Sub Skipper's Bag of Tricks

[19Herr_Rapp86]

Kapitanleutnant Rapp

[19Herr_Rapp86]

Off topic I know. Sorry guys

[Rockin Robbins]

He really should quit smoking. That could kill him, you know!

[19Herr_Rapp86]

Smoking was the cause of a majority of the u-boat crews deaths in WWII!!!! LMAO

[Platapus]

Originally Posted by Rockin Robbins

And as a bonus, I found something else. You can put your target abeam and eyeball a relatively parallel course, right? You don't have to be accurate: 25 degrees off one way or another still yields pretty good results. Some idea of range is necessary too. But for what it's worth:


OK, that means that you're on a parallel course with your target. Your courses are the same, but of course, your speeds are different. We'll just say he's a mile, 2000 yards, away. Taking a series of bearings, his bearing is decreasing, he's falling back of 2 degrees per minute and you're going 10 knots. So he's traveling two knots slower than you are! Peg that guy at 8 knots.

I could not tell from your post whether these were your words or someone else's words you were quoting.

I do not believe that would work. It is really designed for a stationary observation viewpoint where it is simple trig function to calculate the angle. Hence the warning about the statement disregarding the movement of the submarine.

This is because, if stationary, you are constructing a simple triangle with the submarine at one of the vertexes and the ship movement forming the two end points of the opposite side of the triangle. Knowing the relationship between the angle changing over the period of observation and the range, it is possible to calculate the speed. However at ranges over 2,000 yards one would either need to be able to measure the bearing to 0.01 precision or extend the period of observation for longer (10-15 minutes minimum). This can be demonstrated using Excel with the formula =DEGREES(atan(b/a)) where b= the target ship and a= range.

All this works great at long as the submarine is stationary. Once the submarine moves the simple triangle problem becomes a very complex quadrilateral problem.

I just don't think we would ever have enough information to be able to solve a single quadrilateral problem like this. I am trying to work out whether a series of contiguous quadrilaterals might be workable but so far it does not look good.

If, and this is a large if, I can steer my submarine on a parallel course with the target ship, the problem becomes a trapezoidal problem. But the only immediate payoff of that would be that I could calculate the target's AoB and, therefor, the target's course.

AoB = 180 - bearing to target (expressed as a number 0-180 not 0-359). Note, this only applies when the submarine is on a parallel course with the target.

If, I somehow know the target's speed, I can take two bearings over a measured interval and calculate the range...this is not a simple formula but a combination of separate geometry and trig calculations. I am trying to find them and baring that I will try to create it.

Surprisingly calculating the range using this method is pretty straightforward if you use plotting paper and scale drawings, but trying to find a series of equations is challenging.

[Rockin Robbins]

Actually the post tells where the method comes from and the info is a screenshot. It's part of the official US Navy Submarine Torpedo Fire Control Manual of 1946. And it is self-validating. Just reading it and understanding what it says reveals a proof of concept from within the method.

It's a simple concept of relative motion. You are constantly in motion. In fact, if you are at the equator, you are rotating with the earth at 1,000 mph, while simultaneously orbiting the Sun at about 100,000 mph. However, in our relative motion calculations with the submarine and target, we ignore both of those components and do not end up with a multiple variable solution.

This method simply stops the motion of your submarine and calculates the target speed relative to your stopped submarine. Let's say you calculate 2 knots, Yeah! But the sub is moving 10 knots. Fine. We know he's going 2 knots more than we are. 10 + 2 means our target is moving 12 knots.

If our method "stops" our submarine, we eliminate that variable. The result is that our resulting single variable solution is only calculating the target speed relative to ours. It's the simple method of eliminating a variable by expressing it in terms of another variable, then ending up with a single variable equation.

It works. Don't believe me, it's not my idea. Believe the US Navy!

[Solidsnake2234]

I need the Sonar manual targeting, yet all the downloads were erased from the website it's on. can anyone help me?

[Rockin Robbins]

I'm still looking for a sticky place to put all the video downloads. The written tutorials and mods are okay, but the videos were all dumped by Filefront when they became Gamefront. They're busily destroying their usefulness and that is somehow supposed to make them money. It's very complicated I'm sure and it resulted in this community losing a lot of valuable information.

I had planned for that to happen from the beginning and have all my material backed up locally. But, as I said, I'm still looking for a good and sticky place to put it all back on the web.

Any ideas?

EDIT: I am uploading the WernerSobe videos to 2shared right now. We'll see how long they live. When the files are uploaded I will update links. Sure wish these tutorials could live on Subsim where they would be valued and preserved.

[White Owl]

I'll toss out the kinda obvious suggestion for the tutorial videos: how about Youtube?

[Rockin Robbins]

Stooooooooooooopid me. Duh. That's a brilliant solution and I'll get right on it.

In the meantime the WernerSobe video links are now fixed in post #1 and point to 2shared for now. That will change as I get videos to You Tube.

Thanks for the necessary step of pointing me to the obvious! Yikes. Just when I had it all together I forgot where I put it! Somebody slug me.........

[White Owl]

It only seemed obvious to me because it seems I spend half my internet time these days uploading things to Youtube.

[19Herr_Rapp86]

I seem to have found a reliable solution for destroyers. (Though not recommended. My tactics seem to be more aggressive than a lot of the sub skippers I see on here. Besides, the speed and maneuverability of a destroyer make for a poor target and tend to waste fish.) So far, have successfully sank 14 destroyers using this method, and would be good to note that I have only encountered 14 destroyers on my patrols I set my course to have a 0 degree bearing on my target. When he commences his attack run (points his bow straight at you, pings with active sonar, and starts zig-zagging), I completely clear the TDC, set first to fire at a 0 degree bearing, next 2 (in rapid succession), at 5 degree left and right bearings, and the next 2 at 8 degree right and left bearings. The destroyer can not as it seems, outmaneuver that particular spread of fish. It seems thus far as a good destroyer tactic. (Though please keep in mind that it requires 5 torpedoes, not counting the possibility of duds, run-deeps, etc, and that I personally recommend not attacking a destroyer unless the situation is absolutely perfect for you and you have not been detected. This method I will note is for use when you have been detected and the destroyer is making his attack run) (also to note, the best range for this particular spread is between (1200 and 900 yards)

[Rockin Robbins]

That would work. But expending five torpedoes for 1300 tons is mighty expensive tonnage. That's one I would only use if my life depended on it. Usually I put 'em on my stern and do the same zero degree solution in the TDC. I preset the TDC into send bearing/range mode.

I hit ahead emergency as the DD comes up on me, lock the target and hit the send bearing/range button. Then it's attack map time. As soon as he gets inside 450 yards, fire one and hit crash dive, keeping full throtte. make a turn when you're 100' down or so, straighten out the rudder when you're at least 45º off course, wait for "passing thermal layer" and hit the silent running button <ctrl-z>.

That way either I heard a boom and I got my DD or I missed and I'm safe. Either way I've only collected 1/4 of the guaranteed misses of the high probability shot and can try four more times if I have to. This is about a one-third chance of sinking the DD. The key is to continue in a straight line as you dive until after the torpedo hits or misses. Then make your avoidance turn. Too early and he will follow the turn resulting in a guaranteed miss.

[Rockin Robbins]

Videos are uploaded to You Tube and all links in post 1 are good to go!

[19Herr_Rapp86]

Hey bud, says your vids have been removed by youtube because they are too long