Hi Joe S,

45 degrees is just a point at which the target's lengt is about 75% of what it would be broadside, but you also get the added advantage that 70% of the target's speed gets added to the closing speed of your torpedo, which is a big help. The 45 degrees works even better if you use a spread from aft to bow, as all the torpedoes arrive at the same time.

You can use this method though to attack any angle you want, even from behind.

Thanks for saying about that method you use and yes, it's essentially the same procedure you used to use on Sub Battle Simulator (sounds great :-). The only slight difference is, this is slightly simplified. All we need to find is the ratio between the two closing distances. For that, where you are using distance target travelled, versus distance torpedo travelled, we are taking that equation and simplifying it just a bit.

We are trying to find the angle formed by the two distances travelled, prior to collision for an unspecified unit of time. Your method of using distance travelled by target and distance travelled by the torpedo is great and will give you the correct answer. We can simplify that a bit though, as speed = distance * time for both target distance travelled and torpedo distance travelled, then we can say that the time component of each equation is the same. So, we can substitute it for a value of one. Thus the ratio between distances travelled becomes the ratio between speeds. That simplifies things a bit, as we don't have to work out how far things have travelled, only how fast :|\\.

Do you still use this method? If so, does it still serve you well?

[quote=Munchausen]After thinking about it awhile, I realized this method can be done at any angle, without using the TDC at all ... but (I think) I did it bass-ackwards. Here's what I did, using RR's single mission scenario.

<SNIP Excellent Tutorial>

So, was that bass-ackwards or what?[/quote

Munchausen, that was a brilliant example. You even measured the angles to the ends for extra accuracy :|\\. That's exactly how it's meant to be.

For those that have asked why use the TDC, the answer is you don't have to at all, but if you do put AoB and the bearing into the TDC and ask it what it thinks, it should say zero gyro angle, if it doesn't then you've done something wrong - probably either drawn with the wrong torpedo speed, or you haven't selected the right torpedo speed in the torpedo panel. It may be useful as a double checking aid. It's a bit trickier to work out the AoB in your head, but it's just 180 - target and torpedo intersection angle - the bearing your drawing gives you. That's based on a bit of maths that says all angles in a triangle add up to 180 degrees, so if you know the intersection angle (angle 1) and the bearing you shoot at (angle 2) then the AoB (angle 3) must be (180 - angle 1) - angle 2.

There's only one thing I can add to that Munchausen and that's you could try using the plot navigation course tool to plot your course beyond the target's track. That way you will be able to measure from that, instead of having to draw it.

You can use this method for any attack angle and drawing the speeds over the setup the way you have done really does simplify things, with the use of the course plotting tool, excellent addition! Thanks for taking the time to post that Munchausen! Every bit of discussion helps to generate new ideas. Fantsatic.

OK, I promise to stop spamming now.

One question, should the time be 3 minutes 15 seconds for Imperial? I am getting the wrong speeds. I peeked in mission editor after missing several times. It works but the tanker in the posted single mission keeps turning and the fish go right by him.

Peabody

3 Minutes for Imperial, 3m15s for Metric. It works because...

If you wanted to count the herd by counting the legs and dividing by 4, you could measure 3 minutes (we'll call that d), multipy that by 20 (to get yards/hour) and divide that by 2000(to get knots).
Knots = (d*20)/2000.
Of course, if you're a good mathematician, you say "Wait, we can simplify that!" It simplifies to Knots = d/100.

I'm not familiar with the metric knot, so I can't show you exactly why 3m15s works. But it's the same principle at work.

You think it's an accident that the demo movie is in a driving rain? http://i196.photobucket.com/albums/a...leys/winky.gif

With a longitudinal spread, turning into the attack is a very simple way to avoid because the topedoes all take the same track to the target. Later, when we crank up the PK and shoot the stern, MOT, bow divergent spread, the torpedoes run side by side to the target and life isn't so easy for Mr Tanker.

A weakness of the John P Cromwell attack is that he's only 45º from the bearing of the torpedo. He's already halfway into the turn to avoid. Electric torpedoes or night/bad weather shots are good here.

There is no metric knot. Those crazy Europeans, knowing the imperial system is so superior, cannot resist using the knot, because like all imperial measurements it actually relates to something useful (in this case, the circumference of the earth and the number of nautical miles (another more useful imperial unit!) in of one degree of latitude). Kilometers per hour, on the other hand, is so unusually useless, even for a metric unit(!), that they have discarded it in favor of something that actually works for navigation. Imagine that! Using the knot is their one consession to sanity.:rotfl:

3:15 works for metric because the yard is 36" long, the meter is 39.37". It is longer, so you need a longer time to measure it. 3:00/36 =3:15/39.37.

I'll double check, I may have had it set to metric because of the JP campaign, but I was getting incorrect speeds on the tanker. So it is probably my fault. I just remember on another thread one was 3min one was 3min15sec, I just didn't remember which and I did get the correct speed using 3min15sec.

Thanks for the answer.

Peabody

Actualy the 'naut and (kilo)meter is based on the exact same baseline( 1 quarter of the the pole-equator circumference), just each a different division. Naut's follow the degree-minute division. A kilometer is defined to be one 10,000th of that quarter circle. Or more correctly a meter is one 10 millionth of the quarter-'circle'. Apples and oranges... are both spherical.

3 minutes 15 seconds works because 3600 seconds (1 hour) divided by 18.52 (# of times 100 meters go into a nautical mile) is 194.38 seconds. Rounded to an easy measure that is 3min 15sec.

[quote=Pisces]Right, I knew there was some sort of mathy ratio behind it, I just couldn't recall what it was. Thanks guys!

And that's all fine and good but the Frenchies screwed the pooch (technical term there) and got their measurement way off. The meter ended up having no relationship to the size of the earth at all and now is just a bunch of bars of metal of varying lengths themselves, sitting in various places. They spent lots of time deciding (that means fighting about) which one was the "authentic" meter (who cares? They got it WRONG to begin with:rotfl::rotfl:) and then redefined the meter as a number of wavelengths of a certain frequency of light. THAT'll fix 'em!

So the entire metric system is based on a surveying mistake! Somehow that is very appropriate. Perhaps it's relationship to human error is the most appropriate measurement of all!

I did that yesterday when demonstrating the technique to my daughter's boyfriend. Using the "plot course" tool, the trick is to let your sub turn until rudder is centered ... then you can draw your "hypothetical" triangle and get the offset (lead) angle without even measuring your own course ('cause the tool's line is your sub's course line). You can even continue to close on the target's track ... just so long as you don't change course.

:up: This is certainly the way to go if your TDC is broken ... or you're the skipper of a WWI U-Boat.

Hi all i have just started with manual targeting with the excellent Dick O Kane method and i've had some fair success so far and i am keen to try this new one but one thing i've a problem with is getting accurate speed estimates my nav map dividers measure in tenths of nautical miles rather than yards and this throws me a bit is this a setting or a mod that i need to get yards ?

Hi BlackBob, welcome aboard! The only reason I can think of for having measurements in tenths of a nautical mile, is if the distance is over 10,000 yards (or 5 nautical miles). Up until that distance, the measurements are in 100s of yards, up to 10,000 yards, over 10,000 yards, the measurments are in tenths of nautical miles.

Thanks Nisgeis but even if i zoom in the units remain the same i can measure down to 0.1nm i've just realised that i am only patched to 1.3 could that have any bearing (sorry terrible pun)

Perhaps, I'm not sure as 1.3 is a very old patch, you should be on at least 1.4, or SH4 1.5 which is the U-Boat Missions add-on as well (don't call it a patch though, or LukeFF will kill you!)

I've got the U Boat add on coming this week so i'll stick to shooting things from 90 until it arrives thanks very much for your help

Hello Nisgeis,

I used that method with Sub Battle simulator because it was the only way to aim torpedoes. The sim did not have a functional tdc, and the manual said to point the periscope and shoot, which only worked for a stationary target. At the time, I assumed that the boat needed to remain stationary, but now , after doing much more work with fire control problems in SHI,2 3 and 4, I believe that your boat could be on the move, as long as your boat and the target stayed on course and did not change speed. I wish I had realized that way back then. Sub Battle Simulator was primitive by today's standards, but the gameplay was the equal of anything we have had since. At any rate, I have not used that method with SH4 due to the fact that we have a functional TDC, which is safe and effective when used as directed. the single most effective element of any fire control solution is target speed, and if you have calculated the target speed accurately you should be able to consistently get hits, no matter what method you use.Theoretically, one could use this "new" method even if your periscope is destroyed if you can get a speed estimate while on the surface, then submerge and wait in ambush, and use the hydorphones to detect the firing bearing of the target. I have not tried it but in theory it should work. Thanks for all your help and work with this, it adds to the knowledge base and gives us additional options. Joe S

Well, since the earth isn't a perfect sphere but more like a ellipsoid(the reason that 'original french' meter was incorrectly measured), so too a nautical mile lacks concrete definition. Both suffered from the same misconceptions. Infact the nautical mile is now defined to be 1852 meters. Neither is more true than the other.

A fine try there. But the Germans themselves say the knot is a better unit, because they chose to throw out the kilometer and use the knot for its usefulness in navigation. Who am I to contradict their good sense?:rotfl:In this case "true" is what works!

Isn't it weird that the Internationals actually succeeded in defining a preexisting measurement with one derived improperly later!? This is a farce, but what do you expect from people who can't properly measure the earth? The nautical mile is at most a little under 1% off at certain places on earth.

Metric measurements are based on non-human parameters (1/10 millionth of the distance between the equator and the pole, 100th the distance between freezing and boiling water, other alien measurements), and as such are not suited to measuring things that humans use, or even humans themselves.

Imperial measurements are based on useful things to do, or on a rough relationship to dimensions of the human body. This makes them much more appropriate for human use. The only thing the metric system has going for it is its decimal nature. But it is intrinsically alien and possibly evil.:doh:

THAT's what Europe needs: an exorcist!:rotfl: