting it into the future Virginia (SSN-774) class as well.
In the bow is a large, 24-foot/ 7.3-meter-diameter spherical sonar array, which is the heart of the BSY-2 combat system. Based on the earlier BSY-1 system we showed you aboard Miami, BSY-2 is, in terms of software, processing power, and integration, a generation ahead of the earlier system. By tying together all the various sonar and other sensors systems into the BSY-2, Seawolf has a capability for multitarget combat engagements and situational awareness matched only by the Aegis combat system on the Ticonderoga (CG-47) and Arleigh Burke (DDG- 51) missile cruisers and destroyers.
As we continue along our journey on Seawolf, you'll notice many bulges and bumps along the hull, each of which serves a vital purpose. Walking along the long hull, which is 353 feet/107.6 meters long and 40 feet/12.2 meters wide, you'll see a long, thin faring that is raised several inches off the deck. This is where the towed array sonars are stored. Also, as during our visit to Miami and Triumph, you'll notice that the deck is made of a thick, spongy coating known as anechoic tiles. These black rubberlike tiles do much to seal sound inside the Seawolf as well as keep other sounds from bouncing off the boat and reflecting sonar 'pings' back to prowling surface ships, sonobouys, or enemy submarines. Every now and then you might see a submarine, especially those of the former Soviet Union, missing a tile or two. These occasionally fall off and make for some interesting photo ops!
Navy and contractor personnel man the underway main control watch, aboard Seawolf. OFFICIAL U.S. NAVY PHOTO Underneath the tiles is one of the hardest steel hulls ever constructed on an American ship. Once the welding work of Seawolf was fixed, the real benefits of HY-100 steel became apparent. With a significant (meaning classified) increase in diving depth over the 688I class, Seawolf is able to operate farther into the ocean depths than any attack submarine in American history. This has restored much of the tactical capability lost when the HY-80 hulls of the Los Angeles- class boats were thinned down to save weight and displacement. As the recent loss of the Russian submarine Kursk illustrates, the ocean depths can be anything but hospitable, and the deeper a submarine goes the more pressure is exerted on its hull. It was just these dangers that the submarine designers had in mind when they built in the next feature we run across as we tour Seawolf's deck- the submarine escape trunk and Deep Submergence Rescue Vehicle (DSRV) mating hatch.
This aft hatch, along with a second hatch farther forward, is where a rescue chamber or submarine like the DSRV would mate with Seawolf in the event she suffered a catastrophic accident and the crewmembers were still safe. This is, of course, a really big if. It is, however, a very real possibility that was demonstrated quite sadly by the loss of the Kursk and her crew in 2000. A number of the Kursk's crew survived the sinking of their boat and might have been saved had their government allowed U.S. or British DSRVs to be deployed earlier during the search-and-rescue operations.
There have been some changes in the field of submarine rescue since the first edition of Submarine went to press, and this seems like a good place to cover them. The first is that the American DSRVs are rapidly coming to the end of their useful service lives and require replacement or upgrade. Also, the dedicated rescue ships that could operate the old McCann rescue chambers have been retired, meaning that the DSRVs delivered on the backs of submarines are now the only deep-water rescue system in the U.S. inventory. On the plus side, though, new rescue technologies are being designed and tested, and may be backfitted onto existing DSRVs.
The arrangement of periscopes, sensors, and communications masts on the conning tower/sail of USS Seawolf (SSN-21). RUBICON, INC., BY LAURA DENINNO One of the most promising of these is a new kind of mating collar, composed of angular slip rings that allow docking even if the downed boat is resting at a severe angle. Whether this new system will be retrofitted to the existing DSRVs as part of a comprehensive overhaul or to a completely new vehicle remains to be seen. For now, though, submarine rescue still remains an 'iffy' proposition at best.
Farther forward is the sail, which is, frankly, one of the slickest such structures ever built onto a U.S. submarine. Unlike traditional American nuclear subs, Seawolf has a curved faring blending the front of her sail into the hull to help reduce resistance and flow noise. It is just one of many little touches designed to keep the Seawolf-class boats the quietest ever to roam the world's oceans. As in previous American SSNs, the sail contains all of the sensor masts, as well as the control station for conning the boat on the surface. The mast-mounted sensors include:* Periscopes: As in previous U.S. submarine designs, the Seawolf is equipped with a pair of optical periscope masts. These include both Type 8 Mod 3 and Type 18 scopes, of the same variety as those described earlier on Miami.* Radar: To provide surface and some limited air search capabilities, a BPS-16 set is installed for operations in poor visibility and at night.* Radio Masts: A pair of AN/BRA-34 communications masts are provided to support the growing bandwidth requirements for littoral operations.* Electronic/Signals Collection Masts: To support intelligence collection and tactical situational awareness, Seawolf has an AN/BRD-7/BLD-1 mast with the collection heads for the WLQ-4 (V)1 and BLD-1D/F radar and signals receptions systems.* Trailing Antenna: To provide command cueing while submerged, the Seawolf has an OE-315 trailing wire antenna that can receive transmission from the Navy's Extremely Low Frequency (ELF) communications system.
All this, along with the improved processing and display technology of the BSY-2 combat system, makes Seawolf a truly revolutionary design-and just think, we've not even touched on the weapons load yet! That, too, is a major improvement over that of the older 688Is.
As we continue with our 'hull walk,' you'll probably notice a large hatch directly aft of the sail structure. This is the oddly shaped weapons shipping hatch and is used in the slow, monotonous process of loading torpedoes, weapons, and other stores inside the boat. One by one, each of the torpedoes (up to a maximum load of fifty) and other weapons must be brought down into the sub and laid in the torpedo room for storage in the event of combat. The weapons load of the Seawolf, twice that of the Flight I Los Angeles-class boats, was mandated by the desire to have enough warshots to sustain multiple engagements during prolonged wartime operations. To get these weapons off the boat quickly, Seawolf is equipped with eight 26.5-inch /673mm torpedo tubes, the biggest ever fitted to an American submarine. Utilizing a new air turbine pump system to expel the weapons more quietly than earlier water-ram methods, the new tubes are also capable of launching unmanned surveillance vehicles and even divers, should that be necessary. One thing the 688Is had that has been deleted from the Seawolf is the bank of Vertical Launch System (VLS) missile launchers in the bow. With her huge internal weapons stowage and eight torpedo tubes, the Seawolf was considered well enough armed to eliminate the VLS tubes.
As with every other element of submarine technology, ten years makes a big difference in weapons. Since the early 1990s, there have been significant changes and improvements to the weapons carried by the Seawolf- class boats. First off, all of the UGM-84 sub-Harpoon antiship missiles have now been withdrawn from service in the U.S. submarine fleet. This is mostly due to the fact that each Harpoon takes up space that might be used to hold a more frequently used torpedo or Tomahawk cruise missile, something that has made the sub-launched version of these formidable weapons go the way of the dodo bird.
