A very fast Intercept Calculator
 

Assuming you have all the data already on your contact, I found a much faster way to construct the intercept than MOBO. (Aaron, this would be where the value of templates might give MOBO a lot of power to solve common reoccuring problems.)

Now, today, I have this process fully optimized. Although I worked out the MOBO construction of intercept with appropriate lead be unseen and submerge, I realized that I can use a much more straight forward special purpose calculator to solve the navigation problem. Originally, I thought this calculator, InterCalc, was only good for straight running torpedo solutions, but now I see it is ideal for setting up submerged submarine attacks.

In this screen shot, you see both the MOBO solution in the background with the same InterCalc solution in the foreground.

http://home.comcast.net/~markshot/tempimages/int08.jpg

Here is all the raw data needed to feed into either of these two tools:

http://home.comcast.net/~markshot/tempimages/int09.jpg

Suggestion: One thing your "I" intercept function is missing is the ability to specify a lead distance.

Actually, no. It's not missing.

In fact, not only can you plot a lead distance, you can also position yourself at a pre-specified attack station (something that intercalc can't do).

For a simple lead distance, all you'd need to do is plot another contact 20k yds ahead of the real contact and then plot the intercept for that second contact. I've included a way to set contact vectors equal (mouseover and press the equal key) for quickly adding stuff like that.

I frequently plot submerged intercepts to attack stations that set me up for 30° AoB at 2500yds.

Remember, maneuvering boards are used IRL for solving stationing problems. ...and if it can be done on a real moboard, it can be done on MoBo. I'm just leaving work, but when I get home I'll post your example with the 20k lead.

I understand what you just said with doing a simple lead. Yes, that would be better than what I did which was more trial and error of adjusting positions and looking at times.

I have try that "=" function.

Thanks.

Actually, I would like to see how to do that if you have the time or if it has been done already. Thanks!

Simple 20k Lead
 

Here's the simple example of the 20k lead applied to your plot example.

http://xl-logic.com/mobo/tutorial_pics/20kLead.png

I got 239° at 15kts for a 1:30 time to intercept.

Thanks.

2 Leg Attack Stationing
 

Now here's your original example with a little more complexity added. Let's assume we'd like to sneak in for a submerged attack at 4 kts. We need to put our boat in a position where it can make a 4 kt intercept on a target travelling 11.4 kts.

Starting with the original plot...
http://xl-logic.com/mobo/tutorial_pi..._Attack_01.png
We know an intercept on the surface at 15 kts is possible. But perhaps this is an armed or escorted merchant. We don't want to just blaze in on the surface at 15 kts.

So we start with a simple what-if scenario off to the side...
http://xl-logic.com/mobo/tutorial_pi..._Attack_02.png
Notice I'm just doing a little side calc here to figure out what my station would need to be for a successful 4 kt intercept. I see that a 20k lead and 20° AoB station would allow me to make my submerged approach.

Now I apply what I learned to my plot at the right...
http://xl-logic.com/mobo/tutorial_pi..._Attack_03.png
I plot a node for a 20k lead 20° AoB; this represents the relative position that I wish to achieve for target M1.

Now I plot a new contact on the stationing node and set the vector equal to M1 (with the new contact selected, hover over the M1 contact and press "=")
http://xl-logic.com/mobo/tutorial_pi..._Attack_04.png
With the new contact plotted, I can determine an intercept point for my desired 4 kt final approach. This is the first leg of the attack, a 15 kt surface run heading 235° for 1:04.

We know once we arrive at that first way point we can submerge and proceed at 4 kts. Oops, I forgot to figure out my final approach heading. Let's do that...
http://xl-logic.com/mobo/tutorial_pi..._Attack_05.png
The second leg is a submerged approach at 4 kts, heading 300°. A quick TSD calc on the 300° line reveals that we will be enroute about 45-50 mins before readying to fire. Plenty of time to quietly listen and fine tune our firing solution. Worth noting that you don't actually need to make it all the way to the intercept point on your submerged leg (unless your intention is to ram), so by default you've got a 1000-2000 yds of fluff in there, few extra seconds to double-check that solution.

Now you might also wonder, "Well, I know the distance to the contact was initially over 20k yards, and well out of visual range. But if I start closing that gap on the first leg of my surface run, will I be detected?" Basically, you want to know, "What is the Closest Point of Approach (CPA)?"
http://xl-logic.com/mobo/tutorial_pi..._Attack_06.png
The CPA is 16.4k yards. You shouldn't have a problem with visual detection. Notice how you determine CPA in a relative motion plot. It's the point on the target's projected path that is at 90° AoB to OwnShip.

Keep in mind, there are a lot of shortcut keystrokes that can make this a fast plotting process, but it's not unusual for attack plotting to take up a good bit of time. If you like that sort of thing, fine. Others may choose to shortcut the process and just make some estimates.


Edit: Actually, I see I made a common mistake in determining the CPA. :nope:
Do you see what's wrong with it?

Awesome tips!

From the screenshots and descriptions, MOBO looks like a very impressive utility! While I'm glad that someone is still finding my old InterCalc tool useful, it certainly appears that MOBO has taken the concept to another level of magnitude. I'll have to take a look at this thing sometime.


- David Sandberg (author of InterCalc)

Thanks for stopping by David. :up:

MoBo version 2 is presently in development. Any ideas/suggestions you might have would certainly be appreciated.

Awesome tips, every day I learn more about the MOBO :up:

No I don't see the mistake on the CPA. Lol I'm trying to do this very thing right now on a contact in SH 4. Be nice to know.

Thanks
Ed

What is the common mistake?
 

How about a hint? At first I thought it might have been 90S instead of 90P but the target's port side is facing our starboard side so looking at the target I see 90P.