Can't Remember Speed Formula

direland69 · 02-01-08, 04:24 PM

Hi all. Got a new PC and am ready to get back into SH4 after a little break. Someone posted a simple way to calculate target speed a while back but I can't seem to find it. Can someone verify if my memory on this is correct?

1. Mark first position reading
2. Wait some time (say 5 mins) and note it
3. Mark second position reading
4. Measure distance between readings
5. Speed = yards/seconds*2

Does this sound correct? What would the formula be if distance is in NM instead of yards?

Thanks!

Laconic · 02-01-08, 04:41 PM

I use three minutes with Imperial measurments. Mark the spot, wait 3 minutes, mark the spot, and measure. Knock two decimal places off of the measurement and you have your speed (so 900 yards = 9 knots). I usually cross-check this with the speed estimation button on the TDC and the speed given when I send in a contact report.

direland69 · 02-01-08, 04:50 PM

Quote:

Originally Posted by Laconic

I use three minutes with Imperial measurments. Mark the spot, wait 3 minutes, mark the spot, and measure. Knock two decimal places off of the measurement and you have your speed (so 900 yards = 9 knots). I usually cross-check this with the speed estimation button on the TDC and the speed given when I send in a contact report.

I like that. I'll try that too. Thanks for the tip!

Quillan · 02-01-08, 05:00 PM

Assuming you use metric measurements, distance covered in hundreds of meters = speed in knots if you time it for 3 minutes 15 seconds. I never bothered to figure out the time frame for Imperial measurements but it should be easy enough with a calculator.

1 nautical mile=1852 meters, and I think I'll go with this since SH4 is based around metric units with a built in converter to Imperial measurments. Assume a target is going exactly 9 knots, and you want to calculate the interval t where the distance covered in t time equals 900 yards.

9 knots = 16668 meters per hour.
1 hour = 60 minutes.
Therefore, 9 knots = 277.8 meters per minute.
1 yard = 0.9144 meters.
Therefore, 277.8 meters per minute = 303.8 yards per minute.
900/303.8 = 2.96 minutes, or 2 minutes 58 seconds to cover 300 yards.

Mark point on map, start stopwatch. Mark point again 2 minutes 58 seconds later. Measure distance between points. Distance covered in hundreds of yards is speed in knots.

This is, of course, assuming my math is correct.

Torpex752 · 02-01-08, 05:12 PM

Speed X 100 = distance travelled in 3 min

Distance travelled in 3 min / 100 = speed.

Frank

direland69 · 02-01-08, 04:48 PM

Disregard. It was in WernerSobe's Sonar Only Tutorial...

NM/Minutes*60 = Speed.

02-01-08, 04:24 PM	#1
direland69 Swabbie Join Date: Jul 2007 Posts: 7 Downloads: 7 Uploads: 0	Can't Remember Speed Formula Hi all. Got a new PC and am ready to get back into SH4 after a little break. Someone posted a simple way to calculate target speed a while back but I can't seem to find it. Can someone verify if my memory on this is correct? 1. Mark first position reading 2. Wait some time (say 5 mins) and note it 3. Mark second position reading 4. Measure distance between readings 5. Speed = yards/seconds*2 Does this sound correct? What would the formula be if distance is in NM instead of yards? Thanks!

02-01-08, 05:00 PM	#4
Quillan Samurai Navy Join Date: Apr 2005 Posts: 579 Downloads: 2 Uploads: 0	Assuming you use metric measurements, distance covered in hundreds of meters = speed in knots if you time it for 3 minutes 15 seconds. I never bothered to figure out the time frame for Imperial measurements but it should be easy enough with a calculator. 1 nautical mile=1852 meters, and I think I'll go with this since SH4 is based around metric units with a built in converter to Imperial measurments. Assume a target is going exactly 9 knots, and you want to calculate the interval t where the distance covered in t time equals 900 yards. 9 knots = 16668 meters per hour. 1 hour = 60 minutes. Therefore, 9 knots = 277.8 meters per minute. 1 yard = 0.9144 meters. Therefore, 277.8 meters per minute = 303.8 yards per minute. 900/303.8 = 2.96 minutes, or 2 minutes 58 seconds to cover 300 yards. Mark point on map, start stopwatch. Mark point again 2 minutes 58 seconds later. Measure distance between points. Distance covered in hundreds of yards is speed in knots. This is, of course, assuming my math is correct. __________________ We, the unwilling, led by the unknowing, are doing the impossible for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do anything with nothing.

02-01-08, 04:41 PM	#2
Laconic Soundman Join Date: Dec 2007 Posts: 142 Downloads: 109 Uploads: 0	I use three minutes with Imperial measurments. Mark the spot, wait 3 minutes, mark the spot, and measure. Knock two decimal places off of the measurement and you have your speed (so 900 yards = 9 knots). I usually cross-check this with the speed estimation button on the TDC and the speed given when I send in a contact report.

02-01-08, 05:12 PM	#5
Torpex752 Lieutenant Join Date: Mar 2006 Location: Deep River, CT Posts: 255 Downloads: 1 Uploads: 0	Speed X 100 = distance travelled in 3 min Distance travelled in 3 min / 100 = speed. Frank

02-01-08, 04:48 PM	#6
direland69 Swabbie Join Date: Jul 2007 Posts: 7 Downloads: 7 Uploads: 0	Disregard. It was in WernerSobe's Sonar Only Tutorial... NM/Minutes*60 = Speed.