OLC Supermod + GWX + night surface attack

[Steeltrap]

Hi all

Running latest GWX + OLC mod (not the GUI part, however).

Reading the player guide, I noticed something in the comment on conducting night surface attacks (I like the reduced lighting - more realistic).

There is a comment to the effect that your best means of escape after firing was to dive deep and creep away. I have a few questions about that:

Surely that's indicative of the fact that all is not right? One reason for the crushing effectiveness of u-boat attacks early in the war was the fact that they remained surfaced when leaving, thus maintaining mobility and defeating the only technologically based means the Allies had of detecting them i.e. ASDIC. So an accurate sim would have you firing then fleeing on the surface.

As I've said before, I used NYGM before trying GWX. I had no perception that either was 'better', merely different (and I've not changed that view). When it came to surface attacks, however, NYGM did allow you to approach on the surface, lie stationary in wait around 1km off your targets' tracks, fire, then flee on the surface. Yes, there was a risk from starshells and searchlights. Putting your rudder hard over after firing so as to turn your stern towards likely threats before torps hit, however, then running like hell was usually effective.

At the risk of getting killed for asking it, does anyone know why it is that OLC + GWX should say diving is the better option when history, plus my experiences in NYGM, suggest otherwise? Let me stress I am not trying to start a 'this is better than that' flame war - I am simply trying to understand the difference.

It's also entirely possible I have misunderstood the operation of night sensors in OLC. My impression is that:
- aspect makes a large difference (as it should)
- warships are more likely to spot you than merchants (as they should)
- crew experience of opponents affects their ability to spot you (as it should)
- heavy weather makes you harder to spot (as it should)
- moving at higher speed makes you easier to spot (as it should, but only up to a point/depending on weather)
- I'm not sure what effect the moon state has: is it cosmetic in providing more light, or does that in fact make a difference (as it should)?
With all of this, it's the 'dive after firing' part I am trying to understand, as that seems contrary to my reading on the historical realities of the situation.

Any guidance/comments most welcome. Again, at the risk of belabouring the point, I am asking to gain greater understanding, NOT to suggest this is poor/crap whatever (the achievements of the modders frequently leave me amazed!).

Cheers all!

[nirwana]

Playing GWX and NYGM on a day by day base i noticed that in GWX somehow the escorts seems to pick up the noise of my diesel engines easier in comparable situations. Still be able to stay undetected at 12kts in NYGM escorts in GWX start heading into my direction if i run faster then 7knts. :-?

:hmm: Sometimes i get the impression that escorts in GWX investigate any non-warship sigs which are moving faster then the average speed of the convoy.

[onelifecrisis]

I didn't say it was impossible to escape on the surface, but for me (a DiD player) it's not worth the risk of being caught out by a searchlight. Early war, ASDIC is so bad that escape is a doddle under the waves in GWX. Surface escapes are possible - maybe even probable if you know what you're doing - but if you do get unlucky and you're caught on the surface by a spotlight then you're in very big trouble. That's why I recommended the submerged escape route.

Why don't you try a surface escape and see whether the game models it in a way you like? I doubt any amount of discussion will really answer your question as well as a test. :up:

[onelifecrisis]

Ooops, there's more...

It's also entirely possible I have misunderstood the operation of night sensors in OLC. My impression is that:
- aspect makes a large difference (as it should)
- warships are more likely to spot you than merchants (as they should)
- crew experience of opponents affects their ability to spot you (as it should)
- heavy weather makes you harder to spot (as it should)
- moving at higher speed makes you easier to spot (as it should, but only up to a point/depending on weather)
- I'm not sure what effect the moon state has: is it cosmetic in providing more light, or does that in fact make a difference (as it should)?
With all of this, it's the 'dive after firing' part I am trying to understand, as that seems contrary to my reading on the historical realities of the situation.

Yes you've understood correctly, but you seem to have underestimated the effectiveness of searchlights in GWX+OLCU. Or maybe not! I say again: try it and see. And please let me know how you get on! If your surface escape methods work well, I'd love to amend the OLC Players Guide to include your technique. :)

P.S. There is no moonlight in OLCU. If the moon is out, it just sits there looking pretty. However, night visibility is better on a clear night than it is on a cloudy night (with partial cloud visibility falling somewhere between the two).

[Letum]

It shouldn't make a difference, but using electric torps stops the destroyers going
straight at the place you launched the torps from.

[Steeltrap]

I didn't say it was impossible to escape on the surface, but for me (a DiD player) it's not worth the risk of being caught out by a searchlight. Early war, ASDIC is so bad that escape is a doddle under the waves in GWX. Surface escapes are possible - maybe even probable if you know what you're doing - but if you do get unlucky and you're caught on the surface by a spotlight then you're in very big trouble. That's why I recommended the submerged escape route.

Why don't you try a surface escape and see whether the game models it in a way you like? I doubt any amount of discussion will really answer your question as well as a test. :up:

Yes, a trial is what I will have once given the chance. I'm only on my 2nd patrol with the new setup and am yet to encounter a convoy - too early in the war, I imagine.

Once I've tried it as I would in NYGM, I'll report the results (I'm hoping the only lifeboats will be theirs......).

Thanks for the reply.

Cheers

[onelifecrisis]

(I'm hoping the only lifeboats will be theirs......).

:D Good luck! I'm looking forward to hearing about it...

[wdq4587]

I 've heared from someone (I guess a expert) that diesel engine sound in surface is not easy being heared by other surface ship hydrophone. For the wave disturb the sound transfer. But I still don't know the diesel engine sound of u-boat can be heared by a watcher or not in 1km distance.

BTW, I guess if you attack in long distance, for example more than 2km and shot 4 torpedos quickly. You may got enough time to escape in surface. If you shoot in short distance, you do not have enough time to run away in surface. And in NYGM I always been located by DD search pattern by ping when I escape submerged slowly.

[onelifecrisis]

Playing GWX and NYGM on a day by day base i noticed that in GWX somehow the escorts seems to pick up the noise of my diesel engines easier in comparable situations. Still be able to stay undetected at 12kts in NYGM escorts in GWX start heading into my direction if i run faster then 7knts. :-?

:hmm: Sometimes i get the impression that escorts in GWX investigate any non-warship sigs which are moving faster then the average speed of the convoy.

I 've heared from someone (I guess a expert) that diesel engine sound in surface is not easy being heared by other surface ship hydrophone. For the wave disturb the sound transfer. But I still don't know the diesel engine sound of u-boat can be heared by a watcher or not in 1km distance.

Enemy hydrophones cannot detect you when you're surfaced in GWX.
Nor can the enemy watch crew's "hear" you.
However more speed does make you more visible to enemy visual sensors when you're on the surface. This is because more speed means more bow spray and more wake, and the spray can be spotted by the watch crews, and the wake can be spotted by aircraft.

[Steeltrap]

I have always concluded that the single biggest reason for the failure of the u-boat campaign was the continued advances in Allied radar.

Why? Because that forced u-boats below the surface. Once there, they lost their ability to manoeuver in any meaningful sense. This brought a number of factors into play:

- endurance: you will eventually run out of air/battery power.
- ASDIC: the ability to remain undetected while submerged was reduced with each improvement in ASDIC. Ultimately, they knew your bearing, distance and depth.
- ASW weapons: hedgehog, squid etc. means they don't even need to get to you. With the improved positional fixes from improved ASDIC, you're toast. Add the Mk24 mine (really a homing torpedo, introduced after the technical glitches were sorted) and it's not even fair.

So, the corollary of this is that success is achieved through remaining on the surface so long as is feasible. That was the experience of the most successful commanders. Once you dive, you give the initiative to the enemy and surrender many of your options - never a good strategy!!

I shall see how far I can carry that idea......

[Steeltrap]

However more speed does make you more visible to enemy visual sensors when you're on the surface. This is because more speed means more bow spray and more wake, and the spray can be spotted by the watch crews, and the wake can be spotted by aircraft.

That should be heavily influenced by the sea-state: spotting any ship at sea from the air in heavey weather is very difficult, let alone one as small and close to the surface as a u-boat. The wake is largely visible due to its contrast with the surrounds: the human eye is most sensitive to movement and 'difference'. When the sea is calm, a wake is like a line on a blank piece of paper. When the sea is whipped up, especially if whitecaps and rain, that same line is drawn across a piece of paper covered in lines/scribbling: you might see it, but it is immensely more difficult to do so. Also, it's hard to appreciate just how small something like a u-boat is when viewed at sea from any sort of altitude (bear in mind the Brits confused the Sheffield with the Bismarck - something you'd not do from sea level!!).

Cheers

[wdq4587]

- ASDIC: the ability to remain undetected while submerged was reduced with each improvement in ASDIC. Ultimately, they knew your bearing, distance and depth.


From my very little Destroyer Commander experience. It seems ASDIC sensor can not know your depth. Although a experienced commander can estimate your depth by continuous ping and check the distance change while approaching you. And the blind area in front also has relation with target depth.

[tomfon]

It seems ASDIC sensor can not know your depth.

I doubt that.
Anyway, if it can estimate the distance
then the depth can be calculated.

[onelifecrisis]

[spray/wake visibility] should be heavily influenced by the sea-state...

This is where my knowledge gets hazy. The complexity of visual sensors in SH3 ultimately defeated me and I abandoned my "quest" to understand them completely. I know that weather is one variable which has an effect, but whether or not it negates the speed variable I can't say for sure.

I'm reasonably certain, though, that neither GWX nor NYGM could alter whether or not it does. Modders can change how pronounced the effect of each variable is, but AFAIK the releationships between the variables are hardcoded.

[onelifecrisis]

It seems ASDIC sensor can not know your depth.

I doubt that...

Me too.

[wdq4587]

It seems ASDIC sensor can not know your depth.

I doubt that.


In Destroyer Commander the DD's sonar only can rotate in horizontal just like u-boat hydrophone. I guess that's the real behavior. If DD using a narrow angle hydrophone to recieve ping echo. The operator may miss the submarine echo while scan. A good solution is using a wide angle hydrophone to scan and a narrow angle hydrophone to locate target. But I guess the designer think it's unnecessarily complicated. The best solution is using phase array, but you can not hope that in WW2.

[baggygreen]

Trigonometry and probability lads :D

god i hated that stuff at school... forgotten most of it too:know:

[Steeltrap]

My comments on the subject of ASDIC and knowing your depth was based on historical reality, not how the sim handles it. As a matter of reference:

"The 147 type was a depth finding set that complemented the main Asdic set (144Q and 145Q) and the Q attachment. Its most notable feature was its sword shaped oscillator operating at a frequency of 50 Kcs. Physically, the sword was four to five inches wide and approximately four to five feet long. To prevent interference with the main set, the 147 was mounted ahead of it. When not in use, the sword was stored in a lifting tube mounted within the hull. When deployed, the sword could project a fan shaped beam being narrow in the vertical plane and wide in the horizontal plane. It could be trained up to 65 degrees horizontally and 45 degrees vertically.This new design, which added depth determining capability, could accurately track a target within 20 feet. Another feature was its integration with Squid, an ahead-throwing Anti-Submarine (A/S) mortar. Together, they formed the most effective A/S weapons system of World War II. When an echo was received on a 147B set, the operator would tilt the sword until the echo was lost. He would then reverse the procedure until the echo was heard again, then continue sweeping until the echo was lost on the opposite end of the sweep. Every echo received would then be printed on the depth recorder. A line of light on the depth recorder would indicate the centre of the echo trace. The operator would then look at a calibrated scale and read off the depth directly in feet. From here, the information was used for setting the pistols on depth charge fuses or transmitted to the Squid mount. When Hedgehog was fitted, depth information was not applied, since this weapon had to strike a solid object before it exploded.

New style recorders automatically gave range and direction for steering, while the set itself could automatically set and fire Squid mortars. After the war, it was calculated that a well trained 147 team could achieve a 50 per cent kill rate, nearly nine times that of depth charge system and substantially more than Hedgehog. The 147 set was first tested in March of 1943 and entered service with the Royal Navy in September of that year."

[My italics/bolding]

So, prior to the introduction of the 147 set as a complement to the main ASDIC, escorts did not know depth of target - they could only estimate it based on their knowledge of the set's operation and the range at which they lost contact when approaching a target (the greater the distance at which you lose the target, the deeper it is).

In practical terms, from Sept '43 onwards there would be escorts equipped with ASDIC that would know your range, bearing AND depth - what's more, the system would provide info for configuring DCs to the right depth (and trigger their dropping) AND/OR traing hedgehogs/squids (with depth setting for squids done automatically) and fire them. In short, it becomes an automated system for killing your boat.....

[wdq4587]

Thanks for the information! My guess was wrong. The designer don't think it's unnecessary. The war really push the technology very much.

And I had to say. If the game designer make this, we do not have survive possibility on such attack.

[Pisces]

...This new design, which added depth determining capability, could accurately track a target within 20 feet....20 feet? That's 6 meters, that can't be right.

[Steeltrap]

...This new design, which added depth determining capability, could accurately track a target within 20 feet....20 feet? That's 6 meters, that can't be right.

Well I imagine they mean 20ft of the target's location. Even if the target is around 70-75m long, such as a u-boat, it means they'd be able to track it within 20ft of either end or above/below. The point is that the escort will 'know' where you are to a degree that hitting you with an effective attack is much more likely - as the real life performance of ASW performance showed from late '43 onwards.

[tomfon]

In practical terms, from Sept '43 onwards there would be escorts equipped with ASDIC that would know your range, bearing AND depth - what's more, the system would provide info for configuring DCs to the right depth (and trigger their dropping) AND/OR traing hedgehogs/squids (with depth setting for squids done automatically) and fire them. In short, it becomes an automated system for killing your boat.....

And i think GWX features everything you mention except from the squids.
So, good luck to everyone who fights the war after September 1943.:lol:

[Steeltrap]

OK, I had a chance to do a night surface attack.

Weather was wind @ 9m/s, overcast with 'reduced' visibility (i.e. around 5km max).

Convoy was doing 5kts on 115deg (I'd done a submerged attack earlier, and I think the convoy had slowed from its previous 7kts due to a damaged ship).

So.....

I approached convoy from port quarter (there was no port escort - not complaining...). I plotted the course of the single remaining vessel on the outer port column (I'd sunk the other 2). I then positioned myself to be lying 1.2km from the target's projected track, with my stern aimed along a bearing of 225 deg (i.e. giving an AoB of port 80). Remained stationary. So, what happened?

I fired when the solution showed a 5 degree gyro angle, approx distance to impact of 1.2-1.3km. I then started moving away at 1/3 speed.

Torpedo struck where I had aimed (slightly forward of bridge - this ship had been struck slightly aft of bridge, but had refused to sink). It started to sink almost immediately.

Meanwhile, other ships started using searchlights to port, and the fore and aft escorts (both frigates) started heading to port side and firing some starshells. I advanced to standard speed. I had my stern facing the convoy, so my aspect to the escorts meant I was showing very little in the way of profile.

The closest an escort got to me was 3.4km, and they didn't spot me.

So - target hit and sunk as intended and I escaped on the surface.

Some observations:

1. Weather and visibility favoured me heavily. Max visibility of 5km and night meant the likelihood of a merhchant seeing me would, I assume, have been all but nil.

2. There was only one ship left on the port column. This meant there weren't other merchants nearby to use searchlights effectively.

3. The nearest escorts were fore and aft of the convoy, both around 4.5km from me when I fired. With a narrow aspect to them, it was all buyt impossible for them to have seen me before I fired. I was heading away from them before the torp struck.

It would be interesting to see what might happen when I try a bow shot with more than one ship in the column, thus needing to turn 180 deg (and present a broadside to them) after firing. I will experiment further.

================================================== =======================================

For some reason, SHIII has stopped working!!

I get to the GW loading screen and then it stops with an error message (something to do with sh3.exe and simdata.dll). I use SHIII commander, but I've tried loading directly without that and it still fails. I've changed nothing about the install - I saved after my attack, but only when well away from the convoy (more than 50km I think).

Any thoughts??

[onelifecrisis]

Thanks for the info! Yes, it sounds like conditions were heavily favourable - just about perfect, in fact. I'll be waiting to hear how you get on in other conditions!

(about the error... sorry, I've never seen an error like that... hopefully someone has :-?)

[Steeltrap]

Thanks for the info! Yes, it sounds like conditions were heavily favourable - just about perfect, in fact. I'll be waiting to hear how you get on in other conditions!

(about the error... sorry, I've never seen an error like that... hopefully someone has :-?)

I detected the convoy via hydrophone. When weather is like that I usually dive to 30-40m and proceed at dead slow speed (about 1.5kts). That way I can detect things in an area far greater than I would on the surface, plue it eliminates the possiblity of the 'destroyers in the mist' scenario!

Being stationary and able to move away from the convoy without ever getting broadside-to meant the whole situation was, as you've remarked, pretty much perfect.

[wdq4587]

When weather is like that I usually dive to 30-40m

I think in theory you should dive to that depth and may be even to 60m. But in SH3 I guess there are no difference deep than periscope depth.

Also want hear more test from you. I always attack too close for test that.

[nirwana]

It would be interesting to see what might happen when I try a bow shot with more than one ship in the column, thus needing to turn 180 deg (and present a broadside to them) after firing. I will experiment further.
Any thoughts??
I tried this once in a while in night attacks and with comparable conditions at daytime. I stayed only undetected in the day attacks as long as i made my u-turn with no more then 4 knts. It always looked like it would take forever but it seems to work pretty well as long as i have finished the u-turn before a target takes a hit.