[TMO] nav maps distance/speed charts

[DigitalAura]

Can someone tell me how to use the tools on the RIGHT side, where the various scales are in the TMO mod?
I can't figure out what they are for or how to use them?

[gAiNiAc]

What you do is draw a line from the target speed through the time scale and continue through the distance scale.......It's called a nomometer.....

[Frederf]

The nomometer is basically a static slide rule or calculator. When you draw a straight line through all three scales, the crossing points match up in a meaningful mathematical way. Draw a line through 30 minutes and 5 kts and I guarantee you that the line will also pass through the 5000 yd mark on the range scale, for example.

Hint: 0.5 hrs x 5 nm/hr = 2.5 nm (5000yd).

[Armistead]

If you ever plan to play with contacts off the nomo is the most important tool you can have....learn to use it.

[green_abobo]

If you ever plan to play with contacts off the nono is the most important tool you can have....learn to use it.

any suggestions on how you acheive this?

perhaps a link w/ screenshots and contacts that demonstrates?

so i can practice. its hard to read all the values because they're so tiny.

i understand the principle of it and realize why thats important. it's just the function and the procedures involved that has me perplexed. :o is it one line through the time,distance and speed variables? does this line have to be straight across, or can it be diagonal through the nomograph?

i'm also trying to learn how to use MoBo (v 1.2) as well. i know the basics. running the .exe file and using print screen to save nav map image to clipboard. apart from that.... i know nothing. there doesnt appear to be a readme file so i'm in the dark. any advice you can offer?

i'd appreciate it. :salute:

thanks.

[DigitalAura]

The nomometer is basically a static slide rule or calculator. When you draw a straight line through all three scales, the crossing points match up in a meaningful mathematical way. Draw a line through 30 minutes and 5 kts and I guarantee you that the line will also pass through the 5000 yd mark on the range scale, for example.

Hint: 0.5 hrs x 5 nm/hr = 2.5 nm (5000yd).


Perhaps you could give me (us) a practical application of this though, so that we might better understand why and when you would need to run a line through the "30 minute and 5kts" points. Thanks ! :-?

[tomoose]

Maybe this explanation will help. The nomograph/nomometer allows you to do quick calculations in order to determine information on a moving target.
For example;
you have a report of a ship at point 'X' heading NW at medium speed. I normally interpret 'medium speed' as 7 or 8 knots. So I have a rough posn on the map based on the report, a direction of travel (NW) and an approximation of speed. Let's say I want to know how far the target will travel in 2 hours. I use the nomograph and the ruler tool and click on 8knots and run a line to 2 hours (120 mins) the line will intersect a distance (I don't have the nomo so I'll say 10 miles for the sake of this example). Using this type of info you can calculate roughly where the ship will be (i.e. 10 miles further along his NW course assuming he doesn't change course or speed) and when (if your report states he was at 'X' at 1000hrs then your calc will put the ship 10 miles further NW at 1200hr) and conversely adjust your speed and course to get into a favourable position in time. This is all based on receiving a radio position report and admittedly is very rough. You'll still end up searching once in position but I've used it successfully to get ahead of a target then dive, listen and voila!! a distant sound of propeller coming from the right bearing. If you have a long distance visual then the nomograph can be used much more accurately to plan your intercept course etc.

Hopefully that didn't confuse things. I'm sure one of the experts here can probably expand (and correct) what I've said.:yep:

[DigitalAura]

Hopefully that didn't confuse things. I'm sure one of the experts here can probably expand (and correct) what I've said.:yep:

No, this is a very good illustration! Thanks moose!

[green_abobo]

Maybe this explanation will help. The nomograph/nomometer allows you to do quick calculations in order to determine information on a moving target.
For example;
you have a report of a ship at point 'X' heading NW at medium speed. I normally interpret 'medium speed' as 7 or 8 knots. So I have a rough posn on the map based on the report, a direction of travel (NW) and an approximation of speed. Let's say I want to know how far the target will travel in 2 hours. I use the nomograph and the ruler tool and click on 8knots and run a line to 2 hours (120 mins) the line will intersect a distance (I don't have the nomo so I'll say 10 miles for the sake of this example). Using this type of info you can calculate roughly where the ship will be (i.e. 10 miles further along his NW course assuming he doesn't change course or speed) and when (if your report states he was at 'X' at 1000hrs then your calc will put the ship 10 miles further NW at 1200hr) and conversely adjust your speed and course to get into a favourable position in time. This is all based on receiving a radio position report and admittedly is very rough. You'll still end up searching once in position but I've used it successfully to get ahead of a target then dive, listen and voila!! a distant sound of propeller coming from the right bearing. If you have a long distance visual then the nomograph can be used much more accurately to plan your intercept course etc.

Hopefully that didn't confuse things. I'm sure one of the experts here can probably expand (and correct) what I've said.:yep:

no, thats an excellent example. i have figured out how to use the nomo. to figure the contact's speed only.

with this example, i can now use it in reverse and plot where the contact's gonna be in what ever amount of time i choose,and can be there,set up, when it arrives. thanks.

[Frederf]

I think it's too easy to overestimate the complexity of the nomometer and treat it like it's some black voodoo magic. All it does is calculate time, speed, or distance if you know the other two things.

"How much time does it take to go a distance at this speed?"
Time = Distance / Speed

"How much distance is traveled by going speed for time?"
Distance = Speed x Time

"How fast does something have to go some distance within this much time?"
Speed = Distance / Time

These are the only three questions that the nomometer knows how to answer. If you want to know the course or angle or when the moon will rise, you need to look somewhere else. You ask by drawing a straight line through the two values you do know and the answer is discovered by finding where the line crosses the scale of the value you want to find out.

A practical example is (for me) commonly that I have plotted the target's location and I know its course and speed through previous calculations. I've decided that I want to shoot at the target when it gets to some specific future position since that makes for a good shot with short range and good angles. So I measure the distance from the target's current position to the desired future position and maybe it's 4600yd. Also say for example that the target is going at 8 kts. What I want to know is "How much time is it going to take that 8 kt ship to travel 4600yd?" This is important to me because I want to know how long I have to get into shooting position.

I pull out the ruler tool on the navigation map and I start a line from the 8 kt mark on the speed scale. I pull this line through the 4600yd mark on the distance scale until I cross the last scale, time. I notice that this line that passes through "8kt" and "4600yd" also passes through about 17 minutes. This tells me that something takes 17 minutes to go 4600yd at 8 kt.

Just for fun the problem can be extended. Using the previous result of 17 minutes until the target gets where I want him to be for shooting I discover that my submarine is too far away to make a shot. Oh no! Now I pick where I want to be to shoot which I measure to be 1200yd away from my current position. OK, I have 17 minutes to go 1200yd. How fast do I have to go? Leaving the right end of the line I made in the paragraph above at 17minutes, I drag the left end of the line around until the line crosses through 1200yd mark on the range scale. Then I look to the speed scale to figure out my unknown. The line crosses the mark at just over 2 kts. "I must go 2 kt to travel 1200yd in 17 minutes."

17 minutes later the 2 kt submarine has traveled its 1200yd and the 8 kt target has traveled its 4600yd. The nomometer has allowed me to arrive just in time.

[magic452]

Frederf's little tutorial is also useful when a convoy is changing course every 20NM. or so. Can I get a good position before they change or should I take a different track and attack after the course change?

Having time to set up for a good shot is the best way to get a good result.

Magic

[Frederf]

It's also nice to get the timing right to slip in the escort screen gaps or if you ascribe to the "can't sit at perfect periscope depth at 0 knots for days on end" realism.

[Rockin Robbins]

Actually it's a nomograph, not a nomometer. A meter is a mechanical device.

[DigitalAura]

Again, my hats off to you all. Wonderful application, Frederf! Thanks.

[Pisces]

Actually it's a nomograph, not a nomometer. A meter is a mechanical device.To be even more precise. It's a measurement device.

[Frederf]

Yeah, something seemed weird writing "nomometer." It's not really a measurement device (which is what the meter suffix would suggest) but a picture or graphic thus "graph."

[tomoose]

Frederf's explanation is spot on. I had forgotten to mention that the nomograph can help you figure out your own speed/time in order to get to the right spot.

As Frederf says the nomograph gives 3 pieces of information (speed, time, distance), if you have two pieces of that info the nomo will quickly and easily give you the third.

For what it's worth; you'll get to instinctively know what "slow", "medium", "fast" means which will help you pick a speed. I always use 5 knots or less when I get a "slow" report. Having said that I always add a couple of knots to my speed 'guess' so that I have more chance of being ahead of an intended target (i.e. calculate he's moving faster than he actually is and you'll theoretically get there well ahead of him) and then I'll head back down the enemy's plotted course and hopefully intercept. It generally works well but not always as the target could change course, even slightly, and that'll throw things off, but you have to take that chance. No guts, no glory, LOL.:salute: