>From skunk-works-owner@ecn.purdue.edu Sun May 9 01:21:37 1993 Received: by fernwood.mpk.ca.us; id AA02522; Sat, 8 May 93 23:28:53 -0700 Received: by harbor.ecn.purdue.edu (5.65/1.32jrs) id AA06442; Sun, 9 May 93 00:32:08 -0500 Received: from orchestra.ecn.purdue.edu by harbor.ecn.purdue.edu (5.65/1.32jrs) id AA06435; Sun, 9 May 93 00:31:58 -0500 Received: from mail.swip.net by orchestra.ecn.purdue.edu (5.65/1.32jrs) id AA26597; Sun, 9 May 93 00:31:54 -0500 Received: from butler.icl.se ([140.150.93.12]) by mail.swip.net (5.65c8-/1.2) id AA08676; Sun, 9 May 1993 07:31:50 +0200 Received: from icl.se (sw2001.ki.icl.se) by icl.se (4.1/tomku_910926) id AA23907; Sun, 9 May 93 07:31:48 +0200 Received: by icl.se (4.1/SMI-4.1) id AA27823; Sun, 9 May 93 07:32:05 +0200 Message-Id: <9305090532.AA27823@icl.se> Subject: HMS Smyge To: skunk-works@orchestra.ecn.purdue.edu (Skunk Works-L) Date: Sun, 9 May 93 7:32:05 MET DST From: urf@ki.icl.se (Urban Fredriksson) Organization: None. I speak only for myself. X-Alt.Reply-Address: n.g.u.fredriksson@swe2001.wins.icl.co.uk X-Mailer: ELM [version 2.3 PL11] Sender: skunk-works-owner@ecn.purdue.edu Precedence: bulk Status: RO Now I too have seen pictures of Sea Shadow. To me, it doesn't seem like a very tactical vessel, not that I think it was intended as such. But the difference to the Swedish HMS Smyge (which of course was built 5 years later), which was built specifically to gain experiences for the building of combat vessels seems great to me. What could a Sea Shadow class vessel be used for, supposing it was a proof of concept ship for something to be built? Only a few roles comes to my mind: Covert insertion/extraction of troops, minelaying (where it's real useful not having the enemy knowing that you've been there) and mine hunting. Some of you may be curious on Smyge, so here I include an old article of mine. I think the correct terminology is "air cushion catamaran", "side-keel hovercraft" is a literal translation from Swedish, but I didn't know better then. - begin old article - The Swedish stealth ship HMS Smyge was first shown publicly in 1991. It will be used to evaluate signature reduction, new weapon systems and handling qualities (for example there is no deck to stand on). It is not a prototype for our next generation combat vessels, for one thing it is too small, and the weapons fit is not representative for a ship this size, but it has a little of everything for evaluation purposes. Configuration is a side-keel hovercraft, mostly manufactured of kevlar and glassfibre. It is designed to reduce radar, IR and noise signatures. All structures consist of angled flat surfaces and all in- and outlets are screened, the engines' exhausts are cooled and the use of water jets makes for a small noise signature. As only very little of the hull projects into the water (more than 80% of the ship is supported by the air cushion), it makes for a small pressure signature (there are Norwegian mine hunters with the same configuration). This also makes it relatively insensitive to underwater explosions. It has conformal and retractible antennas, including the elevating radar mast. Displacement: 140 tons Length: 30 m (27 m waterline) Width: 11 m, Draft 1.9 m at rest; 0.7 on the air cushion. Speed: More than 40 kt Crew: 14 (6 officers and 8 conscripts) Propulsion: 2 2040 kW diesels powering water jets Lift: 2 460 kW diesels Armament: 40 mm gun. The barrel can be depressed into the hull and covered by a hatch. RBS 15 anti-ship missiles, torpedoes and mines, all launchers covered by hatches. General arrangement: l l ____n___/###\ /####\ / \ / ____ \ | / || || ~~|____________/~~~~\|~~~~|/~~ The mast is there to comply with civilian regulations regarding lights etc. It also camouflages the stealthyness so that all other trials can be performed in view of the public. It is easily removed for stealth trials. - end old article - HMS Smyge isn't black, but painted in the normal gray/gray/gray/green splinter camouflage of our combat vessels. -- Urban Fredriksson urf@icl.se From weber@jedi.ssd.lmsc.lockheed.com (Weber) Subject: Stealth Ship Date: Mon, 12 Apr 93 18:20:29 GMT >From Aerospace Daily newswire: `SEA SHADOW,' a stealthy ship designed by Lockheed for the Navy and ARPA to demonstrate advanced ship technologies, is by the service. Navy unveils stealthy 'Sea Shadow' technology demonstrator ship The existence of an all black, Lockheed-built floating technology testbed designed to demonstrate ship stealth, among other things, was announced by the Navy Friday in anticipation of first-ever daytime trials over the weekend. The ship, called the "Sea Shadow," was built by Lockheed Missiles and Space Co. between 1983 and 1985 for about $50 million, as part of a broader program worth $195 million "over ten years," a Navy spokeswoman said. Funding came from the Navy and the Defense Advanced Research Projects Agency (DARPA). The service stressed that the vessel is "not a prototype for a `stealth ship,'" but "radar cross section was considered in the design." No further examples will be built. The vessel was a pathfinder for technologies now incorporated on the DDG-51 Arleigh Burke class destroyer, and its Small Waterplane Area Twin Hull (SWATH) technology "has been incorporated into the TAGOS-19" surveillance craft, the Navy said. Besides stealth, the Sea Shadow was designed to test new technologies in ship control, structures, "automation for reduced manning" and seakeeping. It is 160 feet long, 70 feet wide and has a draft of 14 feet, displacing 560 tons. The ship is powered by a twin screw diesel electric drive and can make 13 knots, providing "limited mobility," the Navy said. Owned by the Navy, the vessel is operated by Lockheed personnel. Lockheed built the vessel inside the Hughes Mining Barge (HMB) at Redwood City, Calif., where it was stored during during the daytime while testing was underway, and where it was mothballed from 1986 until late last year. The ship was painted black to hide it during night tests. Photos and drawings of the vessel were still classified Friday afternoon, pending an unveiling Sunday. But a Navy official, describing it, said the "sloped sides of the Sea Shadow are an extension of the angled struts," the design of which was "driven by signature, hydrodynamic and structural considerations." The ship was to have begun about three weeks of sea trials on Sunday, specifically to test structures and performance in heavy sea- states. The Sea Shadow was in storage since 1986, primarily because the Navy lacked funds to continue testing, the spokeswoman reported. Funding has since been found to "complete" the initially-planned series of tests. The ship was unveiled this weekend to allow it to "take advantage of limited testing range availability," during daytime. The announcement was made because its open transit of coastal areas would have drawn a flurry of inquiries about "its alien shape," a Navy official said. kevin