Make a Knuckle?

speed150mph · 04-06-14, 12:43 AM

So I read a lot of books by a lot of authors, and naval warfare is my favorite type of thriller. But this confuses me and I haven't found any definition for the phrase. I've heard it a lot in Joe Buff's "Jeffery Fuller" series, I've heard it in Jeff Edward's "USS Towers" series, and today I heard it in Tom Clancy's "Red Storm Rising". The isolated use in one book would right it off as a one time term made by the author, but we have 3 different authors here, all former navy guys.

so maybe I'm just clueless but I don't know what it means to "make a knuckle" besides the fact that its a torpedo evasion tactic. can anyone tell me the details of the maneuver?

Platapus · 04-06-14, 06:20 AM

If you turn sharply at a specific speed, you can create a disturbance..not in the force, but a disturbance in the underwater wake caused by the submarine. This swirling of the water will reflect active sonar.

In effect, you are creating a sound reflecting object (hunk of swirling water) behind you while you are scooting off in another direction. It is possible that this swirling (called a knuckle) can confuse an actively guided torpedo if you can get your submarine out of the cone of sonar detection of the torpedo.

I am not really sure how effective it is against today's torpedoes.

Jimbuna · 04-06-14, 08:13 AM

^

A knuckle is a defensive technique used by a submarine under attack. A submarine makes a knuckle by a sudden, sharp movement back and forth of the rudder. This leaves an especially tubulent spot in the water behind the submarine, and then the sub continues moving away. Because of how sound waves are bent and reflected in water, this "knuckle" can confuse an inbound enemy torpedo's target-homing sonar, and sometimes even fool the torpedo into thinking the knuckle is the actual submarine's hull. The result is thus hopefully that the torpedo (or the enemy weapons techs controlling the torpedo thru its guidance wire) will lose contact on the submarine, or else the torpedo will actually detonate against the knuckle, with little or no harm to the escaping sub itself. Knuckles can also be used to confuse/defeat active sonar being used by surface ships, sonobuoys, ASW helicopters with dipping sonars, etc.

speed150mph · 04-06-14, 12:19 PM

So in other words, making a knuckle is sorta the submarines version of cracking the whip. I'll have to try it next time I play dangerous waters, see if it works in the game.

thank you

04-06-14, 12:43 AM	#1
speed150mph Electrician's Mate Join Date: Feb 2013 Location: Alberta, Canada Posts: 132 Downloads: 35 Uploads: 0	Make a Knuckle? So I read a lot of books by a lot of authors, and naval warfare is my favorite type of thriller. But this confuses me and I haven't found any definition for the phrase. I've heard it a lot in Joe Buff's "Jeffery Fuller" series, I've heard it in Jeff Edward's "USS Towers" series, and today I heard it in Tom Clancy's "Red Storm Rising". The isolated use in one book would right it off as a one time term made by the author, but we have 3 different authors here, all former navy guys. so maybe I'm just clueless but I don't know what it means to "make a knuckle" besides the fact that its a torpedo evasion tactic. can anyone tell me the details of the maneuver?

04-06-14, 06:20 AM	#2
Platapus Fleet Admiral Join Date: Oct 2006 Posts: 18,960 Downloads: 63 Uploads: 0	If you turn sharply at a specific speed, you can create a disturbance..not in the force, but a disturbance in the underwater wake caused by the submarine. This swirling of the water will reflect active sonar. In effect, you are creating a sound reflecting object (hunk of swirling water) behind you while you are scooting off in another direction. It is possible that this swirling (called a knuckle) can confuse an actively guided torpedo if you can get your submarine out of the cone of sonar detection of the torpedo. I am not really sure how effective it is against today's torpedoes. __________________ abusus non tollit usum - A right should NOT be withheld from people on the basis that some tend to abuse that right.

04-06-14, 08:13 AM	#3
Jimbuna Chief of the Boat Join Date: Feb 2006 Location: 250 metres below the surface Posts: 181,284 Downloads: 63 Uploads: 13	^ A knuckle is a defensive technique used by a submarine under attack. A submarine makes a knuckle by a sudden, sharp movement back and forth of the rudder. This leaves an especially tubulent spot in the water behind the submarine, and then the sub continues moving away. Because of how sound waves are bent and reflected in water, this "knuckle" can confuse an inbound enemy torpedo's target-homing sonar, and sometimes even fool the torpedo into thinking the knuckle is the actual submarine's hull. The result is thus hopefully that the torpedo (or the enemy weapons techs controlling the torpedo thru its guidance wire) will lose contact on the submarine, or else the torpedo will actually detonate against the knuckle, with little or no harm to the escaping sub itself. Knuckles can also be used to confuse/defeat active sonar being used by surface ships, sonobuoys, ASW helicopters with dipping sonars, etc. __________________ Wise men speak because they have something to say; Fools because they have to say something. Oh my God, not again!! GWX3.0 Download Page - Donation/instant access to GWX (Help SubSim)

04-06-14, 12:19 PM	#4
speed150mph Electrician's Mate Join Date: Feb 2013 Location: Alberta, Canada Posts: 132 Downloads: 35 Uploads: 0	So in other words, making a knuckle is sorta the submarines version of cracking the whip. I'll have to try it next time I play dangerous waters, see if it works in the game. thank you