Type 21 Sonar Speed Findings?

Manock · 05-31-06, 11:19 PM

How do you obtain target speed using the Type 21 sonar?

The manual says this particular sonar can get both range, and speed but my fooling around with the controls only gives me range.

I just wallowed in and out of a convoy in heavy fog, and really could have used this feature.

Any help?

BigBadVuk · 05-31-06, 11:48 PM

Someone correct me if im wrong but i think that this feature is NOT implemented in game...Manual says it shud be but it is not

CybrSlydr · 05-31-06, 11:49 PM

Well, you can derive speed when given distance and time.

Speed = Distance/Time

Take one distance reading, mark off, oh.. 5 seconds. Take another. Subtract both to get the distance traveled. Take that distance traveled over the time and you have speed. (of course, you'll have speed in Meters/Second, so you'll have to convert Meters/second to knots - according to a quick Google search, knots meters per second 0.5148)

Now, unless you're stationary, you also have to factor in how much closer you got to the position as well to keep accurate.

Of course, the more readings you take, the more accurately you can plot their current speed.

Dunno the specifics (like if you have to be 90deg from the ship or if both will work, etc) - I was never very good at math.

CybrSlydr · 06-01-06, 08:13 AM

Wow. Nobody has posted yet to prove I'm incompetant at math! :rotfl::rotfl:

moselgott · 06-01-06, 09:38 AM

[quote=CybrSlydr]Well, you can derive speed when given distance and time.

Speed = Distance/Time

Take one distance reading, mark off, oh.. 5 seconds. Take another. Subtract both to get the distance traveled.
[\quote]

Actually this method only works if the angle on bow is 90° or 180°. Only in that case the distance to the enemy corresponds to the distance travelled by the enemy.

squigian · 06-01-06, 09:52 AM

For your method to work, you must make two points: one when you're exactly perpendicular to the ship's course, and one whenever you like. This gives a right-angled triangle. From there, you can caculate the distance travelled using Pythagoras' Theorem.

Exempli gratia

:

(You MUST remain still)

First point, you are 4km from the contact, bearing perpendicular to the course.
Second one, the contact is 5km away.

AB^2 + AC^2 = BC^2

4^2 + AC^2 = 5^2

16 + AC^2 = 25 [-16]

AC^2 = 9 [Square root]

AC = 3km

Now, we'll convert to knots later. Let's say it took 6 minutes ie. 0.1 hours.

=) S = d/t
S = 3/0.1
S = 30 km/h

Conversion to knots is km/h x 0.5399568 (0.5)

Therefore, the target is travelling at ~15 knots. Of course, the number's will never be this neat, so just round up; after all, nothing's perfect.

Manock · 06-01-06, 09:34 PM

Thanks for the responses but I was hoping for a sonic version of the attack periscope where you input the observations, and it does the work for you.

Despite this I lined up a lone merchant, and tried manual input with only sonar inputs, and missed twice, then I popped up the periscope, took visual sightings, and promptly fired two torpedoes in the wrong direction because I forgot to set the computer back to automatic.

Corrected, fired two more under automatic in which the first golden torp split the keel so the second torp wasnt needed.

Total torpedoes to sink one C3 - Six. How many needed - One.

When I get back to base, Im going to try and get laid quickly before my traitorous crew spreads this story around.

I think what we're looking for is a Law of Cosines solution but since I play this sim propped up in a hotel bed, I personally wont be cracking open the trig book on this.

Ducimus · 06-01-06, 09:51 PM

Nieblung (sp) sonar does not work as advertised in the game manual. It was probably supposed to gather speed information when they were designing the game, but they never implemented it. Right along with the top end radar unit for the XXI that was supposed to be able to work while snorkeling.

Amonng other features that they probably thought to put in, but for one reason or another didn't was:

-HF/DF (antenna is in)
- Radio mast
- Radar antenna's.

Why do i mention radar intennas? The matress style anntenna starting with, i think FuMo 30 is supposed to be on the port side of the conning tower, up top. The housing is already in place. Its that big regtangular gap. Instead they stuck it to the same attachment point as the Fumo29's diapoles. Maybe they ran out of time? I dunno. Regardless its a contstant annoyance in rough seas, as every time a big wave hits the antenna, the radar shuts off. If it were up top where its SUPPPOSED To be, it never would. (pet peeve)

Manock · 06-01-06, 10:28 PM

So thats whats going on. I get around that annoyance by high time compression. Whats turned on stays on above 256 or around there.

I heard that about radar and snorkeling also. It works to set it at 10m with just the top of the conning tower exposed but the actual detection of airplanes is so minimal as to offer nearly no time to submerge even as low in the water as you are.

Which brings up another issue about acting on red detection but thats for another post.

05-31-06, 11:19 PM	#1
Manock Bosun Join Date: Jul 2002 Posts: 68 Downloads: 0 Uploads: 0	Type 21 Sonar Speed Findings? How do you obtain target speed using the Type 21 sonar? The manual says this particular sonar can get both range, and speed but my fooling around with the controls only gives me range. I just wallowed in and out of a convoy in heavy fog, and really could have used this feature. Any help?

05-31-06, 11:48 PM	#2
BigBadVuk Ensign Join Date: Jan 2006 Location: Belgrade,Serbia Posts: 222 Downloads: 6 Uploads: 0	Someone correct me if im wrong but i think that this feature is NOT implemented in game...Manual says it shud be but it is not __________________ Any ship can submerge.. Only submarine can surface!

05-31-06, 11:49 PM	#3
CybrSlydr Lieutenant Join Date: Jul 2004 Location: Beverly, OH Posts: 263 Downloads: 13 Uploads: 0	Well, you can derive speed when given distance and time. Speed = Distance/Time Take one distance reading, mark off, oh.. 5 seconds. Take another. Subtract both to get the distance traveled. Take that distance traveled over the time and you have speed. (of course, you'll have speed in Meters/Second, so you'll have to convert Meters/second to knots - according to a quick Google search, knots meters per second 0.5148) Now, unless you're stationary, you also have to factor in how much closer you got to the position as well to keep accurate. Of course, the more readings you take, the more accurately you can plot their current speed. Dunno the specifics (like if you have to be 90deg from the ship or if both will work, etc) - I was never very good at math. Last edited by CybrSlydr; 05-31-06 at 11:59 PM.

06-01-06, 09:38 AM	#5
moselgott Watch Join Date: Apr 2006 Posts: 23 Downloads: 0 Uploads: 0	[quote=CybrSlydr]Well, you can derive speed when given distance and time. Speed = Distance/Time Take one distance reading, mark off, oh.. 5 seconds. Take another. Subtract both to get the distance traveled. [\quote] Actually this method only works if the angle on bow is 90° or 180°. Only in that case the distance to the enemy corresponds to the distance travelled by the enemy. __________________ "War does not determine who´s right, only who´s left" - Bertrand Russel

06-01-06, 09:52 AM	#6
squigian Helmsman Join Date: May 2006 Location: London, UK Posts: 107 Downloads: 0 Uploads: 0	For your method to work, you must make two points: one when you're exactly perpendicular to the ship's course, and one whenever you like. This gives a right-angled triangle. From there, you can caculate the distance travelled using Pythagoras' Theorem. Exempli gratia: (You MUST remain still) First point, you are 4km from the contact, bearing perpendicular to the course. Second one, the contact is 5km away. AB^2 + AC^2 = BC^2 4^2 + AC^2 = 5^2 16 + AC^2 = 25 [-16] AC^2 = 9 [Square root] AC = 3km Now, we'll convert to knots later. Let's say it took 6 minutes ie. 0.1 hours. =) S = d/t S = 3/0.1 S = 30 km/h Conversion to knots is km/h x 0.5399568 (0.5) Therefore, the target is travelling at ~15 knots. Of course, the number's will never be this neat, so just round up; after all, nothing's perfect.

06-01-06, 08:13 AM	#4
CybrSlydr Lieutenant Join Date: Jul 2004 Location: Beverly, OH Posts: 263 Downloads: 13 Uploads: 0	Wow. Nobody has posted yet to prove I'm incompetant at math! :rotfl::rotfl:

06-01-06, 09:34 PM	#7
Manock Bosun Join Date: Jul 2002 Posts: 68 Downloads: 0 Uploads: 0	Thanks For the Response But - Thanks for the responses but I was hoping for a sonic version of the attack periscope where you input the observations, and it does the work for you. Despite this I lined up a lone merchant, and tried manual input with only sonar inputs, and missed twice, then I popped up the periscope, took visual sightings, and promptly fired two torpedoes in the wrong direction because I forgot to set the computer back to automatic. Corrected, fired two more under automatic in which the first golden torp split the keel so the second torp wasnt needed. Total torpedoes to sink one C3 - Six. How many needed - One. When I get back to base, Im going to try and get laid quickly before my traitorous crew spreads this story around. I think what we're looking for is a Law of Cosines solution but since I play this sim propped up in a hotel bed, I personally wont be cracking open the trig book on this.

06-01-06, 09:51 PM	#8
Ducimus Rear Admiral Join Date: May 2005 Posts: 12,987 Downloads: 67 Uploads: 2	Nieblung (sp) sonar does not work as advertised in the game manual. It was probably supposed to gather speed information when they were designing the game, but they never implemented it. Right along with the top end radar unit for the XXI that was supposed to be able to work while snorkeling. Amonng other features that they probably thought to put in, but for one reason or another didn't was: -HF/DF (antenna is in) - Radio mast - Radar antenna's. Why do i mention radar intennas? The matress style anntenna starting with, i think FuMo 30 is supposed to be on the port side of the conning tower, up top. The housing is already in place. Its that big regtangular gap. Instead they stuck it to the same attachment point as the Fumo29's diapoles. Maybe they ran out of time? I dunno. Regardless its a contstant annoyance in rough seas, as every time a big wave hits the antenna, the radar shuts off. If it were up top where its SUPPPOSED To be, it never would. (pet peeve)

06-01-06, 10:28 PM	#9
Manock Bosun Join Date: Jul 2002 Posts: 68 Downloads: 0 Uploads: 0	So Thats What Happened So thats whats going on. I get around that annoyance by high time compression. Whats turned on stays on above 256 or around there. I heard that about radar and snorkeling also. It works to set it at 10m with just the top of the conning tower exposed but the actual detection of airplanes is so minimal as to offer nearly no time to submerge even as low in the water as you are. Which brings up another issue about acting on red detection but thats for another post.