O'Kane (or maybe it was Calvert ... the books are all back at the library now) missed a shot one night (during a surface attack) and surmised that it was because he'd gotten the speed wrong. This was his second or third target and, evidently, the convoy had either sped up or slowed down. He never mentioned target course. Ergo, I suspected he was eyeballing AOB.

Awhile back, somebody else at this forum mentioned how you could shoot a 90 degree AOB without actually having your sub pointed perpendicular to target track ... the comment kind'a went unnoticed. But, putting two and two together, I figured it would best explain how a skipper could take on multiple targets, at night and on the surface, and miss only if he got the speed wrong.

Unfortunately, night surface attacks are hard to do in SH4. I've read where gray-painted subs could sometimes get within 500 yards of a target without being detected. If there's a mod that simulates this, I'd like to know about it.

Not all convoys scatter, I attacked one last night and the 1 damaged tanker, and the only un-hit merchant (4 ships with a MS and an XPC escorting) steamed on at 7 knots while the 2 I stopped, foundered.

Just wondering if this method was ever cataloged and had any videos created?

dropping in
 

thought I would drop in and show off my newest sig. Waves to RR, Nisgeis, and all.:D

Very nice, but you should put the text part in italics:cool:

I don't think so.

:cool: I've been using this method exclusively in SH3 ... after installing MaGui (it has a button on all applicable 2D screens to switch from manual to auto TDC). The method really works great for surface attacks ... especially after you've blown your O'Kane-type setup. Just put the TDC in manual mode, input target speed (you still must figure that one out yourself), set an AOB of 90 degrees, WAG an intercept course, lock your target, wait until it's in profile, press the button for auto, and fire a spread.

As long as you're in manual mode, the target's AOB will remain at 90 degrees. As long as you're locked (and in manual mode), the scope/UZO will maintain azimuth ... but the TDC bearing won't move. Switching to auto-TDC just before firing sets the TDC bearing to your target's current azimuth ... while leaving the AOB at 90 degrees.

:/\\k: In other words, you now have a proper firing solution. If your target's speed is correct, you can even unlock and delay firing so as to pick your sweet spots.

For Fleet boats, it's a bit more complicated. The TDC works differently.

Unfortunately in SH4 you either have manual or auto, you cannot change once you start a patrol.

:-? I think the problem with Fleet boats was, when locked on a target in Manual mode, sending a bearing to the TDC also changed the AOB. If the AOB Mod freezes the target's AOB (until PK is activated), then the method might work.

Hello everyone.
Is it possible to effectively use Dick O'Kane method in an attack on the convoy from a long distance (2km or more)?

Yes, but the further out the target is, and the shorter his length, the better you need to know his exact speed.

Take his length, and divide it by the range, i.e. 95 yards at 3000 yards is 31.7 yards per 1000 yards. 1 degree is 17.5 yards wide at a 1000 yards distance (same values apply if you use meters instead of yards), so the ship is 31.7 divided by 17.5 = 1.8 degrees wide. If the TDC aim is off by halve that angle (=0.9 degrees) then you risk missing the target if you aimed at it dead center.

So how do you know how accurate the speed must be? First you need to know how to convert speed to the lead angle.

The lead angle is based on the target speed, the speed of the torpedo, and the AOB of the target.

The formula is:

lead_angle= arcsin( Target_speed x sin(AOB) / Torpedo_speed )

(sometimes the arcsin button on a calculator is shown as "sin with superscript -1" or "inv sin" or "asin", or if you want to avoid that and allow yourself some inaccuracy simply multiply with 57.3 to get degrees. But this only works because lead angles are generally speaking quite small. You can't avoid the proper arcsin button on your calculator if the angle is more than 20 degrees)

Let's say for example, it has 90 degree AOB ( sin(90)=1 ), 10 knots speed and the torpedo moves with 31 knot:

lead_angle = arcsin( 10 X 1 / 31 ) = 18.8 degrees

(or 57.3 x 10 x1 /31= 18.5 degrees, ... and notice this simplification already cost you 0.3 degrees in accuracy)

The lead angle is roughly proportional to target speed. That means if target speed is actually 5% faster than 10 knots (so 10.5 knots), then the required lead angle is also about 5% more. (with our example: 19.8 degrees is required for 10.5 knots) Do you see the difference? 1 degree. If you thought it was doing 10 knots but in actuality it moved 10.5 knots, then the torpedo would pass behind the target. Because the stern is 0.9 degrees behind the center at that range. If it is further out, then the 0.9 degrees size would turn into a smaller value. And if the AOB is not 90 degrees, it's appearant size is even smaller. (times sin(AOB) )

You can easily get the speed wrong by 0.5 knots if you rely on the 3-minute plotting rule and use the 'crude' maptools (at those short track-lenghts). To get an accurate speed you need to average the distance over multiple 3-minute intervals.

As you might have noticed, a fast torpedo also help to reduce the lead angle, and limit the aiming error based on speed.

:har: That was good!!

Yeah, I had a bit of a snafu with the 'mini chron' mod. The first time I loaded it I had to reinstall the game. The second time (because I forgot which mod had the problem) I got lucky and only had to take it out of the mods folder. I would love to have a smaller Chrono but I'm not going to chance the mod unless there's a certified fix.
This has been a very good read so far, I'm learning a lot.
Cheers and Happy Hunting:salute:
D40

Just a quick question, you refer to Richard O'kane? or Dick O'kane? cuz as far as I've learnt Rich is the USS Tang skipper, while Dick is a member on Subsim famous for the sonar tutorial and other work here. Maybe he's set salvo to Left side of the periscope? thats the most possible explanation, or maybe the camera was on the other side of the ship, that could be apparent visual error. Of course I maybe wrong..

Dick is a nickname for Richard, so they are the same man. Although the man is deceased and not aware of Subsim ever.

When aaroblood, gutted and myself cobbled together the procedure we were inspired by Morton and O'Kane's mastery of the TDC and their inventive use of it in their attack strategies. But they left no precise set of instructions because they hadn't thought there would be a bunch of crazy people (us) using a fancy computer simulator to model World War II submarines.

After aaronblood and gutted drummed the principles of a U-Boat attack into my feeble brain, it was my job to adapt that to the unique qualities of the Silent Hunter 4 American TDC, which I did. We had discussions about what name to use and finally decided to name it after a famous US sub skipper of the war. Since Dick O'Kane's genius was the inspiration and historical justification for using a constant bearing technique with an American submarine, we named the method after him. We have never claimed that this is an imitation of any attack that Dick O'Kane ever made. It is only named in honor of him.

Pisces:

Could you describe will look like an attack on a ship from a distance of 3000 m, which moves at a speed of 10 knots and I'm set for the course at 90 degrees? Of course using the dick O'Kane method.Please. I'll be very grateful:yeah:. Sorry for my english