Timing torpedo shots

Able72 · 03-31-24, 02:10 PM

Okay. I'm working with excel.

I am trying to build an excel spreadsheet to help with the timing of my torpedo shots in U-boat (although this would work equally well with SH3-5).

Assuming you know the following:
Range to target at torpedo launch
Speed of target at torpedo launch
AOB at torpedo launch
Speed of torpedo

I am trying to calculate the run time of the torpedo to impact with the target.

I can't seem to find the formulas I need. Anyone have links or helpful information? Thanks.

I know I need to solve the torpedo triangle problem, but I can't seem to figure out the angles and distances involved or find formulas to help me do this. Can someone help?

Able72 · 03-31-24, 08:27 PM

So...It took some digging and more frustration that I care to consider, but I finally figured out the answer to my problem. So I'm putting it here in case anyone else needs it or in case I delete the spreadsheet I made (again, don't ask).

If you know:
Range to Target
Target Speed
AOB
Torpedo Speed

The frustrating part about excel is that it calculates Sin, Cosin, Tan, etc, based on Radians, not Degrees. Therefore you have to employ the Radians and Degrees convertor in the right location to make the formulas work out. Using the values from the video below allowed me to check my formulas for accuracy.
Then you can calculate the following (formulas are for Excel):

Angle at Impact=180-(AOB + Lead Angle)

Lead Angle=DEGREES(ASIN(Target Speed*SIN(RADIANS(AOB))/Torpedo Speed))

Target Travel Distance to Impact=Range to Target*SIN(RADIANS(Lead Angle))/SIN(RADIANS(Angle at Impact))

Range to Impact=Range to Target*SIN(RADIANS(AOB))/SIN(RADIANS(Angle at Impact))

Time to Impact=Range to Impact/(Torpedo Speed*0.514444)

Mind you, these formulas are only useful for calculating the time to impact from torpedo launch (not gyro angles etc. and are closer to accurate the smaller your gyro angle).

These formulas also assume you are using the following units of measurement: Speed is in Knots and Distance is in Meters.

I found this video helpful in calculating this:

And this page helpful for solving the rest of the triangle: https://www.calculator.net/triangle-calculator.html

ReallyDedPoet · 04-02-24, 04:38 PM

Thanks for posting

XLjedi · 06-19-24, 07:17 PM

Although a couple months late to the discussion, I am truly touched seeing they used MoBo in the video.

...and glad the explanation in the video was helpful in your excel calc. MoBo started as a formula in a spreadsheet.

Would you like to see the rest of your excel calculation?
https://www.xl-logic.com/mobo/intercept_math.zip

Brings back fond memories.

03-31-24, 02:10 PM	#1
Able72 Captain Join Date: Mar 2008 Location: Somewhere in the North Atlantic Posts: 343 Downloads: 299 Uploads: 0	Timing torpedo shots Okay. I'm working with excel. I am trying to build an excel spreadsheet to help with the timing of my torpedo shots in U-boat (although this would work equally well with SH3-5). Assuming you know the following: Range to target at torpedo launch Speed of target at torpedo launch AOB at torpedo launch Speed of torpedo I am trying to calculate the run time of the torpedo to impact with the target. I can't seem to find the formulas I need. Anyone have links or helpful information? Thanks. I know I need to solve the torpedo triangle problem, but I can't seem to figure out the angles and distances involved or find formulas to help me do this. Can someone help? __________________ "Some ships are designed to sink, others require our assistance." Nathan Zelk

03-31-24, 08:27 PM	#2
Able72 Captain Join Date: Mar 2008 Location: Somewhere in the North Atlantic Posts: 343 Downloads: 299 Uploads: 0	So...It took some digging and more frustration that I care to consider, but I finally figured out the answer to my problem. So I'm putting it here in case anyone else needs it or in case I delete the spreadsheet I made (again, don't ask). If you know: Range to Target Target Speed AOB Torpedo Speed The frustrating part about excel is that it calculates Sin, Cosin, Tan, etc, based on Radians, not Degrees. Therefore you have to employ the Radians and Degrees convertor in the right location to make the formulas work out. Using the values from the video below allowed me to check my formulas for accuracy. Then you can calculate the following (formulas are for Excel): Angle at Impact=180-(AOB + Lead Angle) Lead Angle=DEGREES(ASIN(Target SpeedSIN(RADIANS(AOB))/Torpedo Speed)) Target Travel Distance to Impact=Range to TargetSIN(RADIANS(Lead Angle))/SIN(RADIANS(Angle at Impact)) Range to Impact=Range to TargetSIN(RADIANS(AOB))/SIN(RADIANS(Angle at Impact)) Time to Impact=Range to Impact/(Torpedo Speed0.514444) Mind you, these formulas are only useful for calculating the time to impact from torpedo launch (not gyro angles etc. and are closer to accurate the smaller your gyro angle). These formulas also assume you are using the following units of measurement: Speed is in Knots and Distance is in Meters. I found this video helpful in calculating this: And this page helpful for solving the rest of the triangle: https://www.calculator.net/triangle-calculator.html __________________ "Some ships are designed to sink, others require our assistance." Nathan Zelk

04-02-24, 04:38 PM	#3
ReallyDedPoet Canadian Wolf Join Date: Jul 2006 Location: Canada. The one and only, East Coast Posts: 10,817 Downloads: 946 Uploads: 5	Thanks for posting __________________ Back in the Day

06-19-24, 07:17 PM	#4
XLjedi Ace of the Deep Join Date: Jun 2005 Location: Palm Beach, Florida Posts: 1,242 Downloads: 53 Uploads: 8	Although a couple months late to the discussion, I am truly touched seeing they used MoBo in the video. ...and glad the explanation in the video was helpful in your excel calc. MoBo started as a formula in a spreadsheet. Would you like to see the rest of your excel calculation? https://www.xl-logic.com/mobo/intercept_math.zip Brings back fond memories. __________________ Last edited by XLjedi; 06-19-24 at 08:22 PM.