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The World's First Supercavitating Boat?
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."
At least know one can blame you for not rtfa.
http://www.prnewswire.com/news-releases/juliet-marine-systems-inc-announces-the-first-super-cavitating-ship-ghost-127461283.html
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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/
This is a Mac, what you have there is an embarrassment to your fellow computer users.
Submission has one: http://www.xconomy.com/boston/2012/06/21/juliet-marines-ghost-ship-emerges-from-stealth-startup-gears-up-for-war/?single_page=true
Article has enough keywords to uniquely locate the original article
That's because
A sub is always a boat. Navies have always called them boats, that's why your submariner friend calls it that.
You might not like it, but "boat" is the correct term.
Lost at C:>. Found at C.
The Ghost shown on the Juliet Marine web site (http://julietmarine.com/) is a surface ship that doesn't look anything like two torpedoes. In fact, if anything, it looks similar to an original Start Trek series shuttle craft with bigger (and fold-able) wings. Also Ghost was announces in Aug 2011, so where's the news exactly?
Ouch. That article was so full of buzzwords and hype that my brain started cavitating.
Faster! Faster! Faster would be better!
This is not a submarine.
FTA: like a high-tech torpedo, except part of the craft is above water—
And the picture shows the entire boat is above water except the drive.
Sig Battery depleted. Reverting to safe mode.
The main compartment of the Ghost vessel, which houses the cockpit and controls, sits above the water in between two torpedo-shaped pontoons or “foils,” which are submerged and create all the buoyancy and propulsion for the craft.
Would be interesting to see it in the open ocean with the high waves. If the wave height is higher than the boat clearance it's similar to hitting the water surface at 100 mph. A nosedive at such a speed means the cockpit becomes a 12-seat grave.
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 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.
When you have nothing left to burn you must set yourself on fire
"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.
Is it just my observation, or are there way too many stupid people in the world?
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.)
My AC stalker: " I personally agree with your posts most of the time, but that won't keep me from modding you troll"
Ouch. That article was so full of buzzwords and hype that my brain started cavitating.
But did it *super*cavitate? Inquiring minds want to know! :)
Therefore, by the (faulty) logic you're using, you're just a cow with a keyboard - osu-neko (2604)
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.
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
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 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. 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 but it does expect its ships to self deploy. Sure the navy could use a cargo vessel to carry the new s
Also to say they can't be detected by sonar is wrong - they can't be detected by sonar from behind or directly in front, since the boat would be moving faster than the sonar waves straight on going forward (unless the boat also absorbs sonar, that is).
For your claim to be true, it would have to be moving around 3300 mph. Not likely. Cavitation generates a huge amount of noise. For a "supercavitating" torpedo you don't care because the target can't outrun it or often react fast enough to make evasive maneuvers.
It would also be nice if the article made the distinction between cavitating and injecting air at the bow. Air injection at the bow has some beneficial benefit for drag (not called friction in water) and acoustic (isolates hull noise from the water), but it also generates its own broadband noise.
In addition, the claim is made by the inventor that the US Navy has no defense plan in place WRT small boat swarms, so his is the only solution. Wrong.
I can attest that is a blatant falsehood, and that our Navy does indeed train for exactly that sort of warfare. I don't think it is revealing any sensitive info to point out the fact that a certain well known, very-fast-boat manufacturer has an ongoing contract with the Navy conducting offshore exercises using 40-50' "attack" boats powered by twin or triple 250-300hp outboard engines. I've hung out many times with the guys running those boats, and they do not operate in any sort of "blacked out" manner. They use public and privately-owned marine facilities, and conduct operations in broad daylight within areas used by recreational offshore fisherman, so I am sure that the inventor is aware of them as well. These boats can easily run in excess of 70mph, and while they may be very high-dollar craft in the consumer market, they cost less than $500K apiece.
The one advantage his invention has over these conventional hulled boats (other than raw speed) is that this is a wave piercing design, which as stated ITFA is better for the health of those aboard. That said, I seriously doubt it has anywhere near the maneuverability of more conventional offshore craft such as those I mention above. The turning radius would have to be *extremely* large with that cat hull configuration, and even moreso at super cavitation speeds. And how large a sea state can it run in? Keeping that pod above water and waves at 200mph (or even 1/4 that speed) would be absolutely critical. Water being non-compressible, one good impact would likely render that platform unusable. So - it's very fast, but can't turn/maneuver for shit, and will primarily be useful only in areas where seas will remain relatively calm.
The inventor speaks glowingly about his $20-million-dollar-per solution becoming a multi-billion dollar industry. To me, knowing what I know about water craft, it seems to me as if he is selling the US Navy a marine version of TSA body scanners. Another Federal boondoggle...
"...there are some things that can beat smartness and foresight. Awkwardness and stupidity can." ~ Mark Twain
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....
But I'm a pretty good troll.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
You are either confused or you didn't read TFA. This is a $10 million private sector development. Yes they are trying to interest the Navy/CG but were they really interested is would have been mentioned. If you want to beat on government spending go find a subject where the government is actually doing the spending.
Democracy is a sheep and two wolves deciding what to have for lunch. Freedom is a well armed sheep contesting the issue