Screw Revolutions to Determine Ship's Speed.
 

I heard about SONAR in World War II that tracks the speed of a ship by counting the number of screw revolutions on a ship by simply listening to them by sonar. On SONAR, the sonar operator uses it to judge the speed of the ship that he is target.

Now,
I'm wondering if we could simply have a way for the sonar operator to send the speed to the TDC as well as the Range and Bearing. It would be so cool to have a send speed to the TDC icon for Silent Hunter IV so that players don't have to guess what the speed of an enemy ship is. Are there other ways to measure speed, other than by visual observation? Visual observation seems to take a long time in combat, especially when they're shooting at you.

Why can't there be a sonar that gives you the speed of an enemy ship to save time? :rock:
:up:
It would save time. Shouldn't there be a sonar speed that gives the speed of a target? It saves me a lot of time tracking a ship. Can it be done in Silent Hunter IV?


http://www.maritime.org/fleetsub/sonar/chap4.htm

There is a prop count detector for the sonar unit. As you can see. This would be cool to have in SIlent Hunter IV, I think because I get the speed of a ship in less time that the current
game allows.


History

All nautical instruments designed to measure the speed of a ship through water are known as logs. [1] This nomenclature dates back to days of sail when sailors tossed a log attached to rope knotted at regular intervals off the stern of a ship. The sailors would count the number of knots that passed through their hands in a given period of time. Today sailors still use the unit of knots to express a ship's speed. The speed of the ship was needed to navigate the ship using dead reckoning, which was standard practice in the days before modern navigation instruments like GPS.
During World War II, pitometer logs were often interfaced directly into warship fire control systems. This interface was necessary to allow gunnery and torpedo fire control systems to automatically track targets.
While the pitometer log is very commonly used today, there are a number of other logs that are also in use. These logs include:

Ships had a pitometer log to determine ship's speed that was integrated with the TDC. Why isn't this in Silent Hunter IV? Why isn't the sonar at its full complexity? Sonar in the game should be more advanced than presented in the game because it would be nice to be able to detect mines, marine mammals, etc. I just want a better way to calculate a ship's speed. I mean Nisgeis TDC has the ability to determine a ship's course, but not its speed.




http://en.wikipedia.org/wiki/Pitometer_log

All just MHO......

Simulations are Software, and software have limitations.
Yes.... Im sure there could be a "Magic Button" that tells you true target speed, but how "Real" would that be ?

I would almost be sure that even in real life that calculations made by Machine would be double checked by good old tracking methods so as not to waste the shot in case of error by the "Computer".... especially in that era ! ( Humans were slow to trust machines at that time. )

In any case......
Making marks on a map, and using a stop watch and ruler really does not take too awful much time..... 3 minutes ?
And if thats too long..... Time target for one minute, and multiply by 3 !

For me.....
Tracking is part of the fun !
In fact I cant remember using the TDC, I manual target and set the TDC up myself.
The challenge is in learning to estimate AOB, Course, and Speed without "Magic Buttons"..... so when the you light that Muther Up..... Pride of accomplishment is High.

Speed is the easy one to figure....... Range is a bit harder !

Anywyas...........

Just thought that I'd throw this in here. You cannot get a targets speed just by prop counting. While this does give you the shaft rpm of the target vessel, you still need to know what type of vessel it is. Knowing this, there should a know turns per knot (TPK) for that vessel. Once you have that information then you can make a speed estimate with sonar.

this sounds like a knot(ty) problem.

:har::doh:

In World War II we did not have data on these Japanese vessels as there was no way to study the ships to determine the RPM/speed curve for each ship. The only thing they could tell by the turn count was the relative throttle setting and whether the target was speeding up or slowing down. There was no connection made between RPM and speed.

What little information we had was for warships and I haven't seen a single record of a submarine encounter where prop counts were used as a speed determination. To do so here, even if it were possible, would be making a simulation into a video game.

What? It IS a video game?:D

The link posted earlier (http://www.maritime.org/fleetsub/sonar/chap4.htm) mentions this:
Would this have been included in the system just to determine if the target was changing speeds, or were they considering the possibility of using the data being collected to perform speed estimates? Or was there another reason they had dedicated part of the system to this? It seems to me that they wouldn't have used valuable space for a system they didn't intend to be used.

Currently reading Clear the Bridge and O'kane used prop counts extensively. He actually purchased a machine out of his own pocket to make counting the turns easier for the sonar officer before going out on Tangs Fourth patrol (I think it was 4th?)