3 minute 15 second rule?
 

What is the 3 minute 15 second rule?

Also, I did a dry run with 280° @ 4000 yards (A) and 283.5° @ 3200 yards 195 seconds later. I have 1.5 SHIV w/RFB -TMO so contacts are present, so I had 'general' ranges. Stadimeter and me do not seem get along even with SCAF that is integrated into RFB. Definately not at these ranges.

According to my calculations, observation A has an AoB of 13.5° and observation B has an AoB of 17°. Correct me if I am wrong on any of this please.


With a difference of only 3.5° I could not go down far enough on the standard S scale (<6-90). I got stuck. Now I presumed that I could use ST and read from the D. This gave me the number 8.35. I figured I needed to move the decimal over once more to the left. I wind up with 835 units/yards. Measuring on my map between my two marks gave 850 aproximately. While this seems close, there are a heckuva' lotta' numbers on this thing! confirmation would be greatly apreciated.

At this stage I'm sorta' lost in decimal transitions. I then slid 1.95 (seconds) on the C scale to .835 (units/yards) on the D scale (the very left of it). The right hand index mark of the C scale pointed to 9.4 (units per second) on the D scale.

So, now for the 'prestige'. I slide 5.6 on the C scale to 9.4 on the very, very left of the D scale and get my right hand C index at 9.4 (knots).

So now that I have typed all of this, I get the feeling that the '3 minute 15 second rule' means i do not have to translate 'units' to 'knots'. Needless to say I could still use some clearification on the moving of the decimals if nothing else.

Thanks in advance,
Mr Sargyano

PS I am currently useing the slide at http://www.antiquark.com/sliderule/s...tual-n3-t.html

My new Pickett slide rule
 

Pretty nice. Now if it would only help me shoot straighter ;).

My new Pickett N-500-ES slide rule

Howdy, MrSargyano.

The 3:15 min rule is to metric measure as the 3:00 min rule is to imperial measure.

Mariners use these rules to determine the speed of another vessel under their observation.

E.g. If it is determined that an observed vessel travels 0.8 km in 3:15 min., then,

the observed vessel's speed = 8 kn. If 1.5 km, then 15 kn. etc.

Imperial: Distance (yds) in 3:00 / 100 = speed in knots.

-...-

btw, nice Pickett :up: sweet.

Go here.......http://oughtred.org/flyers/OS-ISRM_SlideRuleSeminar.pdf for a PDF
D/L


steinbeck..........:yep:

Excelent.
 

Good rules to know Don1reed! The more ways I know to find a solution, the more options I have when I need to calculate one. Not to mention give myself a sanity check if necessary.

Steinbeck, I will make a point to go over the one you have suggested to Jmr before I finish reading the two I have chosen. I have at this point found alot of sites on the slide rules and downloaded a select few PDFs after having perused many. Ought to be fun if I could just stop reading these forums and playing the game long enough to read them :know:. Fortunately, my in-game targeting has become sufficient enough that when I start practicing with the slide rule again, I will have a good point of reference.

Soon I will get rid of the box on the map (RFB w/o TMO) that marks the target locations. Wihtout that, things will get difficult once again. I use them to calculate AoB, speed, and verify solutions. All three of these things are easy as long as they are present. Even distance isn't terrible to calculate with them.

Measuring distance with the stadimeter (minutes of angle w/SCAF mod) will become critical at that point. SONAR will be my only available sanity check (that I know of) and it will not allways be available (surfaced) or sometimes even an option (DD's) let alone entirely accurate :rotfl:.

The challenge awaits.

Thanks ya'll,
Mr. Sargyano

PS I can tell allready this is going to be a great doc for me Steinbeck.

Or, unless you had one of these little bad boys!!!
http://www.youtube.com/watch?v=HYsOi6L_Pw4