Semi-sebmergible boat

North Korea's secret weapon????????????

Why do I want one?

http://www.specwarnet.com/asia/NKSF.htm
Semi-sebmergible boat: A fast, three-engined boat used for inserting small teams of commandos. WIth a top speed of around 50 kts, it will race at high speeds towards it's target and then submerge for the final approach.



http://www.strange-mecha.com/ship/M-Sub/N-Korea01.htm
Hi Speed Submergible Boat (North korea)

Length : 12.8m
Width : 2.9m
Draught : 0.62m
Displacement : 10t
Draught : 2.5m
Engine : Engine X 3
Max Speed :
74 - 93Km/h (On the water)
85Km/h (Under the water)
Submarge Limit : 3m
Crew : 6 - 8
Special Equipment :
GPS, Electric wave absorption paints, Schnorchel

The boat was sunk in December 1998 by the South Korean navy Destroyer.

 

85 Km/h submerged at 3m???

I don't think so.

 

I think you are right, that must be a typo..............thought I read that it can only go 3 or 5 knots underwater which would not be enough to fight the tide in some cases.

50 kts over water is not bad - kicking up a roostertail at speed is a dead giveaway with surface to surface radar though.

EDIT:
I found this....................

http://www.globalsecurity.org/military/world/dprk/navy.htm

 

With a 10T displacement at that length I doubt it can do the claimed speed.

 

It tends to go a little faster when people are shooting at you.

 

That is one weird looking hull form. What do the North Koreans know that we don't? Notice the inflection at around station 3-4? What's up with that? What about the extra thick gunwale there?

Looks like an aluminum hull with a FRP deck?

 

Interesting comments.......................it does look a lot like a tri-hull or is it trimaran?

Notice the STRAKES on the side of the hull?

Makes you wonder what the bottom looks like.

Here is a strake on a car:
http://www.mulsannescorner.com/newsmarch03.html

Riblets are used on aircraft wings:
http://aerodyn.org/Drag/riblets.html

Shark Fins....vortex generators used on the new Mitsu:
http://forums.pelicanparts.com/showthread.php?s=&threadid=196276&highlight=shark+fins

Lex Fence on the F-18 Hornet:
http://www.nas.nasa.gov/Main/Redirector/redirector.php?old_url=http://www.nas.nasa.gov/Pubs/TechSums/

...............and some more:
http://www.aerospaceweb.org/question/planes/q0176.shtml

Dimples:
http://www.aerospaceweb.org/question/aerodynamics/q0215.shtml

Have you heard of the Bionic Dolphin?
http://www.innespace.com/

I know North Korea has lots of mini subs - don't think they have something as cool as the Bionic Dolphin though.

NOTE: In the Riblets link there is a section on flexible sidewalls similar to Dolphin blubber giving in to water pressure at speed. The flexing makes it go faster, perhaps though vortex generation or bubble captivation, I don't recall exactly.

 

Awfully cool, but during WWII (I dunno if someone's already said this...) frogmen would use limpet mines and torpedo shaped minisubs. The Brits also had a submersable kayak.