fast calculate speed ship with periscope

Macardigan · 03-09-13, 07:27 PM

hi,
im from spain, bad english.

1. enemy ship moving at 90ºAOB ~aprox. (side view).
2. Put vertical line of periscope on bow ship and activate stopwatch.
3. When the stern reaches the vertical line.. stop the timer.

then:

Ship length
----------- X 1,85 = Speed in Knots.
time in sec

example:

cimmaron class tanker= 190,6 m (length)
time bow--->stern in sec= 38 seconds.

190,6 m
-------- X 1,85 = 9,27 Knots
38 sec

easy.

Fifi · 03-09-13, 07:34 PM

Hey, that's interesting and good to know!
...But as you need to be almost 90° angle, by the time you make your calculation and enter it in TDC, ship is in bad position to fire torp...meaning you're not anymore in ideal 90° position for best hit without DUD torpedo...

Macardigan · 03-09-13, 08:15 PM

It is assumed that you already have all the calculations for firing solution, but the speed does not convince.

Do not have time? 30 or 40 seconds, divide and move the speed at tdc. It's fast.
If you shoot when the ship passes through 0 degrees, you can do 10 or 15 degrees before.

I always have time. And if the ship is far more better because you will see more time aside.

It is not necessary that the vessel is 90 ° accuracy.

You need to see the entire length and that's enough.

you'll get used.

greetings.

Fifi · 03-09-13, 08:47 PM

Thanks for the tip, i'll try it

finchOU · 03-09-13, 09:55 PM

Get your slide rule ready for realism!!! haha

Fifi · 03-09-13, 11:28 PM

Macardigan, it's working quite good

For a liberty ship going 6 knots at 1500m from me, i found 5.75 with your method.
Just have to round number up, and it's fine.

03-09-13, 07:27 PM	#1
Macardigan Engineer Join Date: Mar 2012 Posts: 219 Downloads: 199 Uploads: 0	fast calculate speed ship with periscope hi, im from spain, bad english. 1. enemy ship moving at 90ºAOB ~aprox. (side view). 2. Put vertical line of periscope on bow ship and activate stopwatch. 3. When the stern reaches the vertical line.. stop the timer. then: Ship length ----------- X 1,85 = Speed in Knots. time in sec example: cimmaron class tanker= 190,6 m (length) time bow--->stern in sec= 38 seconds. 190,6 m -------- X 1,85 = 9,27 Knots 38 sec easy.

03-09-13, 09:55 PM	#5
finchOU Samurai Navy Join Date: Jan 2004 Posts: 571 Downloads: 77 Uploads: 0	Get your slide rule ready for realism!!! haha __________________ Intel i7-2700K-3.50GHz, 16 GB RAM, 2 xGTX 560,2GB,SLI,2 TB HD The Wolves of Steel 1.06 The Wolves of Steel 1.06 Update 05c

03-09-13, 07:34 PM	#2
Fifi Navy Seal Join Date: Dec 2012 Location: France Posts: 6,092 Downloads: 466 Uploads: 0	Hey, that's interesting and good to know! ...But as you need to be almost 90° angle, by the time you make your calculation and enter it in TDC, ship is in bad position to fire torp...meaning you're not anymore in ideal 90° position for best hit without DUD torpedo...

03-09-13, 08:15 PM	#3
Macardigan Engineer Join Date: Mar 2012 Posts: 219 Downloads: 199 Uploads: 0	It is assumed that you already have all the calculations for firing solution, but the speed does not convince. Do not have time? 30 or 40 seconds, divide and move the speed at tdc. It's fast. If you shoot when the ship passes through 0 degrees, you can do 10 or 15 degrees before. I always have time. And if the ship is far more better because you will see more time aside. It is not necessary that the vessel is 90 ° accuracy. You need to see the entire length and that's enough. you'll get used. greetings.

03-09-13, 08:47 PM	#4
Fifi Navy Seal Join Date: Dec 2012 Location: France Posts: 6,092 Downloads: 466 Uploads: 0	Thanks for the tip, i'll try it

03-09-13, 11:28 PM	#6
Fifi Navy Seal Join Date: Dec 2012 Location: France Posts: 6,092 Downloads: 466 Uploads: 0	Macardigan, it's working quite good For a liberty ship going 6 knots at 1500m from me, i found 5.75 with your method. Just have to round number up, and it's fine.