Aim when the sea ripples and rolls ( ? )

Teed · 01-17-14, 11:02 AM

Manuals on SH IV forum show a procedure of taking aim exclusively on the calm sea. Periscope and TBT are motionless. Easy task.
However when the sea ripples and rolls, TBT swings intensely. Up and down, up and down. How can I measure the distance with a stadimetre ? One needs to be than deft...
In that situation all that is left are the binoculars ?

Teed

aanker · 01-17-14, 12:44 PM

I rough it in and plot, plot, plot, and plot to determine course & speed, and continue to take readings and plot to fine tune the plot. I try to set up the shot to fire with a zero gyro at the position the target will be, calculating this by knowing the speed of the torpedo and the speed of the target.
By this time I have lines and circles (arcs) all over my chart and know when the target reaches a certain point on its course it is time to fire. My periscope is always pre-set to this point, so many degrees to port or stbd.
My boat is moving forward at 1.5 - 2 kts and this doesn't matter if the distance is under 1,500 yards, preferably under 1,000.
If 2 targets, I try for simultaneous detonation and usually succeed.
This is the method used on S-Boats that didn't have a TDC I learned from reading Frank Kulick's description:
http://www.valoratsea.com/notdc.htm

Happy Hunting!

TorpX · 01-18-14, 12:46 AM

My tactics are similer to aanker's.

If you are plotting in conditions that make for large error margins, then you must make more observations and "fair the plot", to obtain good data. In effect you will obtain average values of speed, course, and range.

If, for example, you are operating in difficult conditions, and you estimate the observed speed error to be, after 3 observations, to be 20%, then if you instead make 12 observations, you could expect the error to be reduced to 10%. Real-life crews usually had to do this anyway, as the stadimeter was limited in it's accuracy, positive identification of ships was problematic, and ships were often zigging.

Teed · 01-20-14, 06:35 AM

I thank for answer.

* You is right TorpX “Real-life crews usually had to do this anyway, as the stadimeter was limited in it's accuracy.” Therefore only some torpedoes hit...
That is near rough sea, as in life - work,work,work. It lets however effect.

* http://www.valoratsea.com/notdc.htm - Very interesting material. I wanted always to know as they did this really. Without TDC and calculator.

Teed

01-17-14, 11:02 AM	#1
Teed Swabbie Join Date: Dec 2011 Posts: 12 Downloads: 114 Uploads: 0	Aim when the sea ripples and rolls ( ? ) Manuals on SH IV forum show a procedure of taking aim exclusively on the calm sea. Periscope and TBT are motionless. Easy task. However when the sea ripples and rolls, TBT swings intensely. Up and down, up and down. How can I measure the distance with a stadimetre ? One needs to be than deft... In that situation all that is left are the binoculars ? Teed

01-17-14, 12:44 PM	#2
aanker Pacific Thunder Join Date: Apr 2004 Location: Yellow Sea Posts: 1,896 Downloads: 236 Uploads: 14	I rough it in and plot, plot, plot, and plot to determine course & speed, and continue to take readings and plot to fine tune the plot. I try to set up the shot to fire with a zero gyro at the position the target will be, calculating this by knowing the speed of the torpedo and the speed of the target. By this time I have lines and circles (arcs) all over my chart and know when the target reaches a certain point on its course it is time to fire. My periscope is always pre-set to this point, so many degrees to port or stbd. My boat is moving forward at 1.5 - 2 kts and this doesn't matter if the distance is under 1,500 yards, preferably under 1,000. If 2 targets, I try for simultaneous detonation and usually succeed. This is the method used on S-Boats that didn't have a TDC I learned from reading Frank Kulick's description: http://www.valoratsea.com/notdc.htm Happy Hunting! __________________ " Bless those who serve beneath the deep, Through lonely hours their vigil keep. May peace their mission ever be, Protect each one we ask of thee. Bless those at home who wait and pray, For their return by night and day."

01-18-14, 12:46 AM	#3
TorpX Silent Hunter Join Date: Sep 2010 Posts: 3,975 Downloads: 153 Uploads: 11	My tactics are similer to aanker's. If you are plotting in conditions that make for large error margins, then you must make more observations and "fair the plot", to obtain good data. In effect you will obtain average values of speed, course, and range. If, for example, you are operating in difficult conditions, and you estimate the observed speed error to be, after 3 observations, to be 20%, then if you instead make 12 observations, you could expect the error to be reduced to 10%. Real-life crews usually had to do this anyway, as the stadimeter was limited in it's accuracy, positive identification of ships was problematic, and ships were often zigging.

01-20-14, 06:35 AM	#4
Teed Swabbie Join Date: Dec 2011 Posts: 12 Downloads: 114 Uploads: 0	I thank for answer. * You is right TorpX “Real-life crews usually had to do this anyway, as the stadimeter was limited in it's accuracy.” Therefore only some torpedoes hit... That is near rough sea, as in life - work,work,work. It lets however effect. * http://www.valoratsea.com/notdc.htm - Very interesting material. I wanted always to know as they did this really. Without TDC and calculator. Teed