How to intercept?

[Pisces]

You multiplied your speed and his speed by 10. So the circle is now 170 km for your 17knots intercept speed. This won't work because you are too close. You have to extend the line between you and the target to beyond your position behind you to make it work at these proportions. The circle will intersect the line on the extension behind you. But instead it is easier and more foolproof to make your drawing on a 1 km to 1 knot basis.

[P_Funk]

Originally Posted by Pisces

You multiplied your speed and his speed by 10. So the circle is now 170 km for your 17knots intercept speed. This won't work because you are too close. You have to extend the line between you and the target to beyond your position behind you to make it work at these proportions. The circle will intersect the line on the extension behind you. But instead it is easier and more foolproof to make your drawing on a 1 km to 1 knot basis.

Exactly this. I always used to have this problem in the past. I'd keep getting bad solutions and wondering if there was just an arrangement of ship to contact that made it not work properly, then I realized the stupid meat bag behind the keyboard was the problem.

[Pistoliero]

Are there any benefits to using so complex intercept algorithm?
Ruler and knots to km/h transfer sheet (seite 1) work just fine for me.
All you need in this case is to draw target course vector and find (on this vector) a point, to which your u-boat will arrive before the target will.

[maillemaker]

]Are there any benefits to using so complex intercept algorithm?

I just use the nomometer on the right-hand side of the screen.

Steve

[Pistoliero]

Originally Posted by maillemaker

I just use the nomometer on the right-hand side of the screen.

Steve

Actually quite awesome tool. I didn't know it is functional before this thread - thought that it is purely decorative.
Thanks!

[LGN1]

When you master the regular interception and use GWX or NYGM, you can use this to make an interception more challenging:

http://www.subsim.com/radioroom/down...o=file&id=3306

Now the speed and course are no longer exact and you have to guess more.

Regards, LGN1

[Pisces]

Originally Posted by Pistoliero

Are there any benefits to using so complex intercept algorithm?
Ruler and knots to km/h transfer sheet (seite 1) work just fine for me.
All you need in this case is to draw target course vector and find (on this vector) a point, to which your u-boat will arrive before the target will.

The algorithm is a geometric method. You'll get the (precise) answer in a fixed number of steps. Some prefer that because they can handle graphical representations better then numbercrunching.

Yours is a bit more trial and error in predicting where the target will be in x hours and minutes, then calculate yourself or use the waypoint marker to find out where you will be. And hopefully they match to a point. Depending on how good you are in it, you can get this in one or too steps. But to each their own preffered method.

[scott_c2911]

I used to use the nautical miles to kilometers conversion table supplied with gwx to calculate distances travelled but I played the game so long now that I almost instinctively plot intercept courses now. They are tabs kept on the top left hand corner of the chart table. I always plot them so I have enough time to get into position and set up for the attack. Early war i stay up and give em a broadside so finese isnt as critical then but late war you need to be submerged for nearly all attacks.

[vanjast]

Originally Posted by Pistoliero

Are there any benefits to using so complex intercept algorithm?
Ruler and knots to km/h transfer sheet (seite 1) work just fine for me.
All you need in this case is to draw target course vector and find (on this vector) a point, to which your u-boat will arrive before the target will.

Eggsactly.. then you turn down the course to the expected convoy, putting you in perfect 'convoy infiltration' position, if you're lucky just within the outer column/row.

This you do submerged at depth depending on convoy speed, tracking the 'convoy spread' on hydrophone, to assess your position. Once the lead escort passes over you, you start surfacing - should bring you up approximately in the first row or just after.

The juicy targets are mid-convoy.
Los

[BigWalleye]

Originally Posted by vanjast

Eggsactly.. then you turn down the course to the expected convoy, putting you in perfect 'convoy infiltration' position, if you're lucky just within the outer column/row.

This you do submerged at depth depending on convoy speed, tracking the 'convoy spread' on hydrophone, to assess your position. Once the lead escort passes over you, you start surfacing - should bring you up approximately in the first row or just after.

The juicy targets are mid-convoy.
Los

Small problem: the contact heading is only accurate to +/- 12.75 degrees. A contact reported as "Heading ENE" (ENE= 67.5 degrees) could have an actual heading anywhere from 56.25 to 78.75. If it takes you ten hours to reach the intercept, then the area of uncertainty is 50 km wide. Using a 16 km horizon, if you simply head straight down the reciprocal heading, there is a 30 percent chance you will make visual contact, provided the contact doesn't change course.

[Zosimus]

The only easy solution to that is to intercept the ship/convoy as quickly as possible. Full/flank speed with battery recharge off and prefer contacts that are closing.

[desirableroasted]

Originally Posted by Zosimus

The only easy solution to that is to intercept the ship/convoy as quickly as possible. Full/flank speed with battery recharge off and prefer contacts that are closing.

Since nothing, other than a task force, moves at more than 9kt, racing off at flank speed is a fool's errand. Especially since "East" is vague and since (in GWX at least) ships and convoys can and do change course.

If I can reasonably reach an intercept point within 4-5 hours, without turning my mission inside out, I will. Can't hurt, right? But banging off 10-12 hours a full flank.... tried that many times. Not worth it. And, yes, I am an ace at trigonometry, but the game simulates uncertainty very well.

The point is to conserve fuel so as to have as long a patrol as possible. More time on the lake, more targets, more kills. Zipping around every time BDU burps is the fastest way home with nothing in the bag.

[banryu79]

Originally Posted by Zosimus

The only easy solution to that is to intercept the ship/convoy as quickly as possible. Full/flank speed with battery recharge off and prefer contacts that are closing.

When I receive a distant radio contact from BdU I do the following, just to tackle with the issue highlithed above:
1) mark down the contact reported position.
2) with the ruler plot 3 possible course: the 'exact' one and the two '+10°/-10°' courses.
3) On each course I mark down the theoretical position of the contact for each hour passed since contact position reported hour (I choose the highest among the possible theoretical contact speeds).

Then I plot I circle of 22 Km radius (max hydroph. range) and move it as farthest along the three plotted routes as possible till it still can intercept all three course-lines.

That is the maximun "area" along contact path I want to be able to intercept in time, so given my position and the total estimated time needed for the contat to get to that "area" I plot my intercept run and I'm able to compute the minimum speed I need to run.

With that "minimum speed to intercept" on my hands I can evaluate if, where, when and at which speed to actually intercept that contact. I usually do well with this method, and I rarely need to run at "ahead full" (Type VIIB) let alone "ahead flank".
My tipical intercept run speed is in the range 9-12 knoten.