Intercept Convoy Questions

[Mersea]

Hello I am begining using the MoBo emb and it is impressive, the learning curve is step so I have questions.

a) Trying to intercept a convoy I got the bearing to intercept it, that is all, I surely miss a step, and when filling Data for Time nothing happens? I got the MoBo PDF but I have no printer so I must check it back, return to MoBo and got confused in the end; what about a text method to implement entries in the correct order, cause I surely invert entries at some points thus not having the expected result.

This is what I think about the "method" :

Intercept Convoy including Time (map scale is properly adjusted)

1. Place OwnShip ( I understand no entries except Time)
2. Place Contact (with speed and bearing and Time)
3. Tab space over Contact
4. Etc...

The Time I speak of is the Time of the "Screenshot" or Time of Contact reporting, letting MoBo knows my OwnShip position, and Contact position at this Time, so MoBo does compute the rest...


b) The course I got is direct into the convoy, the speed of my sub is calculated for surface, but the convoy and the destroyers would spot me long before reaching the intercept point. The submerged max speed is 9 Knots and batteries can't run for long "ride", so how to have an indirect course? also I understand that I can approach on surface at any speed and goes to periscope depth for the last run, but there we have two speeds eg: 17 Kts surfaced and 5 Kts underwater.


c) Is there a magnify tool? got struck with "long" intercept line and was unable to see its end clearly?


Thanks for your time

[XLjedi]

I think the mistake you're making is entering time for both ownship and contact when you're wanting the TSD to return time to intercept. Entering time at both nodes (or ownship and contact) will tell Mobo you have two observation times and you're trying to solve for speed, which isn't what you want to do.

For a simple intercept course solution, you don't need to adjust map scale or enter time to get an accurate intercept course.

Data Required:
1) Plot ownship position/heading/speed
2) Plot target position/heading/speed

Process:
After plotting ownship and target positions and motion vectors, hover cursor over target and press I to show intercept location (assuming intercept is possible). If nothing shows, then there is no intercept.

After you have the intercept plotted you can plot a node on the intercept location and connect it to ownship (hover over node and press spacebar) and then press B to display bearing. The bearing will give you both true and relative headings to intercept.



Intercept Tracking Node:
The InterTrack tool was added in an update that allows you to assign a node to track with the calculated intercept for any target. To assign a node to track with the target intercept point, right click a node and select InterTrack from the quickmenu, then select the target (not the intercept, but the target) you want the node to track. Now as you move ownship and target you'll see the node tracks with the intercept for the unit. The node will track the intercept point regardless of whether or not the target unit has the intercept displayed.

TSD Calcs:
If you want to do TSD calcs (time-speed-distance) to determine the time or actual distance until the intercept point you will also need the scale settings adjusted accordingly, which it sounds like you've already done. The TSD calcs require any 2 of the 3 elements in order to display the third. Now as a basic example, just leave the time as zero for ownship and add a node anywhere on the map and connect it to ownship. Hover the cursor over the node and press Y. This will show you the time it will take to cover the distance given ownship's speed. If you enter a time for ownship, it will adjust the time accordingly so if it takes 22 minutes to intercept and you entered 120 as the time, it will show you 1:44 as the time of intercept. If you left ownship time as zero, it would just display 22 minutes.

The other usage for TSD calcs is to plot two observation nodes and connect them to each other. This represents a distance traveled by a contact. You then enter a time for each of the nodes (hover over node and press T). Now you have distance traveled and time, so the missing component in the TSD calc is speed in this case. When you hover over one of the nodes and press the Y key it will tell you the speed.

[XLjedi]

Also, I documented the process in thread below which you might find helpful.

10th Patrol of U-53
http://www.subsim.com/radioroom/showthread.php?t=121786

You'll also see how I used the TSD feature to first determine the time to intercept, and then to figure out the target speed of 6kts.