Virtual Earth image reveals Trident sub's secret propeller

Virtual Earth image reveals Trident sub's secret propeller

seattletimes.nwsource.com

This month, a photograph appeared on the Internet of the propeller on an Ohio-class ballistic missile submarine at Trident Submarine Base in Bangor. A key to the submarine's ability to deploy and remain undetected, propeller designs have been kept under wraps for years, literally. When out of the water, the propellers typically are draped with tarps. Several Navy watchers said the now-widespread propeller photo marks a first. "It's the first time I've seen that in the open source".

(visit the link for the full news article)


Related News Links:
www.monstermaritime.com

I'm not surprised more photos like this haven't showed up on the net. With all the sattelites in the sky watching our every move, one would think the millitary would be just as aware of this fact. What even surprises me more is that the Pentacon has hasn't requested to eliminate the the picture yet.

seattletimes.nwsource.com
(visit the link for the full news article)

Here is the picture




[edit on 1-9-2007 by highfreq]

[edit on 1-9-2007 by highfreq]

Picture doesn't work.

Just letting you know.

thats one crazy propeller. i wish i knew more about hydrodynamics and how that propeller actually affects water turbulence. think i can get one for my boat?

It worked for me. Interesting prop on that beast. There's still a lot about it that you can't tell, but I'm surprised they are letting this one stay out there.

reply to post by lightworker12


The link I believe only works if you have Internet Explore, since it came from MSN Live search.

worked fine for me in firefox and opera.

It works just fine with Firefox. I'm looking at it right now in another Firefox window.

This is the prop that's supposed to reduce cavitation and therefore make the sub harder to detect, if I remember correctly - it certainly looks complex, I jus wish I could zoom in a bit more.
Good pic

reply to post by lightworker12


M$ Virtual Earth is required to view the image. It is a free download.

It makes the Ohio boats some of the quietest ever built. As of the last I heard, there was only one ever tracked and that was due to a mechanical issue the boat suffered. The Seawolf and Virginia are quieter, but they use propulsor technology, not a screw like the Ohio does.

I can see why they're so quiet though. Curving the blades like that makes a big difference. They did that with the tip of the rotor blade on the UH-60 and it cut the noise down a lot. It actually slows the blade down somewhat, while giving the same amount of power output. By slowing it, it quiets it down, and makes it easier to move through the air (or in this case water). The same principle should apply with this prop as with the rotor blades.

[edit on 9/1/2007 by Zaphod58]

Looks almost scythe looking propeller. Interesting design.

Good deal.

I'm no expert on analyzing areial photography, so I ask what details in this photo could be classified as top secret other than the design. I would think that the pitch and dimensions would be more crucial than anything. But then again I'm no expert.

A submarine propeller itself is classified. Once you have the basic design it's actually quite easy to develop a similar blade. The Japanese gave the Soviets the design for a new propeller for the Akula submarines, and it was quite a shock when they were suddenly sneaking up on our Los Angeles class attack subs without them having any clue the Akula was there until it was too late.

things looks to be about 20ft diameter or so.
huge, love the bent blade design i wonder what material is used, doesn't look like bronze maybe stainless?? tose huge props like that cant sit still very long or they collapse under their own weight they have to constantly be ticking in a slow rotation.

[edit on 1-9-2007 by infiltr8u]

Can someone please screenshot it or something I don't feel like downloading a program just to see this.

Originally posted by Kacen
Can someone please screenshot it or something I don't feel like downloading a program just to see this.

Here you go...

Originally posted by Zaphod58
The Japanese gave the Soviets the design for a new propeller for the Akula submarines, and it was quite a shock when they were suddenly sneaking up on our Los Angeles class attack subs without them having any clue the Akula was there until it was too late.

Actually it wasn't the design, it was the equipment to mill the propellers.

The machines are used to make complex propellers for Soviet submarines, viewed by Pentagon officials as a major setback for American military forces. The new equipment has apparently made it far easier for Soviet subs to elude detection in recent months. Noise from propellers is a key factor in tracking undersea movements of the Soviet Navy.

query.nytimes.com...

On a side note, I swore that I would never work for Toshiba when I got out of the Navy... Nine months after I was out and working for a really cool and progressive American company... Toshiba bought them... I didn't stick around long.

That really chapped my...

Here's another interesting perspective:

This in turn indicates that rafting and other, more advanced quieting techniques first adopted by Thresher in the United States were probably adopted by the Soviets only with Victor III. It also demonstrates the significance of the Toshiba, nine axis milling machinery obtained by the Soviet Union which gave them the ability to make the kind of skew back propellers that reduce blade rate tonals.(84) This technology, combined on Akula with the quieting technologies already demonstrated on Victor III, gave the Soviets by the mid 1980s a nuclear submarine that could elude SOSUS and frustrate efforts by tactical ASW platforms using passive sonar to establish and maintain contact with it.(85) At long ranges its narrow band, low frequency tonals had been reduced below the source level of its continuous broadband signature, and the source level of that broadband signature was close or equal to that of American Sturgeons and early 688s.(86) Absent a strong narrowband tonal structure, and with low broadband source levels, passive acoustic detection, classification, and localization of submarines becomes quite difficult at long range, and counter-detection becomes more likely at shorter ranges.

www.navy.mil...

[edit on 1/9/2007 by Mirthful Me]

This is a pretty fun page to read. It talks about the adventures of trying to get a picture or drawing of a submarine prop for a museum.

www.americanhistory.si.edu...

As for what they're made of, that's classified. They'll admit to what the OUTSIDE casing of a Sturgeon class submarine propeller is, but that's only because it's been declassified since they're no longer in service and a very old design, but they won't say anything about the inside as that's still classified.

For more modern propellers it's some kind of nickel-aluminum-bronze alloy. At one point they were working on bringing production time for a screw down to four months from 12 months. They start with a 20 chunk of metal and cut it down and then smooth and polish it. To give you an idea of the size of a screw, the finished product has been machined down to 41 tons.

[edit on 9/1/2007 by Zaphod58]

reply to post by Mirthful Me


I had heard it both ways. One source said the entire design, one said the machines to mill it.