Problems and disadvantages with electric torpedoes (the early ones)
 

Earlier today I had my first engagement of my current patrol.It was a lone merchant heading east from US towards Britain.I was in the AL sector,about midway,and it was very dark.As electric torpedoes were the first in the tubes I had no option but to use them.I decided a close range submerged shot of about 500m would be my attack,and so I proceeded on my intercept run,as I was already ahead of him.One hour later he appears as scheduled and I prepared my torps.Speed was set to 7,range 5-600m,depth 3,impact pistol.I waited until he was at a bearing of just over 10deg in the PS and let fire.I don't really like to do this,but I watched its progress on the torpedo plan screen and lowered my scope.I watched in horror as the torpedo passed behind him,yet only slightly.
I was very disappointed with the torpedo's performance,and this was the first time I have really used these tortoise sticks,apparently for good reason.I much prefer the speed of the steam torps.
I immediately swung the boat round and headed north until on the edge of visibility,ready for another attack,only this time with the deck gun :damn: , i'll pop up in front of him and give him a warm welcome.
Can someone work out what went wrong with this shot?.My initial judgement was the poor speed,and maybe I waited too late to fire?,maybe it should have been released at about 20deg?Do we need to fire sooner to compensate for the slow speed? :nope:
If someone can provide me some info on optimal firing angles on when to release torps at certain ranges,especially the tortoise sticks,that would be great.

(I cant wait until the ETorps become faster like the steam ones)

Cheers guys

Did you forget to open the torpedo doors (Q) as this can delay your shot causing you to miss

Anything could have caused that shot to go wrong... anything except the electric eel! Electric torps are excellent, consistent performers in SH3. They don't get spotted by the enemy (the gas torps do) and the extended TTI is actually very useful as it allows more time to fire additional eels or to start your evasive manouvers before the first eel hits its target. Also, there's a stock bug on multi-speed torpedos which sometimes prevents the selected torpedo speed from being used in the TDC calculations (resulting in a miss) but that bug doesn't affect electric eels because they only have one speed setting.

The problem was definitely with your solution and not the torpedo, as the TDC calculates based on the speed setting of the torpedo.

Indeed electic torpedoes are much more realiable.The only advantage is the steam torps is near 50% greater speed and range over the electric aals.

The tube doors were open,I do this on my final leg into position before the target arrives.
Speed was confirmed previously as 7kts,and so I am expecting the TDC setting to also be correct.
I am convinced it must have been the firing angle of only 10deg.I think I should have released the torp earlier.I have fired perfect steam torps at 10deg bang on,yet this one passed just by his stern.
Do you agree the firing angle may be to blame?This of course is 10deg from perpendicular facing of the target.
Real gutted about that waste :nope:

Could you explain exactly how you confirmed the speed? Over how long? And what was the difference between periscope bearing and gyro angle at the time of fire, this 10 degrees? If you can remember. 7 knots target and 10 degrees lead suggest the TDC calculated the aim for a fast type-1 (7 knots target@ 90 AOB vs. 44knots torpedo= 9.1 degrees lead). A slow electric (30knots) would need 13.5 degrees of lead. Any chance you had selected a tube with a fast type-1 in it previously? Or else the speed of the target would have been around 5 knots (30*sin(10)=5.2). That is quite a difference, but possibly enough measurement fault if you used only the 3m15s rule.

The torpedo speed the TDC was useing was wrong. When you have mixed T1/T2 torpedoes loaded in the tubes the TDC never auto-sets the T2s to the correct speed when switching between them.

The work-around is when you go to the tube loaded with the T2 click on the torpedo's speed switch. That'll set the TDC to use the correct speed for the T2 torpedo.

Also, get in the habbit of useing all steam, or all electric, loadouts. Up until 1943 I like useing T2s in spring/summer and T1s in fall/winter. After 43 I stick with T1s and just do long range spreads into convoys with the low speed setting.

I used the 3m15s rule over a period of about 30mins,as I was level with him at 90deg and monitored his position in my scope for said period,he was steady at 7kts.The fire angle from perpendicular was 10 deg in the scope to target as I said.
Your 13deg sounds about right as it would give the electric more lead to hit the target.I was pretty sure just after firing that my firing angle was too late.Future firing angles of 15-20deg should still give me a good contact on his broadside.I just need to get used to the slower speeds.
I was previously unaware of the TDC using settings for fast steam torps instead of the slower electrics,that is pretty bad I think.How do we get around that problem then? :down::nope:

Thanks.

My mixed torpedoes was,4 electrics in the fore,and 4 steam in reserve.I didnt have say,2 steam and 2 electric.I originally came up with that loadout to give me more flexibility during both day and night attacks on convoys.May be a bad idea.Probably better to just stick with a full load of what you feel comfy with.
Also,I always manually set the speed settings for the torpedoes,individually if that is to be the case,yet up to this point I have never used shots using torps of differing speeds.

I'ts abit of a bug with SH3. What was happening is the TDC was useing 30 knots (T1 low speed setting) as the torpedo's speed for the T2 rather than 28 knots. Even with the crew doing the torpedo solution it'll pass just aft of target, or at best hit the stern around the ship's rudder.

Just clicking on the speed switch for the T2 torpedo to be launched will get the TDC correctly set for 28 knots. I always do this, and confirm 28 knot setting with the TDC, when useing T2 torpedos out of habbit now.

akula

Thanks a lot for that bit of info,this perfectly explains what happened,as i'm quite certain my actual attack setup was sound

Cheers :yep:

Two things.

1) I was unaware that type IIs had a speed of 28 knots.
Wikipedia says 30 knots. uboat.net says either 28 knots or 30 knots depending on whether torpedo was preheated. All other sources I checked say 30 knots. I have never had a problem using the 30 knot speed asssumption for TIIs. Perhaps AKULA_71 is misremembering a problem with Falkes, or with resetting the speed after a G7a has been fired from the tube, or the problem applies in GWX but not stock, which is what I think Mr. Riley is using.

2) Firing at just more than 10 degrees should miss aft with a G7e at 500m on a small ship. The correct angle is 13 degrees. If you were not actually perpendicular to the target's course, or you had the AOB set wrong, the error could be compounded. Since G7e torpedos are slower, they are more likely to miss as a result of faulty solutions than a G7a on fast speed (the angular differences are greater.)

Roald,

You explained the problem just about as easy as is possible.It is that shift from 10deg release of the torpedo to 13deg that I find important.Naturally,I was too late in firing,this is what I have been trying to explain.I now need to find out when to release the torpedo at different ranges using electrics.I think the further out you are with electrics it gets a lot harder to hit something,whereas with steam it isnt as drastic.

Roald, just one thing before I go
Staying with the 7kt ship I was engaging
We now know the correct fire bearing was 13deg
What would it be for
1000m
1500m
and so on,upto about maximum visibility range?
THATS what I want to know.

Cheers.

Oh,I forgot,my last UBoat was sunk on the night of 2nd Nov 1942,as you predicted,yet not from planes.

When you are perpendicular to the target's course, the correct target bearing doesn't change with range to target. It will be 13 deg for any range. At target bearing 13 degrees, target speed 7 and torpedo speed 30, the gyro angle is 0 no matter what the range is.

A change to range to target doesn't affect gyro angle if gyro angle is 0.

Yeah, when it became obvious that the planes were not going to get you I had to send out a hunter killer group, along with some bait.:haha:

Correct.


It's more difficult to hit targets far away only because their length becomes a smaller angle the further away they are. If you measured the speed wrong, a ridiculous AOB or set a completely wrong range correction incase gyro angle was not 0 or 180 degrees, this determines how wrong the lead is. Your (Paul Riley) plots over 30min or so would seem to be reliable, assuming it is an average over the first and last plots. Comparing the distance between adjacent plots by moving a cirlce doesn't help. That's just as accurate as between just two plots. Assuming 7 knots is correct, the lead would be either 9.2 or 13.5 degrees for the different torpedo speeds (resp. 44 and 30), a difference of about 4.3 degrees. This 4.3 degrees is 75 meters wide per kilometer of distance. At your range the torpedos were about 45 meters behind what you intended to fire at. Midship, or aimed at prop/rudder? Because a most common shiplength is 78.5 meters. All theoretically speaking ofcourse! Does that conform to what you experienced?

It makes perfect sense Pisces,yes,thanks.
Thanks to both of you for your help here,and I am taking careful notes as we speak.Everything is becoming ever more clearer now,the more I actually understand how the torpedo operates,or more accurately how the TDC prepares the torpedo for firing.
Thats all for now.
I will let you know what happens in any upcoming engagements I may have over the next day or so...or so I hope.

I forgot,the shot that missed passed by a cat's whisker of the ship's screws,at least it was that close on the torpedo solution screen.The miss was VERY close.

:up:

Hmm. You learn something new every day!

I never use the electrics in the first 12 months of the war. The early ones have serious reliability issues. I've watched the thing's bounce off targets without detonating on perfect 90 degree AOB shots, or suddenly dive UNDER ships at the last moment, (I did a patrol with event camera on to find out why I kept missing, and found I wasn't, it was just the torpedoes failing) anything but actually work. By December 1940 though T2s seem to be mostly reliable. I still prefer the T1 steamers though, they still seem to have a lot fewer duds than the electrics. I only use electrics in the day time with calm weather when a steamer would be too visable.

Yes early Electric aal do have problem with being dud.I myself have seen 90degrees hit bouncing off and if there is anything more annoying that near misses it is failure to detonate on hit :damn: