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The Military Transportation Science Technology

The World's First Supercavitating Boat? 186

An anonymous reader writes "For decades, researchers have been trying to build boats, submarines, and torpedoes that make use of supercavitation — a bubble layer around the hull that drastically reduces friction and enables super-fast travel. Now a company in New Hampshire called Juliet Marine Systems has built and tested such a craft, and says it is the world's fastest underwater vehicle. The ship, called the 'Ghost,' looks like two supercavitating torpedoes with a command module on top, and can carry 18 people plus weapons and supplies. The company is in talks with the U.S. Navy to build a version of the ship that can guard the fleet against swarm attacks by small boats. The question is how well it really works, and whether it can be used reliably and effectively on the high seas."
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The World's First Supercavitating Boat?

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  • The summary contains a link that doesn't have an href attribute.

    • Re: (Score:2, Funny)

      by Anonymous Coward

      At least know one can blame you for not rtfa.

    • Re:Link, please? (Score:5, Informative)

      by cachimaster ( 127194 ) on Thursday June 21, 2012 @03:53PM (#40402967)

      Article has enough keywords to uniquely locate the original article [wired.com]

    • Just a test to see if you're really trying to RTFA.

    • I thought in the submariners' world cavitation was a bad thing? Reason: It makes a lot of noise. That's why they move around slowly at 10-15 knots, rather than full speed with the propeller producing noisy bubbles. (And also why the Russians kept trying to steal our propeller tech, because their propellers tended to cavitate, making them easy targets.)

      • Re:Link, please? (Score:5, Informative)

        by Carnildo ( 712617 ) on Thursday June 21, 2012 @05:11PM (#40403911) Homepage Journal

        There's a difference between cavitation and supercavitation. Supercavitation takes those noisy bubbles that are destroying your propeller and extends them to enclose the entire vessel. This reduces the amount of surface in contact with the water, which greatly reduces drag, and all of a sudden you're rocketing along at 200 miles per hour and don't particularly care if people hear you coming.

      • by amorsen ( 7485 )

        You don't really care if you can be heard by sonar if you're doing 100 knots submerged. Torpedoes can't hit you except by dumb luck straight on.

        Of course this thing is not completely submerged so you do have a chance against it with guns. Possibly also with a missile, but with no heat signature (it probably dumps waste heat in the water) and low radar signature you will have to get quite lucky.

        • Possibly also with a missile

          Capital ships can't evade anti-ship missiles if the missile is on target and survives the CIWS [wikipedia.org], so the missile doesn't need to be very manuverable.

          Something this small would be a very difficult target for current missiles, even with perfect detection.

      • by treeves ( 963993 )

        10-15 kts? No, more like 4 kts. "Four knots to nowhere", as we used to say.

    • Re: (Score:3, Insightful)

      by cachimaster ( 127194 )

      Great, another public relations company "news". No reporter was involved on this, 100% paid advertisment.
      This is journalism today. You want to be on the news, just pay for it. Even slashdot is part of the system now.
      BTW this work for universities too, that's why MIT makes the new every time they wire a microcontroller to a dishwasher.

      • by gstoddart ( 321705 ) on Thursday June 21, 2012 @04:29PM (#40403429) Homepage

        Great, another public relations company "news". No reporter was involved on this, 100% paid advertisment.

        Did you actually RTFA? They're citing people who are casting doubts on the claims, they're talking about people who refused to comment.

        So, I'd be more inclined to believe you read the first paragraph and have decided it's a press release.

        The presence of things like "I am dubious about the application of supercavitating propellers" tells me this wasn't simply word-smithed to provide only glowing praise.

        • I'm more dubious that they call it an "underwater vehicle". It's motors are underwater. People are above water.

          • I'm more dubious that they call it an "underwater vehicle". It's motors are underwater. People are above water.

            That's to distinguish this vehicle, which still has significant mass below the surface of the water when running at speed, from speedboats that run on a plane when at speed.

          • Because part of it travels under water, as opposed to hydroplaning boats that travel on the surface of the water.
            • How is it fundamentally different than a regular boat, whose engine is in the water and some of the boat?

        • GP probably wasn't referencing the article in the submission. GP probably was thinking of the link in the previous comment, which was in fact a PR puff piece.

      • by bws111 ( 1216812 )

        That 'prnewswire' link someone posted is just a press release, and is not the article referenced in the summary.

      • by jo_ham ( 604554 )

        How did this garbage parent comment get +5 insightful?

        I take it that your company routinely puts out press releases that call the product's value and science into question? That's why it's doing so well, right?

        Let me guess; you skimmed the first paragraph and then rushed to hit the reply button on /. to try and get high up on the page?

      • by Teun ( 17872 )
        Advertisements have their place.

        But why in the world when your only possible/ legal customer is the US Navy?

  • I've tried the link in IE, firefox, and crome and it doesn't appear to work? I searched around and found pictures and more info. http://deskarati.com/2012/01/19/worlds-first-super-cavitating-watercraft/ [deskarati.com]
  • So true it was underlined!

  • Is this a submarine or not? Wikipedia calls it a surface boat, while the linked article is unclear. Anybody have some solid info on this thing?
    • by Ken_g6 ( 775014 )

      It's clearly a surface boat. From TFA:

      It “flies” through the water more or less the way it was designed to—like a high-tech torpedo, except part of the craft is above water...

      • You can't change TFA after I post and then say "Hey look it's in TFA. Are you blind?". Morons.
      • This is like a supercavitating hydrofoil. This is not like a WiG (Wing in Ground) craft. Similar to a cement mixer full of bowling balls falling off a cliff, it is loud and fast (and I assume can be dangerous, too). It is not like a ham sandwich. It's not a big truck. It's not something you just dump something on.
  • The air force did GPS, then the stealth, then drones.

    Now it's the Navy's turn - nuclear, rail, speed and stealth.

    Frankly, the nuclear powered rail gun is probably going to be the biggest improvement in a long time. The navy will develop it for their new magnetic rail launch system for jets off a carrier, then move it to direct attack..

    • by srussia ( 884021 )

      Now it's the Navy's turn - nuclear, rail, speed and stealth.

      They should really hire some people who know Latin though. After the "velocitas eradico" railgun fiasco, I wouldn't be surprised if the motto for this thing is "cavitas pecuniae".

  • The fine article links to only one of the patent applications. There are actually two (with lots of figures):

    20120097086 FLEET PROTECTION ATTACK CRAFT AND UNDERWATER VEHICLES [freepatentsonline.com] (39 figures) and

    20110226173 FLEET PROTECTION ATTACK CRAFT (36 figures) [freepatentsonline.com]

  • by Lev13than ( 581686 ) on Thursday June 21, 2012 @04:19PM (#40403319) Homepage

    This type of boat is probably too limited in usefulness to be adopted by the navy. In terms of R&D capabilities it feels a lot like the experiments from the 1960s to develop militarized hydrofoils - the Canadian HMCS Bras d'Or [wikipedia.org] being one good example. Despite impressive stability and speeds in excess of 60 knots (70mph), the limited load capacity and range made the prototypes unsuitable for military use.

    The biggest hit, however, was the introduction of missiles. The difference between 20 and 30 knots isn't all that important when you're defending against a Sea Sparrow running at 500 mph. In WWII there were lots of destroyers running in excess of 35 knots. Now it's just the nuke-powered ACs that do top speeds, and everyone else is more worried about conserving fuel.

    That means the proposed boat is really just a replacement for patrol vessels or stealth assault craft, and it doesn't look like the advantages of the design outweigh the compromises in handling, noise, carrying capacity and cost.

    • by Hentes ( 2461350 )

      On the other hand, if they can modify this technology to be usable on submarines that would be a huge change.

    • It's limited in usefulness if you were looking to deploy them in the traditional sense of leaving port and not returning to land for months. However, you could put them on a carrier like we do aircraft, and launch them from there for regular patrols, assaults, and as a way to quickly gain superiority in the water in naval battles.

      You'd just need to retrofit some your smaller escort ships to each be able to launch one or two. Or build a whole new class of carriers for them, which while cool, probably isn't e

    • Its also not clear to me that it would fill a different niche than an ekranoplan (ground effect flying boat). These were developed by the Russians and worked, but as far as I know were not found to be militarily useful.

      Same for comparisons with helicopters or slow ground attack aircraft.

  • by Overzeetop ( 214511 ) on Thursday June 21, 2012 @04:26PM (#40403387) Journal

    "Sancoff said that what’s in the patent filing isn’t quite how it works."

    That should be forwarded to the examiner and the book closed.

    • "Sancoff said that what’s in the patent filing isn’t quite how it works."

      That should be forwarded to the examiner and the book closed.

      I think the government may intervene on behalf of Juliet in that case. There are a lot of foreign governments who would love an exact description about how this works.

    • He's not saying the patented method doesn't work; he's saying the boat doesn't use the method they patented. Nothing wrong with that.

  • This article makes no sense.

    "The angle of the struts that connect the foils to the command module is adjustable—so the craft can ride high in choppy seas and at high speeds (so waves don’t hit the middle part), and low in calm water and at lower speeds.

    “We’re basically riding on two supercavitating torpedoes. And we’ve put a boat on top of it,” Sancoff says."

    Ok, so it's a hydrofoil...

    "The propellers are powered by a modified gas turbine—a
    • wait... what? It's a surface vehicle that's faster than any previous underwater vehicle?

      Name one vehicle that travels 100 knots with a significant part of it under water. All hydroplaning boats don't count as they travel on the surface of the water.

      Ok, it's powered by JET ENGINES but you can't hear it from 50 feet away? um... yea...

      I'd believe it. The engines are under water. You could probably hear it from kilometers away under water though...

  • It sounds like they use an envelope of bubbles to encase the nacelles in air to reduce the friction between the nacelles and the water. If it works for increasing the speed through water, maybe the same methodology can be applied to increase speed of travel through air.... Surround the craft with a vacuum to reduce air friction. Maybe call it superturbulence.
  • by jklovanc ( 1603149 ) on Thursday June 21, 2012 @05:51PM (#40404415)

    I did a little research on some of the claims in the article;
    From the article;

    It was there, in 2000, that he first got inspiration for Juliet Marine and the Ghost ship. Sancoff was sitting in a conference room when he heard the U.S.S. Cole had been attacked off the coast of Yemen by a small boat loaded with explosives.

    The USS Cole was attacked while in port tied up along a jetty refueling. All of it's radars and weapons systems were down and the ship was defenseless. An innocent looking small boat moved up to the hull and exploded. That was a port security failure and nothing to do with the weapons capability of the Cole. Referring to that incident in the context of massed small boat attacks is bunk.

    From the article;

    I looked at the Fleet Battle Experiment Juliet Final Summary Report [dtic.mil] and nowhere did it mention a high number of losses due to small boat attacks. Even if the statement is true, Juliet took place 9 years ago and I bet there has been a lot of learning and experimentation since then.

    Now lets look at the technology. In general it works by a propeller spinning so fast it creates enough low pressure behind the propeller to boil the water and create water vapour which reduces drag along the rest of the sponson. Here are a few issues;
    1. The way a propeller works is that it pulls in water that is approaching the propeller at one velocity and ejects it at a higher velocity from the back of the propeller. This creates a low pressure area behind the propeller. If the velocity differential is enough the low pressure is enough to lower the boiling point of the water and cause it to turn to water vapour. This large velocity differential in generally obtained when a vessel is accelerating or decelerating. There is a point at which the velocity of the ship approaches the maximum velocity of the water ejected from the propeller. This will decrease the low pressure to a point at which cavitation will stop.
    2. Propeller cavitation is very hard equipment. I know the chief engineer on a ferry and he cringes every time he feels cavitation. He knows that they just spent thousands of dollars on propellers, bearings and shafts just because some sod at the helm didn't slow down at the right time. Anyone who has traveled on a ferry has experienced cavitation. It usually occurs during docking and the whole ship shakes. When propellers cavitate is is not a smooth process. Bubbles of water form on the back of the propeller, detach and then water slams back in. This causes damage to the propeller [wikipedia.org]. How long can the new ship go before expensive overhauls? Drag racers are rebuilt after every run, is it really feasible to use that same model on a warship? It may work on torpedoes but they are one use weapons.

    The article makes several references like "to reach very high speeds at relatively low fuel cost." The question is relative to what? A conventional boat attempting 100 knots or a 30kt destroyer. If comparing with a high speed boat they may be less but pound for pound it is a lot more than a DDG. If the range of one of these vessels is only a few hundred mile it will be difficult to get in theater and spend much of it's time sitting next to a ship refueling.

    I love the following statement;

    Its fuel efficiency means it has greater range and can run longer missions than conventional boats and helicopters.

    There is always an issue when using relative terms; in general they are meaningless.Technically speaking a 1% increase in range is longer. What is the actual difference in range and is it enough to self deploy? The military does not expect a helicopter to self deploy, hence the need for helicopter carriers [wikipedia.org] but it does expect its ships to self deploy. Sure the navy could use a cargo vessel to carry the new s

  • by mbstone ( 457308 ) on Friday June 22, 2012 @04:10AM (#40408861)

    Supercavitationistic Bubblicious Warships,
    The enemy don't have this stuff, It's only found on our ships,
    Faster than the Russian navy, Chinese or Qatar ships,
    Supercavitationistic Bubblicious Warships.

    Um diddle diddle diddle um diddle aye,

    It goes a hundred knots per hour and uses little fuel,
    Looks just like the Bird of Prey from Star Trek #2,
    The DoD they can't believe the small size of the bill,
    The sucker was developed for just $150 mil....

God helps them that themselves. -- Benjamin Franklin, "Poor Richard's Almanac"