Am I still cheating?

[Freiwillige]

The periscope lock feature just simulates you tracking the target visually and did not actually exsist. If you wanted to do it manually you could start the speed watch wait roughly 30 to sixty seconds and then point your scope on the exact same spot on the target and hit the stop the watch again to calculate speed. As for the weapons officer position, I like to think that as I am looking down at the accurate plot my Number 1 officer is feeding me the information. Surely I cannot be two places at once!

[Pisces]

How german TDCs worked exactly I don't know. But I am positively sure they didn't have cameras that could do image processing to maintain a lock. The observer behind the optics would have needed to keep the line on the target in the periscope. So it doesn't seem realisitc AT ALL to me. Not to mention it forces you to limit your direction of firing. I'll explain in the end.

From what I've heard (here in subsim and other sites on WW2 submarines) the Germans didn't have a TDC that could keep track of a targets position automatically 'internally'. The crew would have needed to feed it current data for an update of it's aiming, of which bearings would be most important. The Americans did have a TDC that could update target positions (and provide aiming data for it) automatically based on it's mechanical 'memory'. Infact it had a function called "Position Keeper". You might want to do a search in the different forums here on TDC history for more info. Keep your eyes peeled for posts made by Hitman. He's pretty much our expert here on this kind of technology.

When it comes to the Silent Hunter 3, the TDC it's not very smart. It can only keep track of AOB based on changed bearings, like moving the periscope/UZO viewing direction. (once you change course the device is helpless in aiming.) But this actually makes it flexible if you want to target multiple ships, ...poor Sh4 players. The other dials are needed to make aiming corrections for an 'exact' hit.

If you lock the scope the torpedo will allways be aimed to go to the mid-ship of the locked target. But why should it? I like to aim at the front mast or somewhere near it's rear. Or rather, I like to set up the periscope direction in advance and wait for any location to pass through the aiming line. 'Midship' because I could be uncertain of my aim? Hell no!, with propper settings anyone can hit spot-on. I think the only reason you 'need' to lock is (a software technical reason) for the recognition manual to pass-on the target ID to the Notepad for range measurement. (Ok, also during the speed measurement, but it really shouldn't be forced upon the user.) When that is done there is no need to lock. Until you need to range another (un-IDed) target.

This Sh3 tdc gives a gyro angle (for torpedo to turn) input to all torpedos. But not all are fired. So only those that are fired, are sent in that direction (with or without spread). The key is not to lock the scope. Then aim the scope where-ever and the torpedo goes there. (well, actually to the future position of whatever is 'there'.) The only thing to consider is the right setting for the range dial of the TDC. This can be different some kilometers in convoys. Since speed and course is constant (we hope that anyway), only bearing and range defines where the torpedo actually steers to.

I hope that clears up some of your questions.

[mmm...Dönitz]

Thanks for the replies.

So… The periscope lock feature, while not historocally accurate just makes your life a bit easier when tracking a target - plus it seems like you don't actually need to use it. I'll try a few speed measurements with and without.

My main concern is now the validity of modifying my targetting solutions at the TDC (where someone is magically plotting the ships' locations in real time) to compensate for my currently inept estimates of range, AOB and speed.

[Pisces]

Originally Posted by mmm...Dönitz

My main concern is now the validity of modifying my targetting solutions at the TDC (where someone is magically plotting the ships' locations in real time) to compensate for my currently inept estimates of range, AOB and speed.

The stock manual targeting procedure is too dependand on a correct guess of AOB for good results. Range is usually accurate if the ID is good and you lined the level up with the waterline and propper end of the mast (instead of just where the pixels end, because of the limits inherrent of rendering them). Not much to guess there. But speed measured (even when locked) is completly dependend on the accuracy of the range and guessed AOB in the former steps. Only allowing speed in steps of 1 knot is not helping either. Speed and AOB are THE MOST important variables in leading the torpedo..

If you really want to pursue manual targeting further I would advise you to investigate/install the Ujagd tools or OLC Gui targeting mods. Or rely more on plotting on the map to get your data. Those mods and manual plotting is much more representative of the real german optics and procedures used. And every data needed for the procedure can be measured with them, not just estimated.

[Hitman]

From what I've heard (here in subsim and other sites on WW2 submarines) the Germans didn't have a TDC that could keep track of a targets position automatically 'internally'. The crew would have needed to feed it current data for an update of it's aiming, of which bearings would be most important.

Correct, the german TDC had no automatic position keeper, unlike their US and british counterparts, but it could update the solution following the movement of the optics. When the Kaleun or IWO asked the TDC operator to set it in "Lage folgend" (AOB following) mode, the TDC bearing dial was directly linked to the scope or UZO, and moving them updated the solution correspondly. When set to "Lage nicht folgend" (Not AOB following), a blue lamp lighted and the TDC accepted inputs in all its parameters, (Distance, AOB, Spread, target length...) plus it did no longer follow the optics. SH3 has therefore a very good representation of the german TDC except that our home computers calculate the solutions nearly instantly (See what I explain next) unlike what the real tool was able to do.

I like to set up the periscope direction in advance and wait for any location to pass through the aiming line

That's basically what was done in WW2 U-Boats, not just because of the convenience of being able to aim at different parts of the ship, but also because the TDC was an analogue mechanical calculator and it took some seconds for it to provide the proper solution (At that moment a lamp was lit to show the solution had been created) after a change in any of the inputs. Obviously simply moving the optics (bearing) allowed for faster update than if changing other inputs, but still it was considered better to shoot at a fixed, pre-chosen bearing with a fully calculated solution.

My main concern is now the validity of modifying my targetting solutions at the TDC (where someone is magically plotting the ships' locations in real time) to compensate for my currently inept estimates of range, AOB and speed.

The most relevant factor here is speed, AOB is important but not that much (And also depending on the relative position of target and attacker, f.e. a 80º AOB instead of a 90º one is not as important as a 20º to a 30º error). Distance to target will only matter if you do angled shots. The Gyro Angle indicator on your scope screen is not causally there: The closer you are to a zero GA when shooting the less will distance matter. See my post about convergence here to understand it better: http://www.subsim.com/radioroom/showthread.php?t=121744

Also, speed and AOB will be less relevant the shorter the distance to the target. German commanders went really close before shooting, always as close as possible (Less than 1000 metres) and as much perpendicular to the target as they could, and that minimized errors in calculating/estimating target data.

[mmm...Dönitz]

Originally Posted by Hitman

Also, speed and AOB will be less relevant the shorter the distance to the target. German commanders went really close before shooting, always as close as possible (Less than 1000 metres) and as much perpendicular to the target as they could, and that minimized errors in calculating/estimating target data.

I think I'm finding the same thing! I did quite a lot of torpedo practise last night and although I can get hits on larger targets from over 1km away, the smaller ones I'm still missing.

I'm also now using the protractor tool on the navigation map to measure AOB while trailing about 1km back, about 130deg AOB port or starboard. I'm getting a lot closer, but for this type of shooting I need to close the range a bit more. I'm also only using the attack plot to check my solutions, not to adjust them.

I went to bed furious that I’d missed a coastal merchant moving at only 2knots from the stern tube, 700m range, zero gyro angle. Turns out that I've been compentating for my shots tending to hit further aft of my aiming point, so I've been aiming slightly ahead, or right on the bow, to compensate. Unfortunately I failed to appreciate that on a simple shot with accurate TDC data this would make me miss

I'm still hooked

[Hitman]

Turns out that I've been compentating for my shots tending to hit further aft of my aiming point, so I've been aiming slightly ahead, or right on the bow, to compensate.

Aiming ahead (leading the target) is something that can end up being very intuitive with practice Otto Kretschmer reportedly sunk some ships with the not very scientific method of raising his fist and saying "When the target is hidden by my fist, we will shoot". Obviously he had a good seaman's eye for estimating velocity triangles mentally, but again it is something that practice makes better.