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Belesarius

General Naval Warfare News/Technology thread.

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GAO Report on readiness issues in the USN.

 

https://news.usni.org/2017/09/07/gao-written-testimony-congress-navy-readiness-problems-related-uss-john-s-mccain-uss-fitzgerald-collisions

 

37% of certifications, including basic seamanship for ships based in Japan have expired. WTF USN?

 

 

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1 hour ago, Collimatrix said:

I always assumed that the Shkval worked due to the shape of the nosecone and by gas injection forwards from it.

 

This approach would use a heated or polymer-coated nosecone which directly interfaces with the water. Which could be technically easier or harder (or give better or worse results), but is certainly different from whatever Shkval is using.

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42 minutes ago, Collimatrix said:

That is also my understanding of shkval.  Either way; you're reducing hydrodynamic drag via cavitation.

Yup.

It seems like there might be a few ways to do it though - simply coating the torpedo in this shit might be a bit easier then stuffing a gas generator in the nose.

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Rods from god get into the km/s range - I think any reasonable material at those speeds would be full on hydrodynamic penetration even in water, and not achieve very much below a couple dozen meters

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8 hours ago, Belesarius said:

http://www.macleans.ca/opinion/for-smarter-shipbuilding-canada-should-look-to-denmark/amp/

 

Some interesting thoughts on shipbuilding in this article. @Collimatrix, I'd like your thoughts.

 

 

Quote

However, there is one exception to all of this. Denmark is able to deliver a large and capable warship for very reasonable cost. Their Iver Huitfeldt-class frigates have been proposed for Canada’s CSC project. At about US$350 million for a large 6,650-tonne ship, they are very economical...

 

... Rather than building 15 ships uniformly with high capabilities, the Danes build only the number of modules needed and change the ship accordingly. This results in major savings.

 

If you don't put a radar, or point defense missile system, or sonar on your ship, then you get a very cheap ship. That vessel is comparable in cost to the british type 31e design, which is likely to also lack most parts needed for a credible modern warship

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15 hours ago, Belesarius said:

http://www.macleans.ca/opinion/for-smarter-shipbuilding-canada-should-look-to-denmark/amp/

 

Some interesting thoughts on shipbuilding in this article. @Collimatrix, I'd like your thoughts.

 

 

It's an interesting idea, but there appear to be some basic logical discrepancies in this article.  Like this statement:

 

Quote

By saving on cost, the Danes build their frigates bigger than most. The extra space is used to duplicate a wide variety of shipboard systems in order to achieve greater reliability through redundancy. It also provides growth margins for easy and economical upgrading.

 

OK, that sounds good.  These Danish ships sacrifice a bit of efficiency or something and end up with larger displacement.  But then I did something I call the "is the sky really blue?" check.  You see, according to Wikipedia (yes, I know), the Iver Huitfeldt doesn't displace significantly more than the Type 26.  It's actually a little smaller.  It's also got less displacement than the Hobart class frigates too.  So, maybe the Iver Huitfeldt is a bigger frigate than some other frigate yardstick that I'm not aware of (I don't know that much about frigates), but compared to the other two classes of frigate mentioned in the article, these Danish frigates are smaller, which runs directly contrary to the author's explanation of how they're supposed to be better value!

 

Here's another thing that raises some alarms for me:

 

Quote

Larger ships are also more fuel-efficient.

 

I can buy that larger ships are more fuel-efficient pound for pound.  Hydrodynamic drag scales with frontal area, which is a square function of linear dimensions.  Mass scales with volume (for a fixed density), which is a cubic function of linear dimensions.  So the mass of a ship will increase faster than its fuel consumption if you scale it up.  But the fuel consumption is still going up, just not as fast as the mass.  Is this a simplification in order to present this to a lay audience, or is this an attempt to pull a fast one on the audience, or does the author just not understand the physics?

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https://breakingdefense.com/2017/10/every-ship-a-minesweeper-navy-looks-beyond-lcs/?_ga=2.74559953.217511175.1509364597-381149324.1509364597

 

Navy looking at the Distributed Lethality concept for mine hunting, piggybacking off the work done for the LCS module and tossing that all over the fleet.

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5 hours ago, Belesarius said:

 

Quote

 

Mitch McGuffie, a former U.S. surface warfare officer who served in an exchange with the U.K. Royal Navy for two years as a bridge officer, said that other navies place a higher value on navigation and ship handling than Americans.

“I was the go-to office of the deck on my first tour, and I thought I knew a lot of stuff. And then I went to the Royal Navy and I went through their navigator school, and it was the hardest class that I have ever gone through, with a 50-percent attrition rate,” he said.

British sailors specialize in a specific discipline at sea, unlike the U.S. surface warfare officers that are generalists. As a result, narrow specialties like navigation or bridge watches maybe given short shrift.

“People squeak through the system. They may be great officers and they may great engineers, but they might not have had a lot of time handling ships in busy waterways,” McGuffie told USNI News in an interview.
“We have guys that are commanding ships right now that have 400, 500 hours of bridge watchkeeping time in their career.”

In contrast, as the bridge officer on a Royal Navy frigate for a six-month deployment, McGuffie stood watch for more than 2,000 hours – all of them logged.

 

Huh, that's 11 hours every single day. RN must go hard in specialisation.

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