If someone comes from Korea and knows something more please post a link (and maybe a … short translation!)

—
“Yes, noise does not travel as fast underwater as on the surface, and even less so deep underwater.”

you are wrong

the deeper the water level is, the faster sound travels
—-
exactly. In the water the noise ‘moves’ faster as the density of the water is higher than the air.

- - -

Someguy,
#20 is correct about the speed of sound in water; travels ~8x faster in water than air. Any diver can tell you this.

“Yes, noise does not travel as fast underwater as on the surface, and even less so deep underwater.”

you are wrong

the deeper the water level is, the faster sound travels

#11 is saying that the sub may produce lower noise at deeper levels because he has asserted that the probable cause of the noise is cavitation.

at deeper levels, pressure is higher
higher pressure -> less probability of cavitation

and helping out Hyundai?

why did one of the Hyundai sons commit suicide, by jumping out of the building?

The problems that the South have appear to be very similar to the problems the Greeks had with the Type 214–the sub would roll excessively on the surface, propellers are noisy, etc. (http://www.strategypage.com/htmw/htsub/articles/20061211.aspx). Ironically, the Germans don’t appear to have the same problem with their Type 212s (the 214 is the export version of the 212). I seem to recall that the Greek and possibly the Korean versions had some design modifications that could have been the source of some of the problems.

This does not seem to be an issue with this being Hyundai’s first foray into submarine construction, although that is a good place to look first. Germany built Greece’s first Type 214 and it had all the problems that are arising now with the Korean one. This may be more of an issue with a new submarine design more than anything. I haven’t heard if Greece managed to eliminate or reduce some of the problems in subsequent submarines.

Designs get modified, though, as problems are identified. The first of anything as complex as a warship or submarine usually has a number of problems that get fixed in the next hull.

Actually the selection was done during the Kim Dae-jung administration. As you commented, there was a bit of controversy when HHI was selected to build the subs, considering that DSME was Korea’s “submarine house” and HHI at that time had no experience in building subs.

Three years after the selection, the BAI reported that there were “irregularities” in the evaluation process that resulted in the selection of HHI.

http://news.naver.com/main/rea.....0000201491

That wasn’t the only unusual selection process for defence equipment during the DJ administration. Remember the FX project? During the first round evaluation the Rafale came out on top, but after a second round evaluation that considered “political factors”, the F-15K was selected as Korea’s next fighter.

#13 Jing, the excessive shaft vibration resulting from cavitation would also cause the mechanical seal failure and therefore water leakage.

There was also some speculation about the design intentionally being not as good as it could be.

Also, “Jing”, please don’t take my comment above as being anything less than a friendly rejoinder; I did not mean to be nasty to you so I’m sorry if it read that way.